procrastineer

Have a look at documentation done by Dale Thompson: http://www.thompdale.com/bash_amplifier/5-1/5-1_bash_amp.htm

Sounds like issue with the BASH amplifier chip. If you are comfortable with electronics you could have a look yourself or get in touch with one of several people who repair klipsch amps like elite-tronics (?)

Yes , the previous owner did say some work was done under warranty. I have removed the daughter board. When I was testing for continuity to make sure that the daughter board PCB inserts (8 pin connector) are not conducting due excess to solder from de-soldering, and I realized the PCB insert 6 and 7 is conducting. Could this be due to faulty Q2 (IRF 740)? Also PCB insert 1 and 4 is conducting for some reason? Only way I can see this happen is due to transformer tap 6 and 7 shorting. Thanks for your help.

Thanks, I figured out that the resistor combination that I mentioned in the first post varies depending on the 120V (US) and 230V (rest of the world?) mains supply. How do you know that someone worked on the daughter board? I'm guessing from the different color of the board? I am considering replacing the susceptible components in the daughterboard but it looks like I have to unsolder the daughter board first as it is really close to the transformer on the AC-DC converter board. This is rather difficult since daughter board has eight pins.

Hey everyone. I bought a “as is” Klipsch Promedia 5.1 speaker system from an auction site. Before opening the back of the sub I tried turning it on few times and twice I heard a loud “thump”, most times it didn’t turn on at all. I used to have a Logitech z680 and have heard similar noise from sub when turning it on. As many have pointed out I found documentation done by Dale Thompson at http://www.thompdale.com/bash_amplif...1_bash_amp.htm very useful. With above documentation I verified that the Line filter is working fine by measuring 240V AC from T1 and T2 terminal of the Line Filter board. The problem seems to be in the AC-DC converter board. It seems the R519 and R520 resistors on AC-DC board have become open circuits (checked with continuity checker on the multimeter). According to the schematics these two resistors should be "zero ohm" interconnecting links. As you can see from the photo [http://imgur.com/KwW4l.jpg] only one resistor still in place is the R521 resistor. Can someone with a working sub check that there is a connection on R520 and R519? Thanks for any help.