Counterpoint SA5 Phono Channel Out... Help!

[leviathon]

Well, it's been over a year since my last DIY fix, and I am hoping the solution may be the same. However though the symptom started the same, the result is different. Help!

The rather poor (Counterpoint) engineering of having the tube mounting board at a right angle to the main board, connected only by solder joints has created some havoc in the past.

Last time (about a year ago) I finally unsoldered the entire board, nicely cleaned and put it all back together and voila! Excellence!

The other day I went to listen to vinyl and notice a bit of crackling out of the right channel. After eliminating the tubes as the problem, I realized I could create the crackle by wiggling the right angle board.

No stranger to this scenario, I opened her up, and touched up all the solder joints where the two boards meet.

Well, I am always a fan of solder paste, and I obviously used too much, because when I put it together, the sound was much worse and through both phono channels now. The solder paste overuse/run off was a theory.

I used a de-flux spray and nicely cleaned around all the newly soldered joints. I also touched up a few joints here and there that looked a little weak.

Everything worked almost perfect when I put it all back together. Just a little bit of crackling through the "right channel". Just barely. So I started to wiggle the right angle board a bit, reversed the tubes just to be sure, crackle was still there... but then "pop" I lost the right channel altogether.

Gaaaaagh!

Where do I begin?

The line stage works fine.

I checked the input cables from the turntable and the problem didn't change.

The mono switch does allow music to come out of both speakers, if that helps the diagnosis. Otherwise in stereo the right channel does not work.

Note though, when I turn the pre-amp way up, with no signal, I do hear the slight ocean hiss through both channels. I have always had this. The line level was always deadly quiet.

I don't see any visible problems.

I am just wondering if I should accept my destiny, start over, disconnect the right angle board, give it a good clean, and resolder all the points over again? Or perhaps there is some else easier to check before I do this?

As usual I was gearing up for some Easter Weekend late night listening.

Sigh... what's that buzz, tell me what's happening?

Many thanks in advance for you kind help.

Regards,

Ed

 

[Ken Newton]

You don't mention what other components are on the right-angle board besides the tube. While the noise when "wiggling" the board are signs of a bad connection, it may be a bad solder joint of some component on that board, and not necessarily the board-to-board connection. Assuming that there are only a few components on the right-angle board, and that you don't have access to an o-scope with which to trace exactly where the signal is lost, I would fully de-solder (use a 'Solder-Sucker' tool to remove the old solder), and then, re-solder the joints of EVERY component and connector on the right-angle board, and also the relevant connecting joints on the main-board. Do not merely touch-them-up. BTW, you shouldn't need to add solder flux in the re-soldering process. The solder itself should contain enough flux if you are sufficiently pre-heating the bare joints with your iron before applying solder.

 

[leviathon]

Thanks Ken

Yeah I had a panic attack. Cooler minds prevailed and I have now since realized I should start with removing the right angle board.

I have now done that. Everything has been cleaned.

I will check my solder flux content and iron temperature and work on this very slowly and carefully.

I am sure that's all the problem will be.

Thanks for the advice.

I have attached some pics. Off to the office now and back at 'er tonight.

Regards,

Ed

 

[leviathon]

So far so good. Everything bag together. And all appears to be working okay

Nice to have a place to vent. (Wives just don't understand!)

Happy Easter,

Ed