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PHILIPS SERVICE SOLUTIONS GROUP
PHILIPS TECHNICAL TRAINING
PTV900 SERIESPTV CHASSIS
TRAINING MANUAL
PHILIPS TECHNICAL TRAININGONE PHILIPS DRIVEPO BOX 14810KNOXVILLE, TN 37914-1810PHONE: 865-521-0318FAX: 865-521-4818EMAIL: [email protected]
P H I L I P S
TECHVIDEOTAPE SM A N U A L S TRA
ININ
G
TABLE OF CONTENTS
12 AND 8 VOLT REGULATORS 95.2 VOLT REGULATOR 10AUDIO SIGNAL FLOW 29BOARD LEVEL TROUBLESHOOTING 37CRT DRIVE CIRCUITS 17CONVERGENCE ALIGNMENT 52CUTOFF AND CATHODE CALIBRATION 21DIGITAL CONVERGENCE CIRCUIT 28DISASSEMBLY 50FULL POWER SUPPLY 8GREEN CRT PANEL 19HIGH VOLTAGE AND SHUTDOWN 26HORIZONTAL DRIVE CIRCUIT 23KEYBOARD 35LIGHT PATH PROBLEMS 3LIGHT PATH 2LINE CONDITIONER PANEL 5MICROPROCESSOR 32PIP CONTROL 13PIP POWER SUPPLY 13PIP SIGNAL FLOW 13POWER SUPPLY BLOCK 4SERVICE MODES 38SSB AND PIP VIDEO SIGNAL FLOW 12STANDBY POWER SUPPLY 6TROUBLESHOOTING FLOW CHARTS 43VERTICAL DRIVE CIRCUIT 23VIDEO INPUT 11
INTRODUCTION
The PTV900 series PTV is designed forintroduction in the 2001-2002 model years.The set comes in 43, 50, 55, 60, and 64inch screen sizes. It comes is two versions,single and two tuner. The two tuner versionis equipped with a Side Jack Panel. Bothversions have 181 channel tuning capability.Other features include 7 inch CRTs andComponent input.
Both versions are equipped with a 10 Wattper channel Audio Amplifier. They bothhave two channel line level audio output.The two tuner version has a HeadphoneJack located on the Side Jack Panel.
Page 1
The PTV900 Series Projection TVuses three single color tubes, Red,Green, and Blue. (Figure 1) Theoutput of each tube is projected onto amirror where it is then reflected onto aviewing screen. The Tubes are con-verged so the light from each tubestrikes the same spot on the FresnelLens. The Fresnel Lens equalizesand Concentrates the light to provideequal light uniformity across thescreen. The Mirror is a first surfacemirror type which has the reflectivecoating on the outside of the mirror.To prevent scratching of this surface,always use a soft cotton cloth to cleanit.
PTV900 LIGHT PATH
Figure 1
The Lenticular Lens Screenconcentrates the light from the FresnelLens into narrow strips. (Figure 2) TheLenticular Lens increases contrast byreducing the ambient light with the useof Black Striping. The Prismatic forma-tion of the screen allows for nearly 3Xlight output as compared to a flat screen.Caution should be used when workingwith the screen. Damage can easilyoccur in the form of scratching, or byusing certain chemical screen cleanerswhich can strip the black striping fromthe screen. To clean the screen, useone drop of dish washing detergent ina small bowl of water. (approximately 2liters) Wipe the screen with a soft cottoncloth in the direction of the stripes.
Figure 2 - LENTICULAR SCREEN
Figure 3 - OPTICAL ASSEMBLY
The Three CRT’s are driven by 30KV ofhigh voltage and 15KV of focus voltage.(Figure 3) The Tubes produce a highlyconcentrated light output of a single color.A liquid coolant, made of Glycol, is used totransfer heat from the face of the tube tothe surrounding mechanical assembly. TheC-element lens seals the Coupling fluidwithin the coupler. The C-element lens andCoupling fluid are part of the light path andcontribute to the properties of the opticalsystem.
Page 2
A10 PTV LIGHT PATH PROBLEMS
Look at the edges of the screen. They maybe bowed inward.
PROBLEM - BOTTOM CORNERS DARK
There is no problem with the set. Theviewing angle is too high.
PROBLEM - BOTTOM CORNERS COLORED
PROBLEM- BRIGHT AND DARK LINES ONA WHITE FIELD
Fresnel may be reversed. Carefully removethe fresnel and point the grooves toward theviewer.
PROBLEM - UPPER CORNERS OF THESCREEN DARK
The Fresnel offset is pointing down. Thecenter of the Fresnel should be toward thetop of the screen.
Page 3
POWER SUPPLY BLOCK (Figure 4)
The Line Conditioner circuits produce theRaw B+ for the Standby and Full Powersections. It also provides connection to theAC Neutral for the Full Power section’sStartup voltage.
AC power is fed to the PFC/ LineConditioner. The output of this panel is fedto the Standby and Full Power sections,which are located on the Large Signal panel.
The Standby Power Section beginsoperating as soon as power is applied to theset. This circuit produces a +5 volt and a+3.3 volt standby voltage. The +5 voltstandby voltage supplies power to the FullPower Supply Relay while the +3.3 voltstandby voltage is applied to theMicroprocessor (Painter) located on theSmall Signal Board.
When the Microprocessor pulls the Standbyline Low, the Startup Run Switch is turnedOn, switching the Neutral side of the ACLine to the Full Power Supply. This providesthe Startup voltage for the Full PowerSupply. Once the Full Power Supply isoperating, a 14 volt supply is generated toprovide operating voltage to the primary sideof the Full Power Supply. The Full PowerSupply provides a 130 volt supply for theScan circuits, a plus and minus 32 voltsupplies for the Convergence circuits, a +15volt supply for the Scan supply, a +15VSSBsupply for the Signal circuits, and aAMP_VCC supply of 36 volts for the AudioAmplifier circuits.
The Standby, Full power startup, and Fullpower circuits are located on the LargeSignal Board.
FIGURE 4 - POWER SUPPLY BLOCK
Page 4
LINE CONDITIONER PANEL (Figure 5)
AC line voltage is connected to 1108, Pins1 and 4. The ac is fused by 1000 andthen fed to three line chokes, 5000, 5001,and 5005. The AC Mains voltage isapplied to bridge 6000 and filtered by 2110to produce the Main B+ voltage. The ACis also connected to bridge 6001 toproduce RAWSTBY voltage for theStandby Section of the power supply. Thiscircuit is fused by 1004. Startup voltagefor the Full Power Section is taken fromthe Neutral side of the AC and fed to theFull Power Section on the Large SignalPanel through resistor 3300.
All of these voltages are present when ACvoltage is applied to the set.Approximately 160 volts dc should bepresent between Pins 3 and 5 of connector1100. The same voltage should bepresent between Pins 6 and 8 of 1100 forthe Standby section.
In the connection between the LineConditioner panel and the Large SignalBoard, there are two HOT grounds,GND_HA and GND_C. The two groundare connected together by the Choke5106. An open 5106 would cause the FullPower supply not to operate. Whentroubleshooting, one could be mislead byhaving the voltmeter on the wrong ground.
Page 5
FIGURE 6 - AC INPUT AND LINE CONDITIONER
To Large Signal Panel
STANDBY POWER SUPPLY (Figure 6)
The Standby Power Supply provides 3.3 and5 volt standby voltages to the set. WhenAC voltage is applied to the set, RAWSTBYis developed and applied to the Standbyregulator 7211 through Pins 2 and 4 of theStandby transformer 5202 to Pin 5. TheStartup voltage is developed by chargingcapacitor 2283 through the internal startupresistor Rs. When 2283 is charged to 5.7volts, the IC switches to the internal supply.Power is now supplied by the charge onCapacitor 2283. The Pulse WidthModulator will drive the internal switch todrive the Standby transformer 5202. The ICwill continue to drive the transformer until thecharge on 2283 falls below 4.7 volts.Capacitor 2283 will again be charged by theinternal resistor and process will repeatitself. Voltage is developed from the HOTsecondary winding on Pin 5. This voltage isrectified by 6207 to produce operatingvoltage for the HOT secondary. Voltagefrom Pin 9 is rectified by 6231 to produce
the 3.3 volt Standby voltage. Voltage fromPin 10 is rectified to produce the +5VSTBYvoltage. When the 3.3 volt Standby voltagehas reached the correct level, it will turn theShunt Regulator 6205 On. This drives theOpto-isolator 7213, which switches the HOTsecondary operating voltage to Pin 4 of 7211through resistor 3287. Pin 4 of 7211 willstay at a constant 5.7 volts to provide theoperating voltage for the IC. The Zenerinside 7211 keeps Pin 4 at 5.7 volts.Regulation is accomplished by the ShuntRegulator 6205, Opto-isolator 7213, and theinternal current sensing resistor of 7211.This circuit also produces a Reset voltagevia 7209 and 7208.
