Need help with Event PS8 powered studio monitor repair.

Thread Starter

nbtone

Joined Oct 14, 2016
65
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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Thread Starter

nbtone

Joined Oct 14, 2016
65
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
 
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