How To Repair A Klipsch Subwoofer

Engle Alighway · March 8, 2022

Howdy ngen33r, I am posting here in your thread to hopefully get some help. I have a RPW-10 that worked great for years and and then no longer was working...I unfortunately left the switch in the "car on" position. I don't use the surround audio system on this TV ofttimes, so i do not know how long ago information technology stopped working...information technology may have been several months ago! I found the fuse was blown, replaced it and it blew immediately. I removed the plate amp, but I did not encounter anything obvious in regards to blown components in the power supply. A Google search brought me to this thread and I was on my mode! I followed every suggestion in this thread: 1) rebuilt PDC, 2) replaced mosfets, three) full epitomize, 4) replaced TH3, and eventually upgrading Q5 to 2N4401 from SOT 23.

Rebuilding the PDC was washed based on your schematic in the kickoff post of this thread. Withal, the values of my original resistors were totally different from those in your schematic---although the board number was exactly the same (660038RA). See pictures beneath:

Original board:

Rebuilt PDC:

I as well replaced the 2 IRF730 Mosfets with two IRF740 Mosfet transistors. I also replaced TH3 (DSP104) even though there was no damage to it and then I replaced all CAPs with Nichon and Kemet (470uf) 105 C caps except I did not change the two 35V 4.seven non-polar caps at C48 and C53 (I ordered regular polar caps by error). In improver to all of the suggestions y'all fabricated in this thread, I also (6) replaced the two voltage regulators at U4 and U5, (7) replaced the transistor at Q8, and for good measure (ix) I inverse out all 5 of the output transistors (IRFZ14). The picture below summarizes all of the changes:

Summary of All changes (before changing out Q5):

Now, I am no longer blowing fuses but the amp is even so not working. After a short period of being on, the Mosfets really start to heat upwards...I am not noticing any other components getting warm and there is absolutely no speaker noise. I am now stuck and I am most tempted to supercede the safety capacitors (yellow thingys) and the bridge rectifier. Still, I wanted to reach out to you first for some guidance. I have no schematic and I haven't got the slightest inkling how to trouble shoot without knowing voltage "test points". Can you please give some advice? I am tempted to throw in the towel and but a new plate amp replacement, but I feel like I am as well far into this to quit now...exercise you lot have any advice for a hobbyist? Thanks in advance!

Edited March 8, 2022 by wderbi