Troubleshooting
If the 3.3 volts Standby voltage is notpresent, check Pin 5 of 7211. If this voltageis not changing when observed with anoscilloscope, check Capacitor 2283. If thevoltage is changing, check the Feedbackcomponents, 6205 and 7213.
FIGURE 6 - STANDBY POWER SUPPLY
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FIG
UR
E 7 - F
ULL P
OW
ER
SU
PP
LYP
age 7
FULL POWER SUPPLY (Figure 7)
When the set is turned On, the Main SwitchMode power supply is turned On. Thissupply produces the +130 volt, +32 volt, -32volt, two +15 volt, and Audio supplies.
Startup
When the On/Off line goes Low, transistor7309 is turned Off, turning transistor 7300On. This switches relay 1305 On. Startupvoltage from the neutral side of the ACmains will charge capacitor 2303 to 14.5volts, which will overcome the undervoltagelockout of IC 7302. After the Soft Startcapacitor 2443 charges, the oscillator insidethe IC will turn On. Each cycle of theoscillator will set the flip-flop which will causePin 3 to go High. This will turn the FETswitch 7301 On. Raw Main voltage isapplied to the Drain of 7301 through Pins 4and 8 of 5300 from the Line Conditionercircuit. Current through sensing resistors3308 and 3309 will develop a rampingvoltage which is applied to comparator "B"connected to Pin 7. When the voltage onPin 7 reaches the reference voltage of theComparator “C”, the flip-flop will be reset.The voltage on the inverting side ofcomparator "B" is limited to 1 volt.Therefore, the ramp voltage on Pin 7 will notexceed 1 volt. The circuit will continue tooperate until the charge on capacitor 2303falls below 9.4 volts shutting the IC Off.Each time 7301 is turned On, energy isstored in transformer 5300. Voltage from theHOT secondary on Pin 10 is rectified by6301. When the output of this circuit hassufficient energy to maintain 2303 above 9.4volts, the IC then operates in steady state.
Regulation
When IC 7302 develops a normal steadystate of operation, the 130 volt supply issampled by resistors 3324, 3350, 3323, and3322. This sample voltage is then sent to
Shunt regulator 7304, which drives thefeedback opto-isolator 7303. The feedbackvoltage on Pin 14 is then compared with aninternal 2.5 volt reference by comparator"C". Comparator "C" then sets the referencevoltage on the inverting side of comparator"B" to control the On time of the drive at Pin3. If the voltage on Pin 14 increases due tothe 130 volt supply increasing, the On timeof the pulse on Pin 3 will be reduced. If the130 volt supply decreases, the voltage onPin 14 would decrease, causing the On timeof the pulse on Pin 3 to increase. This isused to keep the 130 volt supply at thecorrect voltage. Variable resistor 3322 isused to adjust the 130 volt supply to thecorrect level.
The overvoltage protection circuit of the ICwill shut the IC down if the VCC level on Pin1 exceeds 17 volts.
Troubleshooting
To troubleshoot this circuit, first check theOn/Off line from the Small Signal Panel toensure that it is going Low. Then check forthe presence of startup voltage on Pin 1 ofthe regulator IC 7302. If the IC is workingcorrectly, this voltage will be changing from9.4 to 14.5 volts. If the startup voltage isnot present, check the startup resistor 3300and the bridge rectifier. If the voltage on Pin1 is changing, check the drive signal on Pin3 of 7302. Then check for signal on the gateand drain of 7301. An excessive load on thesecondary, a short on the 130 volt line forexample, would cause the supply to pulsewith little or no voltage on the secondary.
Page 8
12 AND 8 VOLT REGULATORS (Figure 8)
Voltage regulator 7611 produces an 8 voltsupply for the Audio Processor located onthe SSB panel. Regulator 7612 produces a12 volt source for the Video Output circuits
located on the SSM panel. Both of theseregulators are powered by the +15SSBsource from the Full Power Section. Both ofthese regulators are located on the SSMpanel.
FIGURE 8 - 12 AND 8 VOLT REGULATORS
Page 9
5.2 VOLT REGULATOR (Figure 9)
A 5.2 volt source is developed by 7308 and7307. The Pulse Width modulator in 7307drives transistor 7308 to produce the source.This is a Buck Switch type regulator. TheOn time of 7308 determines the charge oncapacitors 2344 and 2352 to produce theoutput voltage. Feedback for regulator is
sampled by resistors 3339, 3340, and 3334which is fed to Pin 5 of 7307. When theFeedback circuit senses a decrease in the5.2 volt supply, the PWM turns 7308 On fora longer period of time, increasing the outputvoltage. This circuit is powered by the 15volt supply from the Full Power Section.This source is fed to the SSB. This circuit islocated on the LSB.
FIGURE 9 - 5.2 VOLT REGULATOR
Page 10
FIGURE 10 - SSM - SIDE I/O VIDEO INPUT
VIDEO INPUT (Figure 10)
Two Composite Video inputs, one SVHSComponent input, and one Y Cr CbComponent input are located on the SSMpanel. The Y Signal is fed to a Y Sharpnesscircuit which is controlled by the DAC 7710.The Component Y Cr Cb signal is then fed to7711 which switches between theComponent input and the RGB signal from
the Convergence circuit. The RGB signalfrom the Convergence circuit displays theConvergence crosshatch pattern during theConvergence Alignment. FB is theblanking signal from the Convergencecircuit which is selected by IC 7712. FB1is the blanking signal from the Gemstarcircuit. If the Y Cr Cb component input isselected, 7712 selects the Y signal for theAV2 input to the SSB. This is to provide
Page 11
Sync to the Signal processor on the SSBwhen the Component input is selected. Syncfor the Component input signal is on the Y orLuminance Component. The DAC, 7710provides the switching for 7711 and 7712.IC 7712 selects V2 if the Aux 2 or SVHSinput is selected. The Chroma signal is feddirectly to the SSB. The Composite Video orYC from the Side Jack Panel is fed directlyto the SSB via the SSM. All of theComposite inputs and YC inputs are also fedto the PIP circuit. The Component Y Cr Cbsignal is only fed to the SSB via the SSM.Therefore, it is not possible to have theComponent input in the PIP window.Selected Composite Video from the SSB isalso output on the Video output jack.
The Front-Detect senses the presence of anSVHS and or Headphone connected to theSide Jack panel. The SVHS Jack andHeadphone jack has normally closedswitches, which are connected to ground. Ifa SVHS cable or Headphone is connected,the internal switch opens changing thevoltage on the Front-Detect line. In thesame manner, the SEL-SVHS-RR_STATUS2line signals the Microprocessor that a cableis connected to the SVHS, Aux 2 connector.
The DAC IC 7710 also has four videoblanking lines on Pins 11, 12, 13, and 14.The BBLK, GBLK, and RBLK blanks theindividual CRT’s during Convergencealignment. The G2SETUP blanks all threeCRT’s when G2SETUP is selected in theService Menu.
SSB AND PIP VIDEO SIGNAL FLOW (Figure 11)
The PTV900 Series Projection TV has twoPIP versions which are the Single Tuner PIPand the Two Tuner PIP. The Main Tuner islocated on the SSM and the PIP Tuner islocated on the PIP panel. All Videoswitching for the main picture is performedon the SSB.
IF from Pin 11 of the Main Tuner, located onthe SSM, is fed to the Saw Filter 1451 on theSSB. The output of the Saw Filter is fed tothe Signal Processor 7301 on Pins 1 and 2.Composite Video from 7301 is output on Pin16 and buffered by 7305 before being sent tothe PIP panel via the SSM in the Two Tunerversion. In the Single Tuner version, Jumper4308 bypasses the PIP module. In the SingleTuner version, Tuner video is still sent to thePIP module in case the Tuner video isselected for the PIP window. In the TwoTuner PIP version, the PIP module selectsbetween the Main Tuner video and the PIPTuner video. Baseband Audio from Pin 27 of7301 is buffered by 7331 and mixed with theMain Tuner video in the Two Tuner version. Inthe Single Tuner version, Baseband Audio isfed to the Audio processor via Jumper 4304.In the Two Tuner version, Baseband Audiofrom the selected video source from the PIPModule is fed to the Audio Processor viaJumper 4307.
