How do I test a transistor???

qbass187

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Hey guys,
I'm trying to find out if it's one of the transistors in the Vertical output section of my MatsuSHITa TM-202G

How do I test it?

That perticular transistor (Type- 2SC1683LB) appears to obsolete; so if I need to replace it does anyone know the proper replacement? How I can figure it out?


Thanks again, ERIC
 
NTE375 is the cross reference for that part. Should be pretty easy to find.

For transistors, if you don't have a tester (like a super cricket, etc) you can measure the ohms between the legs. Place the black lead on the base, and measure red on collector and emitter. Then place red on the base and measure black on collector and emitter. One way should deflect, and the other shouldn't.

If you have really, really low ohms between the collector and emitter, it is likely shorted.


EDIT - er sorry, I was just talking about deflection between the legs, which you should get. The resistance was supposed to say 'between the collector and the emitter' not two legs.
 
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NTE375 is the cross reference for that part. Should be pretty easy to find.

For transistors, if you don't have a tester (like a super cricket, etc) you can measure the ohms between the legs. Place the black lead on the base, and measure red on collector and emitter. Then place red on the base and measure black on collector and emitter. One way should deflect, and the other shouldn't.

If you have really, really low ohms between two legs, it is likely shorted.

I believe you are confused my friend. Resistance (ohms) will not tell you jack shit about a transistor. Diode test on the other hand is a different story.

NTE375's are very easy to find, and Bob is pretty cheap on them.

.
 
The rule of thumb when testing transistors is "test resistance both ways between all the combinations of legs."

Collector-Base
Collector-Emitter
Base-Emitter

BUT... this can't always be done in circuit as some other parts could offer a lower resistance path such as drive transformers and flyback transformers in the horizontal circuits. Also, damper diodes are integrated into some horizontal output transistors. These are high speed diodes and the device will show low resistance both ways.

The trick is that those high speed diodes will still have *some* resistance where shorted devices usually are below 1 ohms.
 
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