Technics RS-DC10 background hiss/distortion after capacitor repair

Recorders, Players, etc.
1

Hi,

I’ve been working on my RS-DC10 which I received in non working order. It had the common capacitor leaking issue.

I removed the offending parts and checked the boards, I didn’t see any major corrosion damage (just light surface damage). After running the board through the ultrasonic for a few minutes then giving them a brush, I was unable to see any broken tracks or faulty parts. Some tracks had bubbling to the top layer of PCB which was to be expected, I tested each suspicious looking track and the components the tracks led to, mostly resistors. No problems found.

Upon reassembly, I had good audio signal on the left and right channels playing analog cassettes (I don’t have any digital cassettes yet) however the right channel had hiss in the background and the occasional light pop/crackle. This could generally only be heard on a silent section of the tape. It was enough to register on the VU meters. The left channel also had the issue but to a much lesser extent.

I removed the boards again and had another thorough inspection, I scraped off all visible white residue and reflowed some possibly poor soldering on some parts.
Upon reassembly, the right channel is now worse. The audio signal has dropped about half and the hissing/crackle is very obvious. The left channel remains the same as it was previously.

Another problem it’s always had since I have used it, it will randomly switch between analog and digital tape source when playing an analog tape or even when it’s just sitting there idle with an analog tape loaded. Sometimes it would play through several tapes and not do it once, other times it would do it a few seconds or minutes after starting playback or using the ff/rw, skip or side selector.

I’ve uploaded photos here of each part of the boards after the repairs: https://photos.app.goo.gl/VE1UHjETZj34LfDk8

Is there something I have missed here or can anyone advise anything I can do to try and resolve this? I’m in Australia so upgrading to a new read/write board isn’t financially viable due to the poor exchange rate, and freight costs, plus I don’t know if the randomly switching sources problem would be fixed with new boards, unless someone can advise otherwise.

Thanks

2

Hi, and welcome to the forum.

Although the pictures show minor damage, you can’t really tell if the middle layer (there are 3) has been affected. That is why we have switched to new read-write boards.

It would be the best option to solve none working boards, if the recap fails.

The other problem can be solved rather easy. There are contacts at the front of the mechanism, that determine the DCC/Analog switch. After cleaning them, your problem should normally be solved. We use regular contact/deoxit spray

3

I’ve taken another look at the read write board and found a bad trace which ran under one of the capacitors. I repaired this trace however it made absolutely no difference to the performance.

Unfortunately I’ve reached the limit of how far I want to take this machine so I’ll be selling it on and hopefully the next owner can get it up and running