Video is then fed to the Bandpass Filter 1333to filter out any Audio component. The Videosignal is then to Pin 24 of 7301 which selectsbetween the selected Tuner Video or selectedAux in Video for the main picture. IC 7401selects between Aux1 , Aux2 and Aux3 for theMAIN-CVBS-EXT-IN. Selected CompositeVideo is the output on Pin 54 and is bufferedby 7421 before being fed to the Comb Filter7405. Y or Luminance on Pin 15 and Chromaon Pin 13 is fed to the YC Switching IC 7407.IC 7407 selects between the output of theComb Filter IC and selected YC input from theSVHS inputs. The selected YC signal is thenfed to the Matrix circuit in 7401 on Pin 21 and20. YUV is then fed to the internal YUVswitch. The YUV Switch selects between theinternal YUV or external YUV from theComponent input jacks. This is an RGBsignal if the Convergence Alignment modehas been selected. Y is the Luminancesignal, U is the B-Y or Cb signal. V is the R-Yor Cr signal.
Page 12
Selected YUV is the output on PIns 40, 45and 46 to the PIP Module via connector0205. The PIP Module then outputs theYUV signal back to the SSB to Pins 39, 47,and 48 of 7301. The signal is then fed to aControl circuit and then to the RGB Matrix.The Matrix is then fed to an RGB outputcircuit. Brightness, Contrast, Color, ColorTemperature, RGB cutoffs, RGB drives, andTint are all controlled inside 7301.
RGB is then output to the SSM and the RGBAmplifiers. The RGB signal is then fed tothe three CRT panels.
The EHTINFO line is sent to the CathodeCalibration circuit to sense changes in BeamCurrent in the CRTs. The CUTOFF line isused to calibrate the Cutoffs and Drives tomaintain the correct White Balance. Thesecircuits are discussed in more detail later.
PIP VIDEO SIGNAL FLOW (Figure 12)
If the PTV is a Two Tuner version, thesecond Tuner is located on the PIP module.IF from the PIP Tuner is fed to SAW filter1901 and then to the Signal Processor 7914.Combined Composite Video and BasebandAudio is output on Pin 7. This signal is fedto 7916 which selects between the output of7914 and Composite Video from the SSB.Selected Video for the Main Picture is outputon Pin 15 and is buffered by 7917 beforebeing fed to the SSB via the SSM. Theoutput on Pin 4 selects between the SSBand PIP Tuner for PIP window signal. Theoutput on Pin 4 is buffered by 7920 and fed
to 7801, which selects between selectedTuner Video and Aux in video. Selected out-put on Pin 15 is buffered and fed to the PIP IC7803. IC 7803 is controlled by the SDA andSCL data lines on Pins 3 and 4. Vertical Syncis fed to the IC on Pin 33 and Horizontal Syncif fed to the IC on Pin 32. The IC digitallyprocess the Video to a PIP window. The PIPwindow is output as YUV and FB to 7919 onPins 6, 7, 8, and 5. YUV from the SSB for theMain Picture is fed to 7919 on Pins 2, 3, and4. IC 7919 inserts the PIP window into theMain Picture signal if a PIP signal is present.YUV is then output on Pins 12, 11, and 10 tothe SSB.
PIP POWER SUPPLY (Figure 13)
The PIP Panel is powered by the 5.2 volt, 8volt, and 33 volt power supplies from theLarge Signal Panel (LSP) via the SSM. The5.2 volt supply is fed to 7891 to produce three3.3 volt supplies for the PIP processing IC.The 33 volt supply is not present in the SingleTuner version.
PIP CONTROL (Figure 14)
IC 7910 provides the switching signals for thePIP Panel. This is IC is controlled by the SDAand SCL (I2C bus) lines from theMicroprocessor. The SEL_TUNER1 andSEL_TUNER2 lines switch 7916 to switchbetween the Tuner Video from the SSB andthe PIP Tuner. Control lines S1, S2 and S3switch 7801 to select between the selectedTuner Video or one of the Aux inputs for thePIP window.
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FIG
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E 11 - S
SB
AN
D P
IP V
IDE
O S
IGN
AL P
AT
HP
age 14
FIG
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E 12 - P
IP V
IDE
O S
IGN
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AT
HP
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FIGURE 13 - PIP POWER SUPPLIES
FIGURE 14 - PIP CONTROLPage 16
CRT DRIVE CIRCUIT (Figure 15)
Red, Green, and Blue drive from the SSBpanel is fed to the CRT drive circuit on theSSM PANEL. Red drive is fed to transistors7600 and 7602. Green drive is amplified by7603 and 7605. An additional amplificationcircuit is added to the Blue circuit to provideadded gain. This is called the Blue Stretchcircuit. This circuit consist of transistors7606, 7607, and 7613.
Transistors 7601, 7604, 7609 provides CRTblanking. In the event of a Sweep failure,the High on the CRT protection line from theHigh Voltage Scan circuit will go Low.Diodes 6602, 6605, and 6610 will will turnthe blanking transistors On.
When the G2SETUP line goes low, diodes6606, 6600, and 6603 are forward biased,blanking drive to the CRT's.
During the Convergence Alignment mode, itis necessary to blank the CRT or CRTs thatare not being adjusted. This isaccomplished by placing a Low on the RBLK(Red Blanking), GBLK (Green Blanking), orthe BBLK (Blue Blanking).
The Red, Green and Blue Drive is fed to theGreen CRT panel along with a 12 volt bias.Red and Blue drive from the Green CRTpanel is routed to their respective CRTs.Filament voltage and the 240 volt CRT drivevoltage from the Scan High Voltage panel isfed to the Green CRT panel.
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FIG
UR
E 15 - C
RT
DR
IVE
CIR
CU
ITP
age 18
GREEN CRT PANEL (Figure 16)
Green Drive from the SSM is fed totransistor 7802 on the Green CRT panel.The other Colors are fed to their respectiveCRT panels via the Green CRT panel. The12 volt source turns transistor 7801 On toswitch drive the Cathode of the CRT.Transistor 7801 is an impedance matchingcircuit to connect the low output impedanceof 7802 to the high input impedance of theCRT. CRT drive is fed to transistor 7805 toproduce IKG feedback. The IKG, IKR, andIKB feedback is combined on the SSM. Thisis part of an automatic CRT bias level loop.The CRT is powered by the 240 volt sourcefrom the Large Signal panel. Focus and G2voltage is provided by the Focus/G2 block.Filament voltage is provided by theHorizontal output circuit on the Large Signal
panel. The Red and Blue CRT panels havesimilar circuits.
Troubleshooting
If there is no Picture present on the set, butAudio is present, it can be assumed that thePower Supply is working correctly. If G2voltage is present, it can be assumed thatthe High voltage circuits are working. The240 volt supply, 12 volt supply, and RGBdrives should be checked next. The CRTboards can be interchanged between CRTsto determine if the problem is with the CRTor the CRT drive panel. At least one of theCRTs must be connected to produce RGBdrive. If none of the CRTs are connected acalibrating pulse at the Vertical rate will bepresent on the CRT drive lines.
FIGURE 16 - GREEN CRT PANEL
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FIG
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E 17 - C
UT
OF
F A
ND
CA
TH
OD
E C
ALIB
RA
TIO
NP
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CUTOFF AND CATHODE CALIBRATION(Figure 17)
The Cathode Calibration circuit in 7301continuously adjust the RGB drives to keepthe correct White Balance for the picture.The IKB Blue CRT Feedback signal is fed to7615. The bias for 7615 is set by 3666,3663, and 3664. The output of 7615charges 2625, driving 7616. Thecombination of the ABL voltage and internalresistance of 7616 sets the CathodeCalibration voltage on Pin 34 of 7301, SignalProcessor. This signal is also used toensure that there are no Brightness changesdue to changes in Beam Current. It is alsoconnected to the Vertical Drive circuits toensure that the Picture Height does notchange due to changes in Beam Current.
