Hi there!
EDIT: Forgot to mention that the +5V rail is fine as well at around 5.2V
I have a BSS FDS-336 audio DSP that was hooked up to a power generator with unclean power. The generators voltage would fluctuate down between 206-260VAC all the time. This must've damaged something in the power supply section because now the DSP occasionally displays "power failure" on screen, which in turn means the DSP doesn't turn on the output relays.
The DSP has an Switch mode psu with multiple voltage rails on the secondary side. -18V, +18V, +8V and +5V
The 2 rails that seem to be affected/damaged are the +18V and -18V rails, from which +15V and - 15V are made using a TIP32A and a TIP31A.
The -18V rail is around -14.2V
The +18V rail is around 13.5V
now the weird thing is that the +8V rail is just fine, while it's on the same transformer secondary, so it can't be a issue with the PWM controller chip or something similar.
I've tried multiple things to fix this issue, a new PWM chip (just in case), A new switching MosFET, I tried replacing the rectification diodes on the secondary side with some 1n5408's I had laying around, but those got incredably hot and started smoking.
I've also attached the schematic for the PSU to clear things up a little bit more
The voltage rails on the secondary side are, from top to bottom:
+15V
+8V
-15V
+5V
EDIT: Forgot to mention that the +5V rail is fine as well at around 5.2V
I have a BSS FDS-336 audio DSP that was hooked up to a power generator with unclean power. The generators voltage would fluctuate down between 206-260VAC all the time. This must've damaged something in the power supply section because now the DSP occasionally displays "power failure" on screen, which in turn means the DSP doesn't turn on the output relays.
The DSP has an Switch mode psu with multiple voltage rails on the secondary side. -18V, +18V, +8V and +5V
The 2 rails that seem to be affected/damaged are the +18V and -18V rails, from which +15V and - 15V are made using a TIP32A and a TIP31A.
The -18V rail is around -14.2V
The +18V rail is around 13.5V
now the weird thing is that the +8V rail is just fine, while it's on the same transformer secondary, so it can't be a issue with the PWM controller chip or something similar.
I've tried multiple things to fix this issue, a new PWM chip (just in case), A new switching MosFET, I tried replacing the rectification diodes on the secondary side with some 1n5408's I had laying around, but those got incredably hot and started smoking.
I've also attached the schematic for the PSU to clear things up a little bit more
The voltage rails on the secondary side are, from top to bottom:
+15V
+8V
-15V
+5V
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