PCMHiFi wrote:Thanks so much for your advice, and for all of the great information. With my poor soldering skills, I've been thinking for a while about sending it out to have the increasingly brittle patch/ground cables replaced with some top-quality jacks, along with bulb replacements, etc. With your mention of the capacitors, sending it to a good restoration shop is making more and more sense. I can't imagine that even twice what I'd spend on a top-notch restoration for the 72 would buy a "replacement" table I like even half as much. I plan to read up on repair/restoration shops over the weekend, though would appreciate any thoughts you might have there.
Meanwhile, I might get some of the contact cleaner and try Alec's recommendation along with your tip on the VR1 & VR2 pots just to see if I can calm it down. Until then, given what you mention about the microprocessor potentially being ruined by out-of-spec caps, I've stopped using it for now.
It is wise to stop using it for the time being. If I were you I would seek a repair shop who would be willing to recap your table.
I have used a repair facility in NY: http://www.stereorepair.net/
. The hassle is that you have to pack up your gear but they seem to be professional and very detailed about their work. You might consider getting in touch with them and see if they would recap your table for a reasonable amount.
They would need to replace all electrolytics. That's a total of 42 electrolytic capacitors. None of these is the expensive large capacitance type. The largest capacitor is a 2200uF/25V electrolytic. These are all standard aluminum general purpose radial caps and if I remember correctly the total for all of the replacement capacitors was less than $40. Of course your cost would be mostly the labor to replace the parts and do the required adjustments.
I would also get quotes from local repair shops closer to your home. If you have a place close by that does this type of work it is much better than shipping the gear out and having to deal with the problems that can occur during shipment. That plus the extra bonus of starting a relationship with someone you can trust for future repair work.
Not to mention that the DP-72L is not a light item. It would probably cost around $50 to ship it via FedEx Ground.
If you are anything like me you love your table and want to keep it running for a lifetime. I am lucky to have an electronics background and some experience with a soldering iron. I would still like to find a local guy to take my gear to.
Be careful if you attemp to clean the switches in the DP-72L. The switches that you press are sealed type swiches that are on small circuit boards that are fixed to the bottom of a small plastic box structure. The switch that you press has a plastic shaft that contacts the momentary switch mentioned above. It looks like a small plastic cube mounted on the circuit board. I doubt that there is any way to access anything in the switch and if you spray anything in the area of the switch you could be complicating things.
My DP-62L has been running for 30 years and the switches seem fine. Every once in a while I have to press one of them more than once but I think thats just the expression of time. The speed switches themselves would probably not have anything to do with the symptom you first described. Both the 33 and 45RPM switch are directly connected to pins on the speed control microprocessor and they control which clock pulse it uses internally to lock onto the speed desired.
A momentary switch problem should not cause a speed problem. They are momentary type contact switches to begin with and the circuit does not depend on any current flowing through the switch for anything. The processor simply detects the pressing of the particular switch and internally switches to the proper clock pulses. If you press the 33 or 45RPM switch repeatedly it will not cause the processor to do anything, It will simply stay at the speed it is already set at.