IC 7301 also has a Beam Current Limiting
and Peak White Limiting circuit. This signalis monitored via the BLKIN input on Pin 30.This circuit is driven by the CUTOFF linewhich is a combination of the IKR, IKG, andIKB CRT feedback signals. Capacitors 2622and 2336 form a Low Pass filter to preventthe circuit from reacting to the HighFrequency content of the Video signal.
When the Set is turned On, a Calibrationsignal is output on the RGB lines. Thissignal is fed back on the IKR, IKG, and IKBlines. When this signal reaches the correctamplitude, the RGB output circuit in 7301switches On to output the Video signal. Thissignal is a stair-step signal at the verticalrate and is fed to the CRTs during the verti-cal blanking period. During Turn Off, thissame signal is applied to the CRTs to ensurethat the CRTs are discharged.
Page 21
FIG
UR
E 18 - H
OR
IZO
NTA
L DR
IVE
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age 22
HORIZONTAL DRIVE CIRCUIT (Figure 18)
Horizontal Drive from the SSB Panel is fedto buffer transistor 7803. Transistor 7803then drives the Horizontal Driver transistor7801. Horizontal drive is then fed to theLine output transistor 7802. Transistor 7802drives the three Horizontal Yokes and theScan transformer 5801. The Scantransformer produces a 240 volt supply forthe CRT drive circuits, a Filament drive forthe CRT's, a plus and minus 13 volt supplyfor the Vertical drive circuit. It also producesa 32 volt supply for the beam limiter circuit inthe High Voltage circuit. The output of theHorizontal Output transistor 7802 is also fedto buffer transistors 7800 to produce aHorizontal feedback pulse to the SSB Panel(HFB). The 170 volt Pulse is monitored bythe Sweep Failure detection circuit. If thiscircuit detects a loss of Horizontal drive, theHigh Voltage is shut Off.
Drive for geometry correction from the SmallSignal panel on the E_W line drivestransistors 7553, 7551, and 7552. Thiscircuit drives the return side of the HorizontalYokes to provide Horizontal corrections tothe geometry. Geometry correction drive,E_W, is also fed to transistor 7830 whichproduces drive for the Dynamic Focus, LV.The Dynamic Focus voltage is connect tothe Focus/G2 block to provide edge focus
correction. The Horizontal component to theDynamic Focus is added in transformer5802.
VERTICAL DRIVE CIRCUIT (Figure 19)
Vertical Drive from the Small Signal panel(FDRVP and VDRV) is fed to the VerticalOutput IC 7550. This circuit is powered by a+13 volt supply connected to Pin 8 and a-13 volt supply connected to Pin 6 which aresupplied by the Horizontal Drive circuit. Pin5 of 7550 provides drive for the threeVertical yokes. Vertical drive feedback fromthe return side of the yokes is fed back toPin 2 of 7550. Vertical sync (VPUL) for theSweep Failure Detection circuit is output onPin 4 of the IC. Output from Pin 7 isbuffered by transistor 7590 to produce aVertical Sync pulse (VFB) for the SSB.
A failure in this circuit would cause the HighVoltage to shut down. A problem in thiscircuit could be caused by a loss of drivefrom the SSB or a failure in the HorizontalSweep circuit. An open Yoke connectionwould also cause the Vertical drive from theIC to shut down.
When troubleshooting this circuit tocomponent level, the CRTs should beunplugged to prevent damage to them.
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FIG
UR
E 19 - V
ER
TIC
AL O
UT
PU
TP
age 24
FIG
UR
E 20 - H
IGH
VO
LTAG
E A
ND
SH
UT
DO
WN
Page 25
HIGH VOLTAGE AND SHUTDOWN(Figure 20)
The High Voltage circuit in the PTV900series chassis is contained in an integratedHigh Voltage Module. This circuit ispowered by the 130 volt source from the FullPower supply. The Dag line from the CRT'sis connected to 1574 and to Pin 1 of theHigh Voltage module. This line along withthe current sense line from Pin 2 isconnected to the Beam Limiter transistors7905 and 7910. This provides feedback tothe RGB output circuit in IC 7301 located onthe SSB panel to make minor changes inbrightness and vertical height.
When the set is turned On, 130 volts isapplied to Pin 10 of the High Voltagemodule. Transistor 7500 acts as an ORgate to detect the failure of Vertical Sweep(VPUL) or Horizontal Sweep (170V Pulse).When these pulses are present, 7500 isturned Off, allowing 7501 to turn On. Thiswill apply approximately 7.5 volts dc to Pin 8of the High Voltage module, turning it On.
The High Voltage module produces 15 kVfor the Focus/G2 block and 30 kV for theCRT's. This also places a High on theCRT_PROT line, allowing the CRT drivecircuits to turn On. If Horizontal or Verticaldrive should fail, CRT drive and High Voltagewill be shut off to protect the CRT's. Afailure is either drive will cause 7500 to turnOn, turning 7501 Off, removing the 7.5 voltsfrom Pin 8 of the High Voltage module,shutting it Off. The CRT_PROT line will alsogo Low, shutting the RGB amplifiers to theCRT panels Off.
In the case of Overcurrent, the voltage onPin 2 of the High Voltage module will drop,turning transistor 7909 On, turning 7908 On,latching 7907 and 7908. This will removethe 7.5 volt turn On voltage at Pin 8 of theHigh Voltage module, turning it Off. Duringturn On, transistor 7906 is biased Off whilecapacitor 2913 charges. This prevents theshutdown latch from turning On while theHigh Voltage module is turning On.
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FIG
UR
E 21 - C
ON
VE
RG
EN
CE
BLO
CK
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DIGITAL CONVERGENCE CIRCUIT (Figure21)
CRT's and Yokes are not linear devices.Therefore, a convergence circuit isnecessary to align the beams of all threetubes over the entire screen. TheConvergence panel is powered by a +32volt, a -32 and a +15 volt supply from thePower Supply panel. A Horizontal Sync (HPUL) and a Vertical Sync (V PUL) from theScan High Voltage panel keeps theConvergence Correction waveformssynchronized to the deflection system. TheSDA and SCL lines on Pins 32 and 34 allowthe microprocessor on the SSM Panel tocommunicate with the microprocessor on theSSB Panel. During the Convergencealignment mode, the crosshatch pattern isgenerated in the Convergence circuit. Red,Blue, Green, and Fast Blanking are fed tothe Interface panel and then to the SmallSignal panel to be inserted into the videodrive.
There are two plus 5 volt regulators, and a-5 volt regulator in the convergence circuit.These are fed by the plus 15 volt SSB, andthe -32 volt supplies from the Large SignalPanel. The 5 volt supply feeds the micro-processor while the 5VA supply feeds theDigital to Analog converter IC's. The Plusand minus 32 volt supplies provide power tothe output IC's 7012 and 7014.
The Convergence panel has a phase-lockedloop oscillator which produces a 13.59 MHzsignal. (Figure 30) This signal is phaselocked to the 15734 Hz NTSC HorizontalBlanking pulse (HPUL). This signal is usedas the system clock which is used by theconvergence spline processor (CSP) and thethree digital to analog converters (DACS).Therefore, the convergence correctionwaveforms are synchronized to thedeflection system of the television set.Operational amplifier 7001 is used as aninverting two pole Sallen_Key filter which
acts as the loop filter. Transistor 7000 and7001 make up the oscillator.
When the set is turned On, themicroprocessor on the Small Signal panelreads the data stored in 7007 on theConvergence panel via the I2C bus. Thisinformation contains the x-y coordinates forthe 35 alignment points of each color visibleon the screen during convergence set upalong with other register settings used by thecsp.
The csp uses fourth order polynomialequations called quadric splines in thealgorithm to convert the data of the 35 (7horizontal by 5 vertical) alignment points into24 points per horizontal 486 vertical lines forNTSC. The resulting digital data is suppliedto 7009, 7011 and 7010, the three twochannel dacs which convert the digital datainto analog convergence correction signalsfor red, green, and blue horizontal andvertical. The csp outputs are approximately1 to 2 volts peak to peak with a 2.5 volt dcoffset. The csp also supplies a 375 KHz 5volt peak to peak ws or word select signal toselect the proper channel on the dac forhorizontal or vertical.
The Convergence correction waveforms maybe disabled for set up procedures byshorting connector 1005.
The output of the dac's are amplified andfiltered by IC200, IC201, and IC202 beforebeing fed to the Yoke drive amplifiers.
