Need help with Event PS8 powered studio monitor repair.

Thread Starter

nbtone

Joined Oct 14, 2016
64
I’ve attached the schematic. One of the 22uf capacitors connected to either U1 or U2 was blackened, and I replaced it. Now the indicator light works, but I still have no sound. I’m wondering if I should replace the chip, but I’d like some expert help with diagnosing.
 

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anniel747

Joined Oct 18, 2020
421
I’ve attached the schematic. One of the 22uf capacitors connected to either U1 or U2 was blackened, and I replaced it. Now the indicator light works, but I still have no sound. I’m wondering if I should replace the chip, but I’d like some expert help with diagnosing.
Chip?
 

Thread Starter

nbtone

Joined Oct 14, 2016
64
At the bridge rectifier there is +24 vdc on one side and -35vdc on the other.
At U1 pin 1 has -.9v pin 4 has -35v pin 5 has -.9v pin 9 has -.4v and pin 10 has -.9v.
At U2 pin 1 has -.9v pin 4 has -35v pin 5 has -.9 v pin 9 has -1.5v pin 10 has -1v
At U3 pin 4 has -15v pin 7 has -.8v
At U4 -15v. -1v
At U5 -15v. -1.9v
 

anniel747

Joined Oct 18, 2020
421
At the bridge rectifier there is +24 vdc on one side and -35vdc on the other.
At U1 pin 1 has -.9v pin 4 has -35v pin 5 has -.9v pin 9 has -.4v and pin 10 has -.9v.
At U2 pin 1 has -.9v pin 4 has -35v pin 5 has -.9 v pin 9 has -1.5v pin 10 has -1v
At U3 pin 4 has -15v pin 7 has -.8v
At U4 -15v. -1v
At U5 -15v. -1.9v
You have a shorted positive rail.
 
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