Can anyone identify this transistor?

[Spence]

Looking to repair this circuit board that controls my vehicles AC. I've come across this transistor that is BCE and has given me the readings as follows:

B-C=0
B-E=.270
C-E=.270

C is also where I'm not getting any power on and this is the failed part of the circuit and the volts seem low to me but I'm all a noob to this. I'm looking to replace this transistor. If anyone can identify this or recommend something from maybe RadioShack that'd be very helpful. Thanks!

 

[davenn]

Looking to repair this circuit board that controls my vehicles AC. I've come across this transistor that is BCE and has given me the readings as follows:

B-C=0
B-E=.270
C-E=.270

C is also where I'm not getting any power on and this is the failed part of the circuit and the volts seem low to me but I'm all a noob to this. I'm looking to replace this transistor. If anyone can identify this or recommend something from maybe RadioShack that'd be very helpful. Thanks!

Hi Spence
welcome

dunno how you were reading those measurements as they stand that are meaningless till we know if they were voltage or something else and between where and where you were taking the measurements and with or without power applied

You have another serious problem ....
top pic
lower left
there is a circuit track that has fused .... did you see that ? presumably not as you didn't comment

To test to see if the transistor is faulty, it would have to be removed from the circuit
I thought the transistor mite have been a 2SA8651 but I cannot see any info on google, so am now not sure what it is

Dave

 

[Spence]

Thanks Dave! Those readings were taken without power applied. I was going off YouTube videos and how to test NPN transistors so that's what I came up with. Yes, I'm aware of that area. This happened when it was on the car, my fault, but used a copper wire to join the track again. I'll go ahead and remove the transistor from the circuit and give a test again.

 

[Spence]

Got the transistor removed from the board. Going across C and E with positive or negative I get no current flow as I believe is right. However, touching +B to -C I get zeros across the board, touching +B to -E I get a open signal, no zeros or a volt reading.

 

[BobK]

You don't say what kind of reading you are taking. Is this with the diode test range? If so, try the leads the other way as well. A PNP transistor will need the negative lead on the base.

Bob

 

[Spence]

Sorry. Yes this is a diode test. I haven't tried the negative lead on the base yet. Going by how it was printed on the transistor, and board, I was testing it as a NPN. I'll try the other way and see what happens. Thanks.

 

[Spence]

Tried it was definitely NPN. Picked up a TIP31 and tried that, but not getting enough volts through the circuit.

 

[Viktory2k1]

I think your problem is elsewhere. Make and model of car please.

 

[Colin Mitchell]

It maybe a PNP transistor
You need to do my finger test

 

[Arouse1973]

It maybe a PNP transistor
You need to do my finger test

View attachment 19697

Love the pictures. If you do this it is advisable to take ESD precautions so you don't damage the transistor from any ESD events.
Adam

 

[Spence]

I think your problem is elsewhere. Make and model of car please.

You were correct. It was the high pressure switch on my ac compressor. It was shorting out to the body of the compressor. Got it all sorted out. Still had to get a replacement ac control unit. I'll tinker with the old one on another day. Thanks for all the help everyone.

 

[Spence]

It maybe a PNP transistor
You need to do my finger test

View attachment 19697

I'll definitely refer to this when I do any future tests. Thanks.

 

[Viktory2k1]

Even a high pressure switch is rare to go on you unless the compressor was seriously screwed up.
Did you have to buy a whole compressor with clutch?

 

[HellasTechn]

Dear Spence. You need to remove the semiconductor "transistor in your case" in order to obtain a reliable reading with your measurement instrument. In other words just remove it from the PCB and test it alone with a multimeter.

From the base of the transistor it should give you a reading to the emitter and collector and by reversing polarity of your probe it should not .

i think this is the datasheet :

http://documentation.renesas.com/doc/products/transistor/r07ds1065ej0100_pomosfet.pdf