Anyone do anykind of home electronic/appliance repair?

[makenzie71]

I'm a noob when it comes to home audio crap...I've got two problems with some stereos:

First one has 5 channels...left/right tweets, left/right mids, and a subwoofer.  One evening it started blowing it's low/mid fuses.  I replaced with one step higher a fuse to try and identify the problem area and this wierd little rectafier looking thing started smoking.  It's a long black ceramic piece with 15 long pins all down one side all soldered to the primary circuit board, mounted to a steel bracket and it is bolted to the stereo's central heat-sink.  I just need to replace it but I don't know what they're called.  I can post a pic later tonight if I need to but this is something I'm seeing in almost every amp I've looked in...which I would have just pulled one out of my other amps but none of them have enough pins.  Anyone know what this little device might be called so I can find one?

Second, I have a 5 year old Sony 60-cd changer that I LOVE...best shelf system I've ever had (game-sync = total pimp).  I had this thing wired up with the two shelf speakers that came with it and two 8" subs.  This stressed it but most times it ran everything without any problem at all.  One day I turned my TV off before shutting the stereo down first...all the speakers thumped HARD and since then it produces no sound.  Everything else works great.  Any ideas where I would look on this one?  I've torn it down and inspected all of the fuses .  I've tried inspecting all of the diodes and resistors and what not but there's about 4000 of them all together (not kidding) and all seem to be going fine.

Advice is spiffy.  No repair shops within 200 miles of me...

[trumpetguy]

The multi-pin device is an IC amplifier.  Some are driver stage amps, or, in low powered  amps like 25W, it might be the main amp.  It will be amp-specific (there are many varieties).  You can get the number off of it and replace it, BUT if you didn't cure the original problem, you'll just fry the new one too.  Sounds like there was a short somewhere, blowing the fuse.  You put in a larger fuse (not a good idea) and allowed it to fry a component (the IC amp) instead of the fuse.  That's one I'd simply replace the whole amp (if not too expensive) or take it to the shop.  With labor and troubleshooting costs, buying a new one may be the cheaper option.

As for the other issue, find a way to test the components in the chain individually (speakers, then amp, then CD-changer, etc.).  Hopefully you can isolate the problem component.

[makenzie71]

thanks...knowing what the piece is called I already found a replacement lol.  This system is a lot simpler than the sony...all the components are layed out nicely.  This is the only thing in between the fuses and the speaker jacks that had a problem.

As for the sony...I've been attempting to trace back from the speakers but like I said...it's complex and I just thought I'd see if there might be a specific component prone to failure with brief power surges (like cutting the signal before shutting down)...

[starwalt]

+ 1 to the previous comments. The IC was your stereo drive amp all nicely bundled in a modular package. There are several online component suppliers that may sell single items. The systems with the big amps just use the IC type to drive larger FET amps.

Regarding the Sony, if you have a DVM check some of the power supplies to make sure that hasn't failed. That "thump" was a  current spike that the power components may have been able to handle, but the power supply couldn't hang with.  That's the problem with asymptotic current spikes. Infinite load is just too much for some parts. 

[makenzie71]

The main power supply coming in to the stereo is fine...in fact everything else on the stereo works perfectly.  It's just the speakers...I'm not sure how to test power coming to the speakers yet...this is a learning process.

I fixed the RCA...the original problem was a rectifier that I couldn't see without completely disassembling the bastard.  Got it fixed, replaced the IC (radioshack hooked me up) and it works like new.

[makenzie71]

hey anyone know anything about powered subs?  I'm trying to find something to provide a bit more punch and I'm having a hard time getting my car stuff to work with my house stuff (something about that whole 4/6/8 ohm thing).

[NiceGuysFinishLast]

are you running from the sub pre-out on the receiver to an amplifier to the car sub, or what?

[makenzie71]

There's a seperated sub for the stereo but I'm not running off that...it draws too much power for some reason.  I'm trying to run off the high freq channels to a low-pass filter, then to the amp, then to the sub.  Mostly it's been acting like I'm overpowering the sub (and sounds like shaZam!) and there's only a 50w amp on it...I used to run it with a 200w amp and it sound great.