If for some reason the set needs to beconverged in the field, the csp generates across hatch pattern with an intensified cross.Control for 7003 csp is done by themicroprocessor on the SSB Panel. The R,G, B, Fast Blanking, and Intensity signalsused to display the pattern are output onPins 29, 30, 31, 25, and 26 on 7003.
Page 28
AUDIO SIGNAL FLOW
All of the Audio switching is done on theSSB Panel. (Figure 22) Baseband AudioSIF1 is fed to Pin 50 of 7651, AudioProcessor. Two Aux signals from the RearJack Panel and one channel from the SideJack Panel can be fed to the switch insidethe IC. An AVC (Automatic VolumeCorrection) circuit in the IC corrects forchanges in audio levels from differentprogram sources. When the AVC circuitturned On, a fixed output of -18 dB will bemaintained for an input varying from -24 dBto 0 dB. That is with an input level of 0 dBbeing 2 volts rms and the output level of 0dB being 1.4 volts rms. Pins 21 and 20 arethe outputs to the Audio Amplifier. Pins 18and 17 are output to the HeadphoneAmplifier. The Audio Amplifier andHeadphone are all tied to an internal volumecontrol and Muting circuit. The SC1_OUT_Rand SC1-OUT-L are fixed line level outputswhich are fed to the Audio Output on theRear Jack Panel. The Aux out, Headphone,or Speaker output can be driven by differentsources as selected by the user. Forexample, the user can be listening to theAudio from the main picture through thespeakers and listening to the PIP Audiothrough the Headphones.
Audio from 7651 on the SSB Panel is fed to
the Audio Amplifier on the SSM Panel.(Figure 23) The Audio is input on Pins 7 and11 and output on Pins 4 and 2. The IC ispowered by a 36 volt AMP-VCC supply fromthe Full Power Supply. When theMicroprocessor on the SSB senses that allthe supplies are present, the Sound-Enableline goes High, turning transistor 7401 On.This causes Pin 5 of 7402 to change from36 volts to 28 volts. If the +15 volt supplygoes Low, transistor 7405 will turn On,turning transistor 7410 On, which will turntransistor 7401 Off. Pin 5 of 7402 will thengo to 36 volts, which will Mute the Audio.
Left and Right Headphone Audio is fed to7403 and then to the Headphone Jack onthe Side Jack Panel. Sub-woofer audio isbuffered by 7415 before being fed to theRear Jack Panel. The Side Jack panel isonly used in the two Tuner version.
Left and Right Monitor output audio from theSSB is fed to output jack located on theSSM.
Page 29
FIG
UR
E 22 - A
UD
IO IN
PU
T A
ND
SW
ITC
HIN
GP
age 30
FIG
UR
E 23 - A
UD
IO A
MP
LIFIE
RP
age 31
MICROPROCESSOR (Figure 24)
The Microprocessor (Painter), 7064, islocated on the SSB Panel. The Usercommunicates with the Microprocessor viathe Remote Control or the Front Keyboard.The Keyboard is a resistor latter whichproduces a voltage level change on Pin 5when the User makes a selection. TheRemote Receiver is located on the FrontPanel. The Program to run the set isloaded in the ROM in the Microprocessor.User settings, Geometry settings, OptionsCodes to identify the set, Error Codes, Tunerand Audio settings, and Cutoff settings arestored in the Memory IC 7066. TheMicroprocessor communicates with theMemory IC via an I2C buss. TheMicroprocessor communicates with the restof the set via to I2C busses on Pins 82, 81,
and 84, 83. Additional communications withthe set is done through six analog controllines, STAND-BY, SEL-MAIN-FRNT-RR,SEL-MAIN-R1R2, SOUND-ENABLE, SYS1AND SYS2. The STAND-BY line goes Lowto turn the set On. On Screen Display(OSD) is output on Pins 46, 47, and 48 ofthe IC. Sync for this display is input on Pins53 and 55.
I2C BUS (Figure 25)
The Microprocessor SDA and SCL linescommunicate with seven devices. They arethe 7301 Signal Processor, 7651 AudioProcessor on the SSB. On the SSM the linecontrols the Main Tuner and 7710 ControlDAC. The line then goes to the PIP Panelwhere it controls the Tuner, PIP Processor,and Control IC.
Page 32
FIG
UR
E 24 - M
ICR
OP
RO
CE
SS
OR
Page 33
FIG
UR
E 25 - I2C
BU
S
Page 34
FIGURE 26 - KEYBOARD AND IR RECEIVER
KEYBOARD (Figure 26)
The Keyboard on the front of the set is madeup of a resistor ladder. Each selectionswitch causes a different voltage to be
developed on the control line. The IRReceiver is also located on the FrontKeyboard. Pressing any button on the frontof the set will turn the set On.
Page 35
FIG
UR
E 27 - W
IRIN
G IN
TE
RC
ON
NE
CT
Page 36
BOARD LEVEL TROUBLESHOOTING(Figure 27)
The PTV900 series projection TV isdesigned for modular level repair. To makean accurate determination of which moduleis defective a Voltmeter and Oscilloscopeare necessary.
Dead Set
The Standby LED on the front of the setshould come on as soon as power is appliedto the set. If the Standby LED is lit, theStandby Power supply is working.
If there is no Standby LED, check theStandby B+. This should be checked usingthe GND_HA as a ground reference. This isa HOT ground. An isolation transformershould always be used whentroubleshooting any electronic product.This voltage should be approximately 160volts dc. If this voltage is present, then the+3.3 volt supply to the SSM should bechecked. This voltage can be checked onPin 10 of connector 1518 on the LSB. If theStandby voltage is missing at this point, thenthere is a problem on the LSB (Large SignalBoard). The Microprocessor is located onthe SSB, which plugs in to the SSM. The3.3 volt supply to the SSB can be checkedon Pin 40 of connector 1026. If this voltageis present, the problem is on the SSB. If thisvoltage is missing from Pin 40, there is aconnection problem on the SSM.
If the Standby LED is working, the Standbyline should go Low to turn the Main PowerSupply On. This can be checked on Pin 9 of1518. If the line goes Low, then check the130 volt supply on Pin 2 of 1518. If the 130volt supply is not present, check the MAINB+ to the LSB from the Filter Panel. Thisvoltage should be checked relative toGND_C. This is a HOT ground. If theMAIN B+ is present, and the 130 volt supplyis missing, the problem is on the LSB. If the
130 volts supply is present, the High Voltage(EHT) should be checked. An easy was todetermine if High Voltage is present, is tocheck the Screen Voltage (G2). Follow anyof the G2 lines from the Focus/G2 Block toits respective CRT and check the voltagethere. This voltage will be approximately240 volts. If High Voltage is missing,Horizontal and Vertical drive to the LSBshould be checked. Horizontal Drive can becheck on Pin 1 of connector 1520. VerticalDrive can be checked on Pin 5 of connector1520. These signals are generated on theSSB which plugs into the SSM. HorizontalDrive can be checked on Pin 55 ofconnector 1026. Vertical Drive can bechecked on Pin 52 of connector 1026. IfHorizontal and Vertical Drives are being fedto the LSB, the problem is on the LSB.
No Picture
If OSD (On Screen Display) is present, it canbe assumed that the Power Supplies are allworking, Video Drive Circuits are working,and CRTs are working. If no OSD ispresent, check the Red, Green, and Bluedrive to the CRT panels on connector 1083.The +12 volt supply should also be checked.If a Pulse at the Vertical rate is present onthese lines, check to see if the same Pulseis present on the IKR, IKG, and IKB lines. Ifit is not, the problem is on the CRT panels.If no signal is present on the RGB lines,check R-CRT, G-CRT, and B-CRT lines onconnector 1026. If no signal is present atthat point, change the SSB.
No Audio
If no Audio is present, check the AudioPower supply on Pin 11 of connector 1017on the SSM panel. This should beapproximately 36 volts. If this voltage ispresent, check the Audio lines and Sound-Enable line from the SSB. If Audio ispresent and the Sound-Enable line is 5 volts,the SSM should be repaired or replaced.
Page 37
SERVICE MODES
Service Default Mode (SDM)
The Service Default Mode (SDM) is a technical aid for the service technician. The ServiceDefault Mode (SDM) establishes fixed, repeatable settings of customer controls, which allowconsistent measurements to be made. The SDM also initiates the blinking LED procedureand, if necessary, overrides the 5V protection. This mode also allows the operating hours ofthe set, the software version, and error codes to be read.
