Old stereo amplifier

[Cynic]

I've got an old sony amplifier (model: TA-AX320) that I've got hooked up to a cd player and my computer for listening to music. It has a problem where you'll hear some clicks and crackles and eventually the sound just cuts out, if you leave it for 10-20 minutes it then comes back on. This happens at random times (can be between 5 minutes or 5 hours) and it has started happening more frequently. Also when this happens if you tap it on the top of the unit it will start producing sound again. This is a solid state amp so no tube issues and judging by how old it is (my old man had it before i was even born) it wouldn't be worth the money to get it professionally fixed. Is there anything i can do to get this thing back to fully working order? (I'm handy with a soldering iron if that helps, although I'm not fully convinced it's a contact issue.)

[goat]

try twisting the leads and knobs while its running to make sure nothing there is doing it. could just be a dodgey inputs or knobs with dust in em.
If that aint it,
rip the top off and  (unplugged) and see if there are any loose components and or dust n shit.
Im not sure if there's anything in those can still hold enough to give you a good boot after being unplugged, so maybe leave it for a few days unplugged and find out, before you do anythin to it.
if you arent sure man, dont fuck around in there, ya dont wanna get a good boot off anything. It can hurt!

Ive had shit before that's done the same thing, mainly guitar pedals, where the solder cracks and stuff gets loose.
If its taken a few hits and is old, chances are could be that.

sounds like you proly know all this anyway, just thought i'd chuck in me 2 cents worth. Im bored. Hope you fix it.
 

[cyanide_christ]

If it's not a dodgy connection (either internal or external) it could be an overheating problem. Maybe crank it up and see if it gets unusually hot.

Probably much more likely to be a contact issue.

[Nosaj]

if you arent sure man, dont fuck around in there, ya dont wanna get a good boot off anything. It can hurt!

I second that one.

[Cynic]

Its not an overheating problem (have tested this) and have tested the outside connections/speakers and it's nothing dodgy there. I've taken off the top and some of the soldier joints to the transformer (i think that's what it is, big black box inside with copper around it) have become dull and a couple even have a bit of rust on them. I might try re-soldiering them, but there's no danger as long as it's unplugged right? Thanks for the suggestions, in return here is an awesome tune for all of you with working home amplifiers to crank http://www.youtube.com/watch?v=VLsw668PVyY

[Mago_Haydz]

but there's no danger as long as it's unplugged right?

nah man, like goat was saying, transformers and shit can still hold enough charge to give you a good old jolt, even unplugged. I wouldnt fuck around too much.

[Jimmy_Mate]

but there's no danger as long as it's unplugged right?

nah man, like goat was saying, transformers and shit can still hold enough charge to give you a good old jolt, even unplugged. I wouldnt fuck around too much.

Its the capacitors in the circuitry that hold the charge - the transformer is just a big lump of iron surrounded by copper windings.


http://www.acmehowto.com/howto/appliance/freezer/check/capacitor.php

You dont have to wait days for it to discharge (despite what the link says) - generally 5 minutes is WAY MORE than what it takes all but the biggest capacitors to drain. Alternatively you can just short the capacitor (either directly or via the method shown on the link) - that will discharge it instantly

[cyanide_christ]

My electronics teacher last year told us about this dude he knew from a car audio place who thought it would be a good idea to discharge a 1 Farrad capacitor with his tongue which obviously blew it to smitherines.

Yep, electricity is fun.

[Nosaj]

Sod beat me to it. It's the capacitors. I got caught out with that.