Monday, June 13, 2011

Fixing a Speed Issue with the Dual CS-5000 turntable




My Dual CS-5000 turntable has been having speed issues of late. The platter speed would start out slow and take time to get up to speed. Sometimes in the middle of an album, the platter speed would also minutely drop, effecting the tone of the music. A quick perusal of Google and I found that the power supply capacitors for the DC motor are known to go bad. Since electrolytic capacitors of this sort are inexpensive, I decided to go ahead and replace the originals.

To replace the power supply capacitors - first remove the lid, mat and turntable platter. Also remove the rubber belt at this time. Make sure the turntable is unplugged before proceeding.

The capacitor circled in GREEN is a 2200uF/25V unit. Polarity is indicated on the board, but as a note, the positive side is closest to the spindle. Removing it is easier with a solder-braid or sucker - if those tools aren't available, you can pull on the cap and slow ease it out by alternating your solder iron on each leads. Don't go too hot with your iron or you will risk damage to the PCB board.

The capacitor circled in RED is a 3300uf/35V unit. It's built different than the other unit - with three ground lugs on the edge, soldered onto the board. The positive lead is in the middle, soldered in the board. To remove, I cut out the top lugs and removed the solder on the bottom lug and positive lead. For replacement, I tied the negative lead to the topmost ground lug position closest to the spindle. The positive lead was obviously soldered to the original positive position.


I hate modifying or fixing gear that I really like, but any fears were laid to rest when I fired it up after reassembly. Now the turntable gets up to speed faster and doesn't have any tonal variance issues. Hurrah!


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2 comments:

roger said...

Thank you for posting this. I've been having some speed issues with my CS-5000 lately, and this post has been very helpful.

I do have one question: why did you solder the negative lead of the 3300uf cap to the position of the top ground lug that you cut, instead of the bottom lug that you removed the solder on?

I'm a bit of a novice in this area, so please forgive me if I'm asking a question with an obvious answer.

DividebyTube said...

sorry, it has been too long since I did the repair. But I do remember that the 33000uF cap has several ground lugs. For the ground of the new cap, I just used one that was obviously tied to the PCB, not just a mechanical connection.