The SDM places the set in the following pre-defined conditions:· Tuning frequency set to Channel 3.· Volume level set to 25% (of the maximum volume level).· Other picture and sound settings set to 50% (mid-range).The following functions are turned off in SDM (and after leaving SDM):· Timer· Sleep timerThe following functions are disabled during SDM (and enabled after leaving SDM):· Parental lock
All other controls operate normally.
Entering Service Default Mode
To enter the Service Default Mode, press the following key sequence on the remote controltransmitter:
0-6-2-5-9-6-MENUDo not allow the display to time out between entries while keying the sequence.Upon entry into the Service Default Mode, the letters "SDM" will be displayed at the upperright corner of the screen.
Pressing the "MENU" button on the remote control switches between the SDM and thenormal user menus (with the SDM mode still active in the background) Run timer, softwareidentification, and error buffer
Press the Index or Status button on the remote control to toggle the OSD (except "SDM") ONand OFF to prevent the OSD from interfering with measurements and oscilloscopewaveforms.
Access to SAMTo access the Service Alignment Mode while press the "VOLUME +" and "VOLUME -"buttons on the local keyboard simultaneously for at least 4 seconds.
The Blinking LED ProcedureThe contents of the error buffer can also be made visible through the "blinking LED"procedure. This is especially useful when there is no picture.
NOTE: If errors 1, 2, 3, or 4 occur the LED ALWAYS blinks indicating the last error which
Page 38
occurred, even if the set is NOT in service mode. When the SDM is entered, the LED willblink the number of times equal to the value of the error code. Upon entry into the SDM, theLED will blink the contents of the error-buffer.
Error-codes greater than/equal to 10 are shown in the following manner:
A long blink of 750 milliseconds indicating the decimal digit, followed by a pause of 1500milliseconds. The LED will then blink the number equal to the error code. When all error-codes are displayed, the sequence is finished with an LED display of 3 seconds. At this pointthe sequence will begin again.
Example:Error code position 1 2 3 4 5 Error buffer: 12 9 6 0 0
After entering SDM: The sequence will begin with 1 long blink of 750 milliseconds, then pause 1500 milliseconds,then blink twice (indicating error code 12), then the LED will pause for 3 seconds, then blink 9times (indicating error code 9), then the LED will pause for 3 seconds, then blink 6 times(indicating error code 6), then pause 3 seconds and blink for 3 seconds again, ending theblinking sequence.
Exiting Service Default ModeTo exit the Service Default Mode, press the Power button.
Service Alignment Mode (SAM) (See Figure 28)IntroductionThe Service Alignment Mode (SAM) is used to align the set and/or adjust the option settingsand to display/clear the error code buffer values.
Entering Service Alignment ModeTo enter the Service Alignment Mode (SAM), press the following key sequence on the remotecontrol transmitter:
0-6-2-5-9-6-INDEX or STATUSDo not allow the display to time out between entries while keying the sequenceIt is also possible to enter the Service Alignment Mode by pressing the "VOLUME +" and"VOLUME -" key on the local keyboard simultaneously for at least 4 seconds when the set isin SDM.
Exit SAM:To exit the Service Alignment Mode, press the Power button.
SAM Menu ControlMenu items may be selected using the cursor UP/DOWN keys. The selected item will behighlighted. · When not all menu items will fit on the screen, pressing the cursor UP/DOWNkeys on the remote transmitter will display the next/previous menu items.With the cursor LEFT/RIGHT keys, it is possible to: · (de)activate the selected menu item
Page 39
(e.g. GEOMETRY) ·change the value of the selected menu item ( e.g. VER-SLOPE ) activate the selected submenu (e.g. SERV-BLK)
Access to normal user menu:
Pressing the "MENU" button on the remote control switches between the SAM and the nor-mal user menus (with the SAM mode still active in the background). Pressing the "MENU"key in a submenu will return the screen to the previous menu.
Explanation of the Error code buffer:
The error code buffer contains all errors detected since the last time the buffer was erased.The buffer is written from left to right. When an error occurs that is not yet in the error codebuffer, the error code will appear at the left side and all other errors shift one position to theright.
Error code table
Code Number Error Description
00 Not an Error01 Too high I-beam or East/West protection02 Vertical protection03 X-Ray protection04 5 volt protection05 - not used06 General IIC error07 BC loop not stabilized08 Bocma TDA888X IIC error09 Bocma IC 8v failure10 NVM IIC communication error11 Wrong NVM type12 Microp internal RAM error13 Main tuner IIC failure14 Sound IC failure15 SRAM test failure16 PIP Tuner IIC failure17 ECO Pip IC or DW Pip IC failure18 I/O expander I2C error19 Gemstar Guide Plus board20 V-chip located on the DW Pip21 Non-Volatile clock22 Incredible picture (YUV) CR23 Bocma DoubleWindow TDA888X error24 - not used25 - not used
Page 40
Code Number Error Description
26 - not used27 Virtual Dolby28 - not used29 - not used30 CSP i2c error31 CSP NVM i2c error32 CSP NVM error - not valid data33 CSP dac i2c error
Customer Service Mode (CSM)
All PTV900 sets are equipped with the "Customer Service Mode" (CSM). CSM is a specialservice mode that can be activated and deactivated by the customer, by request of the ser-vice technician/dealer in order to identify the status of the set. This CSM is a 'read only'mode, therefore modifications in this mode are not possible.
The Customer Service Mode can be switched on by pressing the MUTE button on the remotecontrol and any key on the local keyboard (Channel Up, Channel Down, VOL +, VOL -) onthe TV simultaneously for at least 4 seconds.
When the CSM is activated: Picture and sound settings are set to nominal levels. Modes thatinterfere with the behavior of the set are switched off (sleep timer, auto standby, etc.)
Exit the Customer Service Mode.The Customer Service Mode will be switched off after pressing any key on the remote control(except "Channel Up" or "Channel Down") or by switching off the TV set by pressing thePower button on the remote control or the local keyboard.
Exiting CSM resets the TV set back to its initial values.
Page 41
FIG
UR
E 28 - S
ER
VIC
E A
LIGN
ME
NT
MO
DE
Page 42
START DOES THE SETTURN ON
DOES THE SETHAVE A PICTUREYES IS THE COLOR OKYES IS AUDIO OKYES
NO
IS THE RED LEDON
DOES THE LED TURN OFFWHEN THE POWER BUTTON
IS PRESSED
YES
IS THE LEDFLASHINGNO YES
USE COMPAIR ORFLASHING LED TO
READ ERROR CODES
IS PIN 19 OF 1026 ONTHE SSM PANEL 3.8VOLTS OR 0 VOLTS.
NO
REPLACE THE SSB
3.8 VOLTS
IS 0 VOLTSPRESENT ON PIN 8
OF 1018 ON THESSM PANEL
0 VOLTS
REPLACE THE SSMPANEL OR CHECK7303 TO REPAIR
YES
REPAIR OR REPLACETHE LSBNO
THE PROBLEM IS IN THERESET CIRCUIT. CHECK
7209, 7208, AND RELATEDCOMPONENTS.
REPAIR
IS > 140 VOLTSPRESENT ON PIN 3
OF 1500 ON THELSP
YES
REPAIR OR REPLACETHE LINE
CONDITIONER PANEL
NO
IS 130 VOLTS PRESENT ONTHE CATHODE OF 6305 AFTER
THE POWER BUTTON ISPRESSED
YES
SSB PANEL
YES
IS THE RESISTANCE TOGROUND ON THE 130
VOLT LINE > 10K
NOCHECK FOR SHORTON THE 130 VOLTLINE. PROBABLE
7802.
NO
A
YES
BNO
D
E
NO
F
NO
GNO
IS CONVERGENCEOK?
