Author Topic: Sunn Solos II - Turns on though no sound  (Read 629 times)

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Offline Babyshins

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Sunn Solos II - Turns on though no sound
« on: May 30, 2024, 08:33:40 pm »
Hello all

I have acquired a Sunn Solos II that turns out but sends out no output through any of its jacks. I've tried the preamp output as well as the power amp input and there is nothing. I haven't been able to find much material online on repairing solid state amps, and would love to be able to do this type of repairs myself. Do you all have any resources or advice you could point me towards to help teach me how to bring this beauty back to life?

Thanks  :-D

Offline loudthud

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Re: Sunn Solos II - Turns on though no sound
« Reply #1 on: June 05, 2024, 01:44:47 am »
There are schematics and layout diagrams in this thread:

https://forum.sunnstillshines.online/index.php?topic=4781.msg18696#msg18696

It looks similar to the Concert series amps. You can check Voltages on the schematic but beware, there is a floating power supply in the power amp. Check for DC at the speaker output, that's usually an issue with the output transistors or a short in the Driver Transformer.