stpete cooling

Infinity used the same chip on some of their powered home speakers (IL60 may have been the model of one of them). I bought a couple of these chips from an Infinity repair shop early last year. Infinity used the same part number. Cost with shipping can get over $20 each.

When I tried the tech department some months ago, I found out Klipsch (understandably) will not share schematics on amps that are currently being sold. They were very helpful with some other schematics in the past! Klipsch recently extended their repair service to include the sub-10, for $60 shipped. That is far better than buying a new amp panel for over $160.

Take a look at a recent post (5-30-07) noting the repair to the controller was not the pot, but an IC, easily found on ebay.

Excellent advice! I look forward to trying that fix. I just found a seller on Ebay (honestcard) where these chips are $.29 each and $3 shipping in any quantity (ordered 3 chips for $3.87). I was stumped, because the control potentiometers are sealed (hard to clean), showed a smooth sweep, yet I had that irritating popping, too.

FR104 stands for a fast recovery 1 amp diode. I sometimes have used a FR304 (3 amp), but that should not be necessary if you take other steps to reduce the heat build up in that area. Power handling of semiconductors decreases rapidly (not linearly) as ambient heat rises.

R527 is a 4.7 ohm resistor. The heat may have discolored your resistor to look like a black band, but as I recall it is actually gold when new, a multiplier of .1, rather than 1. Try a 4.7 ohm, or even a 5 ohm 5-watt resistor. But also check the diode next to it, it can get leaky after being exposed to heat for a long time.

I have fixed a few of these amps. They have a constantly on power supply section that gets hot, eventually to the point of charring the board. After doing the repair, I add a cooling fan (I will be selling a KSW10 on ebay soon) to remove that hot spot. There is a good chance I can repair the panel, if you wish. It could be a zener diode, or even the safety thermal fuse wrapped inside the power transformer.

I'd be interested in taking a look at someone's broken amp. I've had success repairing some KSW-10 amps, and by adding a quiet cooling fan on the interior side of the panel and a pair of heat sinks to some regulators that overheated the board, have solved the heat problem for the future.

A few of these damaged Sub-10 subs have been auctioned on ebay recently with that exact problem. Klipsch does not offer a repair service, and the replacement amp is about $160 as I recall, so be glad you have a warranty. I would guess Klipsch will not even try to diagnose the problem, and just plug in a new board, but if you can ask Klipsch to report to you what particularly failed on your units, please post it for the benefit of future owners and for when the warranty expires.

The IRF 740 is used as part of the switching power supply in the Promedia 5.1 systems. I am not familiar yet with the 4.1, but I see a familiar miniboard in the photo; Indigo's BASH design uses it to quickly adjust (via an IRF 740) the supply voltage to the amplifiers based on the load.