YES
HNO
CALL YOURTECHNICAL HELP
CENTER
YES
Page 43
A DOES PIN 9 OF 1018 GO LOWWHEN THE POWER BUTTON
IS PRESSED
DOES RELAY 1305ENERGIZE WHEN THE
POWER BUTTON ISPRESSED
DOES THE VOLTAGE ON PIN2 OF 1014 CHANGE WHENTHE POWER BUTTON IS
PRESSED
NOKEYBOARD ORREMOTE RECEIVER
NO
SSB ORCONNECTIONS ONTHE SSM PANEL
YES
YES
CHECK 7300 AND 7309ON THE LSP
NO
IS PIN 1 OF 7302CHANGING BETWEEN9.4 AND 14.5 VOLTS
YESCHECK 6000 AND 3300 ONTHE LINE CONDITIONER
PANEL AND 5315 ON THELSP
NO
IS A DRIVE SIGNALPRESENT ON THE
GATE OF 7301
YES
CHECK 7302, 7301,AND RELATEDCOMPONENTS
NO
IS A DRIVE SIGNALPRESENT ON THE
DRAIN OF 7301
YES
CHECK 7301, 1300 ANDCONNECTIONS ON 5300NO
CHECK FEEDBACK CIRCUIT AND 15VOLT LINE FOR SHORT. CHECK 1302,
7303, 7302, 7304, AND RELATEDCOMPONENTS.
YESB IS 3.3 VOLTS PRESENT ON PIN10 OF CONNECTOR 1018 ON
THE SSM PANEL?
IS 5 VOLTSPRESENT ON PIN
12 OF 1018?YES
CHECK 6204 AND RELATEDCOMPONENTS ON THE LSB
PANEL.
NO
IS 3.3 VOLTS PRESENT ONPIN 40 OF CONNECTOR 1026
ON THE SSM PANEL?
YES
REPAIRCONNECTIONS ONTHE SSM PANEL.
NO
IS 5 VOLTS PRESENTON PIN 36 OF 1026 ON
THE SSM PANEL?YES REPLACE THE SSB
PANEL.
YES
CHECK CONNECTIONSON THE SSM PANEL.
NO
C
NO
Page 44
CIS APPROX 160 VOLTS DC
PRESENT ON PIN 8 OFCONNECTOR 1500 ON THE LSB?
USE PIN 6 AS GROUND
NO
IS 3.3 VOLTS PRESENTON THE CATHODE OF
6231?
YES
CHECK CONNECTIONSON THE LSB PANEL. YES
IS > 140 VOLTSPRESENT ON PIN 5
OF 7211?NO
CHECK 7211, 3216,AND RELATEDCOMPONENTS.
NO
IS PIN 5 OF 7211PULSATING?
YES
CHECK 7213, 6207,6205, AND RELATED
COMPONENTS.YES
CHECK 7211 AND 2283.
NO
EIS OSD (ON
SCREEN DISPLAYPRESENT?
SSB PANEL OR PIPPANEL
YES
IS HIGH VOLTAGE PRESENT?HIGH VOLTAGE CAN BE
CHECKED BY MEASURING FORTHE PRESENCE OF SCREEN
VOLTAGE.
NO
IS > 6.5 VOLTS PRESENT ONPIN 8 OF THE HIGH VOLTAGE
MODULE?
NO
REPLACE THE HIGHVOLTAGE MODULE.
YES CHECK 7500, 7501, 7907,7908, 7909, 7906, AND
RELATED COMPONENTS.NO
IS RGB DRIVE PRESENT ONPINS 56, 57, AND 58 OF 1026 ON
THE SSM PANEL?
YES
SSB OR PIP/DWPANEL. NO
IS RGB DRIVE PRESENT ONPINS 3, 5, AND 7 OF 1083 ON
THE SSM PANEL?
YES
CHECK RGB DRIVECIRCUITS ON THE SSM
PANEL.
NO
IS 12 VOLTS DCPRESENT ON PIN 6 OF
1083 ON THE SSMPANEL?
YES
CHECK CRT PANELS. YES
CHECK 7612 AND 3646ON THE SSM PANEL.
NO
CHECK 6001, 1004, 3009,3010, 1000, AND RELATED
COMPONENTS.
Page 45
DERROR 2VERTICAL
PROTECTION
CONNECT A SCOPETO PIN 5 OF 1020. SETTHE SCOPE TO READ
VERTICAL DRIVE.TURN THE SET ONWHILE OBSERVING
THE SCOPE.
IS THE VERTICALDRIVE WAVEFORM
PRESENT?
SSB PANEL ORCONNECTIONS ONTHE SSM PANEL.
NO
CHECK 7550, +13 VOLT, AND -13 VOLTSUPPLIES ON THE LSB. ALSO CHECK
YOKE CONNECTIONS.YES
CONNECT A SCOPETO PIN 1 OF 1020 ON
THE SSM PANEL.TURN THE SET ONWHILE OBSERVING
THE SCOPE.
ERROR 9BOCMA IC
8 VOLT FAILURELOSS OF LINE DRIVE
IS HORIZONTAL DRIVEPRESENT WHEN THE SET IS
TURNED ON?
SSB PANEL
NO
CHECK 7803, 7801, 7802, AND RELATEDCOMPONENTS ON THE LSB PANEL.YES
CHECK THE ERRORCODE LIST FOROTHER ERROR
CODES.OTHER ERRORS
Page 46
F IS YUV PRESENT ON PINS1, 4, AND 5 OF 0205 ON
THE SSB PANEL?
SSB PANEL
NO
IS YUV PRESENT ON PIN 6, 8,AND 9 OF 0205 ON THE SSB
PANEL?
YES
PIP PANEL
NO
IS RGB PRESENT ON PINS56, 57, AND 58 OF 1026 ON
THE SSM PANEL?
YES SSB PANELNO
IS RGB PRESENT ON PINS 3,5, AND 7 OF 1083 ON THE
SSM PANEL?
YES
RGB DRIVE CIRCUITSON THE SSM PANEL.NO
CHECK GREY SCALE, G2,ALIGNMENTS.
SSB COLOR PROCESSING.
YESG IS APPROX 36 VOLTS
PRESENT ON PIN 3 OF7402?
CHECK 6309 ANDRELATED
COMPONENTS IN THEPOWER SUPPLY.
NO
IS AUDIO PRESENT ON 1026,PINS 5 AND 6 ON THE SSM
PANEL?
YES
SSB PANELNO
IS PIN 5 OF 7402 <35 VOLTS DC?
YES
IS THE SOUND ENABLELINE APPROX 5 VOLTS
DC?
NO
CHECK 7405 AND 7410. YES
SSB PANEL NO
IS AUDIO PRESENT ONPINS 4 AND 2 OF 7402?YES
REPLACE 7402.NO
CHECK SPEAKERS.YESPage 47
HARE ALL THREE
COLOURS OUT OFCONVERGENCE?
IS +32 VOLTS DCPRESENT ON PIN 7 OF
1017 ON THE SSMPANEL?
YES IS -32 VOLTS DC PRESENTON PIN 3 OF 1017 ON THE
SSM PANEL?
YES
CHECK THE POWERSUPPLY ON THE LSP.
NONO
ARE THE FUSES 1911AND 1912 ON THE SSM
PANEL OK?
YES
CHECK 7012 AND 7014AND CHANGE FUSES.
NO
IS DRIVE PRESENT ON PINS 10AND 1 OF 7009, 7011, AND 7010
ON THE SSM PANEL?
YES
CHECK OUTPUTS 7012 AND7014.
YES
IS DATA AND CLOCKPRESENT ON PINS 6 AND 4OF 7009, 7011, AND 7010?
NO
IS 5 VOLTS DCPRESENT ON PIN 2
OF 7003?
NO
7003 OR RELATED
COMPONENTS.
YES
CHECK 6010, 5 VOLTREGULATOR.
NO
IS 5 VOLTS DCPRESENT ON PIN 2
OF 7009?
YES
CHECK FUSES 1920AND 6009.
NO
CHECK 7009, 7011,AND 7010.
YES
IS REDCONVERGENCE
OK?
NO
DOES THE REDCONVERGENCE
POINTS ADJUST?
NOLOAD DEFAULTS AND
ADJUSTCONVERGENCE.
YES
IS DATA AND CLOCKPRESENT ON PINS 72 AND 78
OF 7003
NO
CHECK 7003 ANDRELATED
COMPONENTS.NO
IS SIGNAL PRESENT ON PINS10 AND 1 OF 7009?
YES
7009
NO
IS DRIVE PRESENT ONPINS 9 AND 11 OF 7012?YES
7012
NO
CHECKCONVERGENCE YOKEAND CONNECTIONS.
YES
IS GREENCONVERGENCE
OK?
YES
IYES
DOES THE GREENCONVERGENCE POINTS
ADJUST?
NO
LOAD DEFAULTS ANDADJUST
CONVERGENCE.
