Are These Circuit Traces Bad

[DaveWM]

diode check base to collector check it like a diode
diode check base to emitter check it like a diode
Ohm check emitter to collector should read open both ways (switch leads).

if if doubt just do a you tube search on checking transistors with DVM there are plenty of demos.

I use a analog meter that has a built in reversing switch in the resistance mode.

[TinCanAlley]

Originally Posted by DaveWM

diode check base to collector check it like a diode
diode check base to emitter check it like a diode
Ohm check emitter to collector should read open both ways (switch leads).

if if doubt just do a you tube search on checking transistors with DVM there are plenty of demos.

I use a analog meter that has a built in reversing switch in the resistance mode.

Got it. So now I must wonder why the transistor I replaced on the NOS horizontal board doesn't work in the board, but checks out good when tested. I've gone back and forth with it a few times in the board and it sure doesn't work. The transistor from the old horizontal board works perfectly.

I know I'll get it. I've made quite a bit of progress and gained quite a bit of knowledge in the past month.

Thanks

[DaveWM]

Originally Posted by TinCanAlley

Got it. So now I must wonder why the transistor I replaced on the NOS horizontal board doesn't work in the board, but checks out good when tested. I've gone back and forth with it a few times in the board and it sure doesn't work. The transistor from the old horizontal board works perfectly.

I know I'll get it. I've made quite a bit of progress and gained quite a bit of knowledge in the past month.

Thanks

IF a transistor works in one board and not in the other in the same location, I would say the transistor is ok, I am a little confused on this, make sure you are testing correctly reverse the E to C leads, should read open both ways

BC open one way, low resistance when leads reversed.
BE open one way, low resistance when leads reversed.

you need to make sure you are doing this right. But I dont really understand why you are futzing around with the horz board. Check the diode in the blanking circuit.

[TinCanAlley]

Originally Posted by DaveWM

IF a transistor works in one board and not in the other in the same location, I would say the transistor is ok, I am a little confused on this, make sure you are testing correctly reverse the E to C leads, should read open both ways

BC open one way, low resistance when leads reversed.
BE open one way, low resistance when leads reversed.

you need to make sure you are doing this right. But I dont really understand why you are futzing around with the horz board. Check the diode in the blanking circuit.

The horizontal board gives me a known bad circuit that I can comfortable work with for practice.

The transistor from the NOS board is the exact same NPN as on the original board. I put the meter in diode mode and connected the positive to the base (the E, B and C are clearly marked on the metal tab). I connected the negative lead to the collector and got a reading. I then connected the negative to the Emitter and got a reading. I then connected the positive to the emitter and the negative to the collector and got nothing. I reversed the leads and got nothing.

I put that transistor back on the board, install the board and the TV won't fire up other than sound. If I take the transistor from the old board and put it in the new board, it works like a charm.

I guess I'll just let this one go. Since I seem to be doing it correctly, maybe there's something else wrong Maybe the sockets don't like the legs of this one (they are gold plated unlike the older, working one). Maybe it has a thing about flashy transistors.

Anyway, I'll just wait for the scope and my brother.

[DaveWM]

Originally Posted by TinCanAlley

The horizontal board gives me a known bad circuit that I can comfortable work with for practice.

The transistor from the NOS board is the exact same NPN as on the original board. I put the meter in diode mode and connected the positive to the base (the E, B and C are clearly marked on the metal tab). I connected the negative lead to the collector and got a reading. I then connected the negative to the Emitter and got a reading. I then connected the positive to the emitter and the negative to the collector and got nothing. I reversed the leads and got nothing.

I put that transistor back on the board, install the board and the TV won't fire up other than sound. If I take the transistor from the old board and put it in the new board, it works like a charm.

I guess I'll just let this one go. Since I seem to be doing it correctly, maybe there's something else wrong Maybe the sockets don't like the legs of this one (they are gold plated unlike the older, working one). Maybe it has a thing about flashy transistors.

Anyway, I'll just wait for the scope and my brother.

in the diode mode did you reverse the polarity after the Base to Emitter same for reverse the Base to collector? diode checks must be made both ways same on transistor, you must check base to emitter and base to collector BOTH ways.

[TinCanAlley]

Originally Posted by DaveWM

in the diode mode did you reverse the polarity after the Base to Emitter same for reverse the Base to collector? diode checks must be made both ways same on transistor, you must check base to emitter and base to collector BOTH ways.

Yes, I did the following:

Positive on base and negative on emitter and collector (readings on both)
Negative on base and positive on emitter and collector (no readings)
Negative on collector and positive on emitter (no readings)
Positive on collector and negative on emitter (no readings)

Those are all the possible combinations. Like I said, I have no idea why this one won't work, but I am confident I've tested it properly. Oh well, like I said. Maybe it's something about the socket.

[DaveWM]

those should be about .6v for a silicon transistor (when you got the reading).