Today at work, we were throwing away some old junk, and I came home with a Sony STR-AV210 receiver. (I was pretty excited about it, because I’ve had a pair of speakers lying around with nothing to attach them to.)
After laying out the connections between my TV, VCR, PS2, receiver, and speakers on a diagram, I bought a bunch of cables and came home to find out the left channel on the receiver is toast. I have to turn the volume up to 4 to make it as loud as the right side is at volume 1, and then the sound is all distorted. The same thing happens with either speaker (i.e. the speakers and wires are fine), with both “A” and “B” outputs, and with the built-in tuner as well as the audio input from my VCR.
I looked at new receivers online, and they seem to start around $150. I’d like to get this setup working, but I don’t want to spend that much.
Is this the kind of thing I could fix myself? I have access to a scope and signal generator, and I work with some electrical engineers, but my own experience is limited to using a multimeter and soldering.
If not, is it likely that I can get it fixed for less than $150?
I don’t really need a tuner or input switches, so if it’ll cost a lot to get the receiver working, is there a cheaper way to amplify my VCR’s audio to connect these 40-watt, 8-ohm speakers?
Bring it into work and plop it down on one of the EE’s workbenches, along with a six-pack of beer. Say, “There’s another one of these on ice if you can fix this thing.”
There’s probably a good reason it was in the junk pile. I I did a web search to see if I could find anything about its original value, and I didn’t find anything.
You can probably forget about getting a repair place to fix it for less than $150. Hell, they’ll probably charge you a flat $80 or so just for opening the cover and gazing into it. Any parts it needs will chew up the rest of the money, so instead of having a new, reliable receiver that’s under warranty, you’ll have an old, marginal, soon-to-break-again receiver, for the same money.
Not much info to go on here, but it doesn’t sound like anything too serious. Any blown transistors in the driver or output stages will prevent the protection relay from engaging, so it’s almost certainly not that. My guess is a dirty volume or balance control. Is the symptom also present in the headphone output? What the line level outputs (record outputs to tape)?
Attrayant: The line out seems fine. I don’t have an adapter to hook up headphones… the best I could do was connect the headphone output to a walkman’s microphone input, but I only managed to record a buzzing noise.
I’ve also noticed that when I turn the receiver off, it loses all the radio presets. This isn’t looking good.
Does it have discrete transistor outputs or an “STK” style chip. If’n you see yourself a Big Black 8 sided but not octoganal chip. Odds are that’s your bad part. Many newer (read last 15 -20 years) amps use these chips. They are easy to replace and not so expensive. One place to get replacements is MCM electronics.
Well, I visited a pawn shop and got an old MCS receiver for $40. It seems to work except for the AM tuner, but I’m not conservative so I don’t listen to AM radio anyway.
I’d still like to take a shot at fixing the Sony, if it’s possible… it can’t get any more useless. I’m a little hesitant to open it because of the high voltage warnings, though. If it can’t even hold the radio presets when I turn it off, is there really anything in there that will shock me?
Well, if I can get it working, I could easily get my $40 back (and even turn a profit, if I keep the MCS). I wouldn’t mind poking around in it at work after hours, if it won’t kill me.
You can narrow down the problem pretty quick. Take the line out (or tape out) signals to the other reciever. If they sound ok then the problem isn’t with the main sound generating circuitry. Next try a pair of headphones. If those work, then the problem is only with the output amplifier stage. If not then its in the pre-amp. Watch out that the headphones aren’t connected to the final output via resistors, I’ve seen that setup too, and if that’s the case then the headphones will be munged if the output stage is gone too.
Back in my college days, I had a Radio Shack receiver (they used to make some fairly decent stuff) and a roomie who was a geek in myriad ways, electronically being one of them. One channel on the receiver died, so I did pretty much what yojimboguy suggests: I dropped the thing in the geek’s lap and set a frosty-cold Miller long-neck on his workbench. Several hours, one trip to RS, and a few beers later, he gave it back to me. Total cost: about $1.60. (Output transformers are cheap!)
I have to turn the volume up to 4 to make it as loud as the right side is at volume 1, and then the sound is all distorted. The same thing happens with either speaker (i.e. the speakers and wires are fine), with both “A” and “B” outputs, and with the built-in tuner as well as the audio input from my VCR.