YES
IS DATA ANDCLOCK PRESENT
ON PINS 70 AND 80OF 7003?
NO
7003 NO
IS SIGNAL PRESENTON PINS 10 AND 1 OF
7011?
YES7011
NO
J
YES
Page 48
IIS BLUE
CONVERGENCEOK?
PERFORM A CONVERGENCEALIGNMENT ACCORDING TO THEINSTRUCTIONS IN THE SERVICE
MANUAL.
YES
DOES THE BLUECONVERGENCE POINTS
ADJUST?NO
LOAD DEFAULTS ANDADJUST CONVERGENCE.
YES
IS DATA ANDCLOCK PRESENT
ON PINS 74 AND 76OF 7003?
NO
7003
NO
IS SIGNAL PRESENT ONPINS 10 AND 1 OF 7010?YES IS DRIVE PRESENT
ON PINS 11 AND 18OF 7014?
YES
7010
NO
7014
NO
CHECK BLUECONVERGENCE YOKE
AND CONNECTIONS YES
J IS DRIVE PRESENTON PIN 18 OF
7012?
7012
NO
IS DRIVE PRESENTON PIN 9 OF 7014?YES
7014
NO
CHECK GREENCOVERGENCE YOKEAND CONNECTIONS.
YES
Page 49
PTV900 DISASSEMBLY
REMOVE REAR COVER
REMOVE CIRCUIT BOARD SCREWS
Page 50
GENTLY LIFT THE PC BOARD BRACKET
CHASSIS IN SERVICE POSITION
Page 51
PTV900 Series Convergence Alignment
The set should be warmed up for at least 20 minutes prior to making any Geometry orConvergence adjustments.
A signal must be applied to the set while performing Convergence or Geometry alignments.This is necessary to provide the correct horizontal and vertical sync to the Convergencepanel. Failure to do so will result in an out of convergence picture when signal is applied tothe set.
The Serviced Technician should sit at least 5 to 10 feet from the front of the screen whiledoing Convergence. Ensure that you are eye level with the area of the screen you areadjusting.
When performing Digital Convergence, the adjustments are interactive. A change in onequadrant will affect adjacent areas of the screen. Several passes through the Convergencesequence may be necessary. When doing Convergence, it is advised to follow the sequencepattern when going from on adjustment location to another. Pressing the Right Cursor keywill sequence the Icon through a preloaded sequence.
When the Convergence error is small, a touch up Convergence will be all that is necessary.Do not adjust Green Geometry while in this mode. A compete in-depth Convergence isrequired when the Small Signal Module (SSM) or the Convergence Memory IC, has beenreplaced. If the SSB (Small Signal Board) or the Large Signal Board (LSB) has beenreplaced, a complete in-depth Geometry should be completed before Convergence isadjusted. The Geometry alignment should not be necessary if the SSB or LSB have notbeen changed.
When performing a complete in-depth Convergence alignment, a Screen Template isnecessary to obtain the correct Geometry. The correct Templates are listed below:
43 INCH ST416850 INCH ST416955 INCH ST417060 INCH ST417164 INCH ST4172
Page 52
Touch-up Convergence adjustments
Enter the Digital Convergence Mode (DCM) by entering 0-6-2-5-9-7-(Status or Index) on theRemote control. The following menu will appear:
Select an active channel or Aux Input. A signal must be applied to the set when performingconvergence. If any Customer Adjustments need to be made, the Menu button can be usedto toggle between the Customer Menu and DCM. The MPOSD ADJUST is used to centerthe Customer Convergence grid. A highlighted cross will appear along with the Convergencealignment grid. The highlighted cross should be centered onto the center of the Convergencegrid.
To perform a Touch Up Convergence, highlight SELECTION and press the right cursor buttonon the remote. The following menu will appear:
Selections STORE, RESTORE FACTORY, and RESTORE DEFAULT are not shown afterselecting SELECTION. Press the cursor down button on the Remote for these selections toappear. RESTORE FACTORY loads Convergence defaults from the Factory Loaded sectionof the Convergence Memory IC. RESTORE DEFAULT loads Convergence defaults from the
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sets software.
To perform a Touch-up Convergence:
1. Enter the Convergence Mode and select RED TO GREEN or BLUE TO GREEN. Do notselect GREEN (Green Geometry) without placing a Template over the screen. To perform Green Geometry, refer to the Complete in-depth Convergence.
2. Use the Cursor buttons on the Remote to Navigate from one adjustment point to another. Press the Status or Index button on the Remote to select ADJUST. Use the cursor but tons on the Remote to adjust the Red to Green or Blue to Green. Press the Status or Index button again to navigate to the next adjustment location.
3. After Convergence alignments are complete, press the Menu button on the Remote to return to the SELECTION menu.
4. Highlight the STORE selection and press the right cursor key on the Remote to save changes.
5. Use the GREEN TO RED or GREEN TO BLUE selections to perform convergence when the Green CRT has been replaced.
Complete in-depth Convergence
SCREEN CENTERING
1. Make sure a signal is applied to the set.2. Enter the Convergence mode by entering 0-6-2-5-9-7-(Status or Index). Select an active
channel or input. If the Customer settings need to be adjusted, pressing the Menu button will access the Customer menu.
3. Place a Template over the screen.4. Select GREEN in the SELECTION menu.5. Place a jumper across connector 1005 on the SSM to defeat convergence drive.6. Using the centering rings on the Green CRT, center the convergence pattern onto the
center point of the Convergence Template.7. Press the Menu button on the Remote to return to the SELECTION menu. 8. Select RED TO GREEN in the menu.9. Center the Red pattern onto the Green pattern. 10. Select BLUE TO GREEN in the SELECTION menu.11. Center the Blue pattern onto the Green pattern.12. Remove the Jumper on connector 1005.
Note: If a CRT has been replaced, it is only necessary to perform Screen Centering for the CRT being replaced.
GREEN GEOMETRY
1. Make sure a signal is applied to the set.2. Enter the Convergence mode by entering 0-6-2-5-9-7-(Status or Index). Use the Menu
button to toggle between DCM and Customer Mode. Select an active channel or input
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while in the Customer Mode.3. Place a Template over the Screen.4. Select GREEN in the SELECTION menu.5. The Icon will appear in the center of the screen. Press the Right Cursor key on the
remote to move the Icon to the next adjustment location. At each location press the Status or Index button to enter the ADJUST mode. Using the Cursor keys, adjust the Icon onto the adjustment point on the template. It is recommended that the two outside vertical lines not be adjusted in the first two passes.
6. Continue to follow the pattern and make corrections until the Convergence Crosshatch pattern matches the Template.
7. Press the Menu button to return to the SELECTION menu.8. Use the Cursor down key to highlight the STORE selection.9. Press the Right cursor key to save the alignments.10. Remove the Template.
RED CONVERGENCE
1. Select RED TO GREEN in the SELECTION menu.2. Adjust the Red crosshatch pattern onto the green pattern in the same manner that Green
was adjusted to the Template.3. Save the alignments.
BLUE CONVERGENCE
1. Select BLUE TO GREEN in the SELECTION menu.2. Adjust the Blue crosshatch pattern onto the green pattern in the same manner that Green
was adjusted to the Template.3. Save the alignments.
Complete in-depth Geometry
To activate the Service Alignment Mode, enter 0-6-2-5-9-6-(Status or Index) using theRemote Control. Press Status or Index toggle to the Customer menu. Select an active chan-nel. Pressing the Status or Index button will bring up the SAM mode.
1. Apply a Crosshatch pattern to the set and select that input.2 . Defeat Convergence by shorting the two pins of connector 1005 on the SSM.3. Press the Cursor-down key on the remote and select Geometry with the Right cursor key.4. Adjust the Screen Geometry as necessary.
The following are default values:
VER.AMPL 30VER.SLOPE 34SERV.BLK OFFHOR.SHIFT 32
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HOR.BOW 20HOR.PARALLEL 31EW.WIDTH 22EW.PARA 21EW.TRAP 19EW.UCORN 6EW.LCORN 0H60.WIDTH 2H60.PARA 0H60.SHIFT 7V60.AMPL 0VER.SCOR 18VER.SHIFT 35VER.ZOOM 32VER.SCROLL 32
To save changes, use the Menu button on the Remote to back out to the main menu. Thenturn the set Off using the power button on the Remote or the front of the set. This will saveany changes made.
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REVISED 9/24/01 MM
