Need help fixing a Setton RS-660

[theblackknight]

Hello,
I am working on a Setton RS-660 stereo receiver.

It sat for 15 years before I powered it up a couple days ago. The contacts were very dirty, so I cleaned them and now it works OK.

I also changed the PS caps on another Setton(the BS-5500 power amp) which drastically improved proformance. $90 worth of caps. it was absolutely necessary in this case though--they were oozing black gunk evrywhere. I also have another stock BS-5500(I have 2- a recapped and a stock) which doesn't sound nearly as good as the recapped one.

normally most people dont change them in vintage stuff. even though the RS-660 still works do you recommend it? would having the RS-660 sit like it did for 15 years dry out the caps?


also--the RS-660 flickers and buzzes for the first ~15 seconds after power-up. this is AFTER the protection has clicked off. then, it stabilizes and works OK. I'm sure this is not a power switch problem as the power switch was already replaced--the power switch was the "achilles heel" of the RS-660 and other setton receivers. it was a problem waiting to happen, every setton receiever I have seen either has a bad one or a replacment. my uncle(the owner of this RS-660 that Im fixing) said that it has always done this flicker and buzz thing except when he first got it.

Im thinking is might be a power supply problem. should I worry about it or just leave it and let it stabilize on it's own like it alway has?


Thanks,
Henry

 

[theblackknight]

Bump!

 

[dshoaf]

Never worked on Setton stuff. I suspect this was due to not that much of it being sold in the US - at least where I came from.

I tend to go on first hanuches re:symptoms reported. My first thought was for anywhere there's a mechanical connection would cause that sort of flickering and buzzing. Look for connectors, crimps in those connectors, etc.

Also look for a bad solder joint somewhere that would affect both channels - it does this one both channels, right?

Lastly, use a wooden probe and push on the circuit board in various places to see if you can recreate the problem at will. The key to intermittents is to get to the point where you can recreate the problem and then narrow down where you can make it happen. Then look in that area by pushing and pulling components to see if you see a bad connection.

Hope that helps.

Cheers,

David

 

[theblackknight]

I believe it is in both channels.

my uncle keeps the buzzing away by clicking it quickly to "B" speakers and then when the flickering stops he clicks it back to "A' where it plays.

my only concern is that the problem is just so consistent. you would think a loose component or bad connecttion would less less likely to do this.


I will try the wooden probe thing you said.

Thanks!
Henry