Stereo parts

[mikebike]

my buddy gave me an old stereo reciever, with the left channel out.

i thought id poke around and see if i couldnt make it work.

well, most of the larger caps appear to be exploded, so i geuss ill snag some parts!

man that transformer i beefy, maybe relocate it to an amp project some day?
cool knobs i geuss.

but my big question is the STK083 power amp chips, im hoping to salvage them (and there huge heat sinks) an build them in to my casio build to power a small internal cabinet.

i found a data sheet that says 15 to 40w, should be enough to bump a small room.
imagine 2!

any ideas? is it worth the work of salvaging these to build a little power amp, or are there smaller more efficiant power amp chips out there nowa days.

also, they need 32v+/- probibly gonna be an issue

heres the data sheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/90370/ETC/STK-083G.html

some pics below

[expanoncolin]

You'd probably do better using the LM3886 or something like it, but if you want to use those chips, I'd try to find a circuit and copy it.  Depending on which caps are bad, you could use the circuit in there, or at least the power supply to get +/- 32V.

-Colin

[mikebike]

the transformer is so big though!

id have to build a seperate head unit for sure. though if i can get both sides working, it'd be a nice little stereo power amp.

maybe i can find some schemes of the reciever.

am i right that these are exploded? all the bigger caps have a dried out yellow goo around there base

[mikebike]

oh

[crochambeau]

The goo doesn't look like electrolytic guts to me, it looks like it was manufactured that way. I'm guessing they "glued" the caps in place prior to hand soldering (assembly line fashion), so when they flipped the PCB the caps didn't spill everywhere.

If you power the amp up without speakers on either channel, and take a millivolt reading on each speaker output, what do you read?

Might be as simple as a faulty relay, or dirty controls. I think a lot of those STK ICs are the home stereo equivalent of CEM ICs to us. I'd heed Colin's advice, go with something in production to power the Casio project..

In the meantime, that amp may be repairable.

[mikebike]

thats kinda how im begining to feel.
ill repair the power cord and measure the outputs like you sugested.

should i have a signal going in to the amp when i measure?

[mikebike]

got 20 mv on the left, and nothing at all on the right

[crochambeau]

should i have a signal going in to the amp when i measure?

No signal in, volume controls at 0.

Does this have relay protection on the output? 0 mv is REALLY difficult to achieve, sounds like a disconnect to me.

[mikebike]

hey man,

i didnt see a reply to this post! sorry

i didnt notice any relays, but i wasnt looking!
i had it on tape with no input, i dont know if the volume was at zero, ill take another look today