Can anyone tell me if these transistor looks burnt?
- Thread starter PooPoo
- Start date
petehall347
the brandy coffee man
unless a transistor is blown apart you need to test properly with a meter .
what are the symptoms ?
what are the symptoms ?
restorer-john
Addicted Member
It's just the anodising on the heatsink. It fades, goes purple and eventually goes a yucky silver down the track. Nothing to worry about.
I LIKE MUSIC
Super Member
The highlighted yellow part is the transistor. The rest, indicated by the red marks is just the metal heat sink. It helps keep the transistor cool.
Its color is not an indication of whether or not the transistor is good.
The circuit board area under and around the transistor is not discolored as it would be if the transistor had been operated at high temperatures.
The transistor may be good or bad. It cannot be judged by the heat sink color.
Below is a picture of the transistor without the heat sink.
You need to use a DMM or one of the component device testers to the test the transistor.
Its color is not an indication of whether or not the transistor is good.
The circuit board area under and around the transistor is not discolored as it would be if the transistor had been operated at high temperatures.
The transistor may be good or bad. It cannot be judged by the heat sink color.
Below is a picture of the transistor without the heat sink.
You need to use a DMM or one of the component device testers to the test the transistor.
PooPoo
Active Member
Ahhh I see now thanks, will test it when I get home and let you know.
I'd be testing the output transistors as well .
gslikker
Super Member
A hard failed transistor will be open or shorted and not dissipating that much.
So, the transistor getting very hot is probably still working (more or less). Other ones being shorted or open will make it run hot.
About the heatsink although it looks just different color to me, does not exclude you from being right, at all.
It could have been discolored heated up a few hundred degrees anyway.
It is the "pitfall" of assuming.....
At least, do not expect the problem to be solved by replacing that one transistor only.
So, the transistor getting very hot is probably still working (more or less). Other ones being shorted or open will make it run hot.
About the heatsink although it looks just different color to me, does not exclude you from being right, at all.
It could have been discolored heated up a few hundred degrees anyway.
It is the "pitfall" of assuming.....
At least, do not expect the problem to be solved by replacing that one transistor only.
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