Sunfire subwoofer repair

[sealand1]

Hi,
I'm looking for a repair service for sunfire eq10, looks like all experts have retired, thanks.

 

[wolf_teeth]

You should search this forum for the info of others making the attempt. IIRC, it's not worth it. Pull the driver and PR, and use them with another amp.

 

[sealand1]

After replaced some big caps on power board, it works. But when volume is up, it makes rattling noise.

 

[sealand1]

I assume some caps on preamp board also expired, need to be replaced.

 

[sealand1]

Found the dc output from speaker terminal, when volume is up, the dc voltage is going to higher, this is the reason why driver is rattling when input signal is strong.
Also measured the preamp output from exc_limit terminal, it also has strong dc offset, so the first thing is to troubleshoot why preamp has dc output.

 

[sealand1]

The full schematic can be found from here,
https://thecarversite.com/manuals/Sunfiremandir/Sunfire Schematic Subwoofer TS-EQ.pdf

I very appreciate if anyone can give me some advice, thanks.