Self healing transistor.

kaplang

kaplang

Works for me !
I have been troubleshooting a Sansui receiver that will only come out of protection mode if the main driver board is disconnected. I have determined that one of the transistors on the left channel side is causing the problem. With the board connected and receiver powered on I sprayed the left channel transistors with some freeze spray to see what would happen. It came out of protection mode and started playing through both channels. Now when I turn it off and on it comes out of protection mode and stays that way. It seems to be OK now. I can’t explain it but it seems like the freeze spray healed the transistor.

Anybody ever experience this?

All the driver board transistors will be replaced.
 
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You've probably disturbed a bad connection, likely within the transistor, to fix it. Rest assured, the problem will come back shortly!
 
kaplang said:
I have been troubleshooting a Sansui receiver that will only come out of protection mode if the main driver board is disconnected. I have determined that one of the transistors on the left channel side is causing the problem. With the board connected and receiver powered on I sprayed the left channel transistors with some freeze spray to see what would happen. It came out of protection mode and started playing through both channels. Now when I turn it off and on it comes out of protection mode and stays that way. It seems to be OK now. I can’t explain it but it seems like the freeze spray healed the transistor.

Anybody ever experience this?

All the driver board transistors will be replaced.
Click to expand...

I've experienced this same, "self healing transistors", but related to the heating done by the soldering Iron. As said, the problem comes back later.

Also I have seen some "self healing ICs", ICs that fixed while measuring with the oscilloscope. Those didn't fail again. Several years ago and still working.
 
Ive had dead ic's come back after heating them.

Ive gotten another 6 months out of a video card by baking it in my toaster oven too.
 
I wouldn't count on that to keep working either.

Also had similar miracles from heating ICs. The odometer on one of my cars uses a cute little 8 pin DIP IC to store the mileage, and its a common problem to have it go stupid and stop reading. The only fix I've ever seen is to re-flow the solder on the chip. I did it and it works, but I suspect the solder wasn't actually the problem. I'll see how long it goes, been a year so far.
 
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