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Realistic STA-20 HUM

G

Guest140

Active Member
I took a chance and purchased a Realistic sta-20 that is in a very sorry state and needs a lot done to it, on switching on there is a noticeable hum through the speakers and the right channel is lower in volume, adjusting the balance does not cure this, I have cleaned all the switches and checked the earth screws and been over the circuit boards looking for dry solder joints but the hum remains its the same on am fm and phono.
Has anyone any ideas on what it could be?

Thanks
Stephen.
 
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Stephen Dare said:
I took a chance and purchased a Realistic sta-20 that is in a very sorry state and needs a lot done to it, on switching on there is a noticeable hum through the speakers and the right channel is lower in volume, adjusting the balance does not cure this, I have cleaned all the switches and checked the earth screws and been over the circuit boards looking for dry solder joints but the hum remains its the same on am fm and phono.
Has anyone any ideas on what it could be?
Click to expand...
There's a high likelihood that the power supply filter capacitors have dried up and failed. Gear of this vintage almost certainly would benefit from recapping, i.e., replacing all electrolytic capacitors.
 
+1 on the recap. I picked up on of those a long time ago and did a recap on it maybe 10-15 yrs ago. Not a lot of parts and not bad to work on except for 1 stubborn cap that is still in there. I did take loose a big pulley from the tuning cap in order to keep the string away from the soldering iron though I believe it wasn't necessary to unwrap the string, just set the assembly aside for access to a number of caps.
My daughter used it through high school, college and post grad and is still using it today. Not the last word in hi fi but works reasonably well with minimus/optimus 7 or 77 speakers.
 
Thanks for replies, I will have to take it to the shop as I'm useless at electrical work but at least while it has been apart it has given me a chance to do it up a bit inc sanding and re-staining the wooden case, cleaning off years of nicotine and replacing bulbs, cleaning switches etc, I had to make part of the plastic side panel as the bottom corner was missing and if you don't look too close it looks good.
I really enjoy rebuilding things and spent a long time getting my Thorens TD 160 back to scratch but apart from a bit of rewiring and replacing anything obvious, the electrics surpass me.
Thanks again, Stephen.
 
Stephen Dare said:
Thanks for replies, I will have to take it to the shop as I'm useless at electrical work but at least while it has been apart it has given me a chance to do it up a bit inc sanding and re-staining the wooden case, cleaning off years of nicotine and replacing bulbs, cleaning switches etc, I had to make part of the plastic side panel as the bottom corner was missing and if you don't look too close it looks good.
I really enjoy rebuilding things and spent a long time getting my Thorens TD 160 back to scratch but apart from a bit of rewiring and replacing anything obvious, the electrics surpass me.
Thanks again, Stephen.
Click to expand...
I have been trying to find a good company to do a repair but can't find anyone who will take it on, the big shops don't see enough profit in it and the small man just doesn't advertise.
there also seems a wide range of prices, as a rough guide, what should I have to pay?
 
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