Vintage DD turntables. Are we living dangerously?

I have to agree with Lewm on this one. I made my living for decades servicing all sorts of audio gear. I would regard it as highly unusual to see a chip failure!!

That is worth repeating: I would regard it as **highly unusual** to see a chip failure!!

Usually you see dirty switches and controls that result in poor speed regulation, electrolytic caps failing- that sort of thing.

So I would see an explanation like this as a bid for a lower price on a prospect.

Now, if you live in a tropical environment, the chips are in a little more danger, from corrosion. If you want some simple protection, you can 'pot' the chips with silicon sealer, the clear kind similar to aquarium sealer. I should point out though that in tropical environments the circuit boards in general are in great danger, so usually you have other concerns that far outweigh the chips... In non-tropical environments this is probably not an issue.

These days I do far less servicing than I used to, but I still maintain my own vintage analog synthesizers that I play in my band. They use a lot of unobtainium chips too! I would say the major force that causes the price of such ICs to rise on eBay is mis-diagnosis of other problems in the synth (usually bad connectors and electrolytics)! I see it all the time....

Aigenga, I can tell you this: the main thing that causes speed stability problems is not bad caps but dirty speed selection switches and dirty speed controls. So if you have a variable speed feature this is the first place to look.

Radio Shack makes an excellent contact cleaner that is about as strong as you would want to put on any audio components. A quick shot of that stuff, and work the control back and forth, and its likely that speed stability is restored.

BTW, some machines that lack an external control may well still have an internal control. Figuring out which one it is and cleaning it is a slightly more complex task. At any rate I would not worry about on-board caps so much as I would filter caps in the power supply!

Occasionally certain parts get identified as trouble makers. I've seen a lot of tantalum electrolytics short out over the years. These days if I see them I don't trust them no matter where they are.

I knew this guy that used a pigskin platter pad... he would buy *raw* pigskin at the local slaughterhouse, cut it out and kept the thing in a jar in the 'fridge when not in use, until the bacteria got to it... the LPs tended to get greasy and smelled like bacon.

The idea is that it was 'natural'- natural sound, get it? The slaughterhouse stopped selling to him when they found out what he was up to...

It does seem odd that the owner of a business that thrives on selling used gear would make the statements about dd attributed to him by Henry or Henry's source. Based on the results of my Google search, those Denon chips seem to be available all over Hong Kong, if he would stick his head out of his door. C'est la vie.

This is what I was alluding to in the synth world- its a bid, based on fear, for a higher price- maybe for the cost of repair (replacing an 'expensive' chip that you don't have to replace, but get to make money on), being unwilling to admit to not being able to repair the unit, that sort of thing.

Bottom line is chip failure is the least of your concerns! They literally will be the least likely thing to fail.