22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 1

TECHNICAL DIAGNOSISAND

TEST EQUIPMENTS

INTRODUCTIONBefore starting doing troubleshooting, some step should be alert such as;

Type of equipment to repair? The symptom? Circuit Diagram? Technique could be used ?

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 3

TECHNICAL DIAGNOSIS

SYMPTOMTRACING

TECHNIQUE & THE INJUCTION

VOLTAGE MEASUREMENT

RESISTANCE MEASUREMENT

PHYSICAL TECHNIQUE

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 4

SYMPTOM

Equipment Symptom

1 Colour TV No colour & no sound

2 Radio Stereo sound

3 Osilloscop Display

4 Audio Gen. The output

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 5

As a guideline for determining the damage, connection orcomponent.

Basic knowledge about the operation and function of the device. Forthe examples:

TRACING TECHNIQUE & THE INJUCTION

If the audio is not heard, we can guess which part is damaged or the place where we need to check first. Here we can say that the speaker or amplifier power or tone controls or control materials (volume control) problem.

If the circuit schematic does not exist, create a trace on the circuit, identify the code number of components and joints. This will speed up the process of a circuit trace or detect damage to components.

Once identified, the PART and the type of circuit damage, identify the techniques that we have to do. They are experienced, simple techniques that examine the schematic circuit and continues to launder.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 6

TRACING TECHNIQUE

The step will be : Input and output VCC and grounding Value of component

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 7

Tracing technique normally start from the inputpart. If still having to find, tracing can be startfrom the output part.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 8

Tracing Technique For Printed Circuit

Vertical Deflection circuit TVWe can find the wire that is connected to a coil ofdeflection yoke TV as a reference in the output, thentrace to the circuit until the next amplifier.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 9

PCB Feedback Amplifier

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 10

Tracing technique are suitable to used forsimple circuit such as audio amp, pre-amp,tone circuit or etc.

Feedback Amplifier circuit.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 11

Technique Injuction Signal

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 12

Block diagram of an Output Detector

Flow chart to check functional of the speaker are;

1. Use ohm meter or signal generator

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 13

2. If the speaker ok, injection signal can beused at the power amplifier (output driver).

3. If normal, move the probe to the input audiogenerator that drives before or after C3. Look atthe output.

4. If the signal is normal, we can continue to check the tone at the input circuit. This circuit consists of a filter circuit. Output may drop if there is a slight change of tone adjustment. If this circuit is a low or damaged products can not be adjusted tone.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 14

5. If normal. Do the injection technique at the input can be continue

The level at signal generator need to decrease to get an output without distortion. In a normal situation the output can get a maximum.

Do a test point before and after capacitance C5.

While doing centralize the control be careful with the injection not effected to the signal.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 15

Determine the parts of the amplifier

Determine supply voltage and supply the correct values to the circuit

Determine the generator output at the appropriate level and frequency of 1kHz or

400 Hz

Check on the output of the start of the speakers (if any) or use the scope as the detector output

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 16

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 17

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 18

VOLTAGE MEASUREMENT To measure voltages, the meter must be connected

ACROSS things; across resistors, across the battery etc. When measuring DC, connect the red meter lead to the

most positive point, and the black one to the most negative. When measuring AC voltages it doesn't matter which way the leads are connected.

It's best to select a high voltage range on the meter before connecting it and then switching to a lower range if necessary. This protects the meter, especially moving coil ones, from being damaged by having too high a voltage applied to them.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 19

HOW TO MEASURE VOLTAGE

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 20

RESISTANCE

When measuring the resistance of the circuit and determine there is no low resistance, inductance and transformers in the relevant connections.To determine the resistance of the open, make sure the stated value means resistance to change is open or high value.Size at least twice to rotate the polarity.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 21

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 22

When measuring resistance the power to the circuit must be SWITCHED OFF. Ensure that there are no components in parallel with the component to be measured. There is no need to observe the polarity of the leads.

DIODE

Forward and Reverse Bias. If found to be reading as usual diode

(outside the circuit), the diode can be considered in good condition.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 23

HOW TO MEASURE DIODE

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 24

TRANSISTOR

NPN type or PNP type Power transistors, the input is fed by a

transformer in the base runway, like the horizontal output (TV), switching type power supply circuit (switching power supply).TR501 resistance measurement, the resistance between the base and emitter resistance is low. Provisions may be made by simply measuring the resistance between the collector and base only.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 25

HOW TO MEASURE TRANSISTOR

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 26

PHYSICAL TECHNIQUE

Eyes, by watching hear, Smell and Touching.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 27

Eye

Effects by observing the component or printed circuit board, burnt, loose, broken, and so forth.

Examplesfuse failureeffects of smoke, 'sparkling' orburned.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 28

SMELL & HEAR

components of the burn or 'sparkling' can not be seen with the naked eye, but it sounds or smell.For example;often there is a high voltage transformer sparkling if insulating cracks but can not be seen just hear a 'hiss' ortransformer that overheated just smells burnt.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 29

TOUCHING

effects of taste components overheating, but the detection is made must take into account security.For example, the components close to high voltage, ac voltage supply, large capacitor values of charged and so forth.the sense to know whether the broken parts, loose solder, torn, broken, etc.

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 30

Q &A SESSION

22/01/2011disediakan

oleh Rodzah Binti Hj Yahya 31

22/01/2011 disediakan oleh Rodzah Binti Hj Yahya 32