Sparks and a volatilized transistor
- Thread starter Sergimm
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- kaboom shorted transistor
Sergimm
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Ok I got -34.07V on F803 and 33.76 on F804. Opposite signs of your numbers...
Sergimm
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Let me know if these are clear enough.
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Typo in the shitty HFE service manual scan.
Still getting this ?
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Sergimm
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Yeah still getting it. Using a Raspberry Pi with a HiFi Berry DAC plugged into AUX input. Before that I used the audio jack output of my laptop to make sure, with same results.
Sergimm
Active Member
As I mentioned, the “on” LED doesn’t turn on anymore either, so I went to measure the current just like I did with the fuse and it’s getting 25V, which I think it’s consistent with the schematic (23V).
I have no idea about what’s wrong but it must be related to that transistor short, given that before that incident but after the recapping I could hear music in this amp (albeit it sounded terrible). Are there other telling checks I could try to narrow down the problem?
I have no idea about what’s wrong but it must be related to that transistor short, given that before that incident but after the recapping I could hear music in this amp (albeit it sounded terrible). Are there other telling checks I could try to narrow down the problem?
Check that the two wires going to the LED are still intact.
Sergimm
Active Member
Oh boy, we are back in business! It was the tape switch, so embarrassing. Thank you so much! I am unblocked now
The amp now sounds better than before recapping (before sound was almost impossible to hear), but still terrible. Now the sound comes through, but it is extremely muffled. And I can't properly listen to it unless I turn the volume almost all the way up. Given that I changed all electrolytics, should I assume I should check transistors? What would be the next logical place to look into, in your opinion?
The LED wires seem fine, but the LED is still not lit. it may well be that it chose this very moment to die...
Sergimm
Active Member
For Q801:
E=26.6V
C=38V
B=27.28V
after setting all volume controls of source to max, the volume issue seems to be ok now, but when I go up in volume it sounds quite distorted, especially on the bass. If I stay in lower volume it sounds muffled but doesn’t distort. All tone controls are at 0.
E=26.6V
C=38V
B=27.28V
after setting all volume controls of source to max, the volume issue seems to be ok now, but when I go up in volume it sounds quite distorted, especially on the bass. If I stay in lower volume it sounds muffled but doesn’t distort. All tone controls are at 0.
Sergimm
Active Member
7.27V