Another Dual CS5000 question

Old Vinyl

Old Vinyl

New Member
I purchased a mint Dual CS5000 about 10 years ago, part of my addiction of buying too many turntables. At that time I purchased a new belt to help lock in the 33.3 RPM but the belt was too wide or thick and was worse than the old belt. I ended up putting it in storage.

Well, with 7 turntables laying around the house, I have decided to sell the Dual. After reading numerous posts I purchased 2 Thakker belts, replaced the RCA connectors, cleaned RPM switches and other connectors, new silicon grease for the tonearm, and cleaned the pulleys. I did not replace the large capacitors. After starting up I was surprised that within a few seconds the motor synched and was able to play a record. I was surprised how good it sounded. I have a low mass Ortofon OM30 which seems ideal. Using the iPhone RPM app its running at 33.45 RPM and wow and flutter .16 which seems pretty good.

I went one step further and lubed the main spindle bearing with Rega hypoid oil. The old oil was there but not very much. To my surprise, the motor wouldn't synch anymore and when testing with iPhone app it shows he platter spinning 34.6 RPM while trying to lock. I put light pressure on the rim of the platter to slow it down a bit and the motor locked in right away. It seems the new lube made it easier for the motor to spin freely and was running too fast to lock in.

Does this make any sense? It's too bad Dual didn't have fine adjustment for RPM to allow the motor to synch at the proper RPM. Anyway to slow the motor down on these things to allow them to synch? Would replacing the large capacitors have any effect on RPM?


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I had the same problem with mine but it stopped doing it, and I thought the belt just stretched out a bit. Use thicker oil on the spindle, or grease. Dupont makes a great white lithium grease with Teflon. Comes in an aerosol can.
 
I tried some lithium grease. The RPM while trying to lock went up to 35-36 and wouldn’t lock. It’s as if the electronics sensed this and tried to spin faster to compensate. Strange beast!
 
I can't believe oiling the spindle would have any impact. Has to be a coincidence with something else. I would look at the belt - if you have another, try it. Even try turning the one you have inside out. The CS-5000 is real fussy when it comes to belts. As for those caps, they are nothing but trouble and change them. When they go, they also take out a resistor on the main board (I think that it is #7 - but that's from memory).
 
Bill, you are correct about the belts. My "new" Thakker belt must have stretched during my various tests. This morning re-oiled my spindle again with a lighter weight oil, Mobil Vactra #2 which is a machine tool slideway oil rated ISO 68.
Upon startup, the green light kept on flashing even with the lighter oil. I noticed the belt did seem looser then when I first installed it and remembered a trick to put the belt in very hot water for 15 minutes. Put the belt back on and
its perfect! Locks in after 2-3 seconds every time. I never realized how important the belts are on these tables, even cleaning records could possibly stretch the belt in time causing the inability to lock.

I have a couple of capacitors with the correct specifications but what I have are Nichicon UFW series which are audio grade. I should have gotten the UPW series which are power supply caps.
I should order some of the UPW capacitors and replace the old caps.
 
This morning I tested the CS5000 and it’s behaving strange again. Won’t lock in after sitting the night. Starting at 45 RPM and dropping to 33 it eventually locks. But at 33 it usually won’t lock. Is this most likely the large Frako caps acting up intermittently?
 
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