Rockford Fosgate power 800a2

I have a Rockford power 800a2 thatnis giving me a weird problem and repair a lot of these but this one is truly unique but I’m sure some will have a great idea of what to check.

Both channels were rebuilt and powersupply, new powersupply caps, new rcas, and new gains.

One channel required R364 (2R7) resistor replaced. The amp worked fine I benched tested it for 30 minutes under audio load bridged at 2ohm.

when I stopped playing audio and remove the speaker wires after about 5 or 10 minutes left channel had 6vdc on out slowly rising to 10vdc and right channel no dc voltage. If I just leave the rcas in and remove them the 2R7 resistor on right channels burns open. Initially during rebuild I replaced D3 also. Any ideas what could cause this scenario?
 

Attachments

  • image.jpg
    image.jpg
    633.4 KB · Views: 114
  • image.jpg
    image.jpg
    511.7 KB · Views: 90
  • image.jpg
    image.jpg
    769.9 KB · Views: 96
Hey Perry,

I replaced the 2.7ohm and caps in series and dc voltage slowly climbs, I don’t see the voltage on the preamp, I’m thinking I may have damaged the irf640 because I had to tin the bottoms, I ordered a whole new batch of irf640pbf fets. To install