Denon DP-7F speed, jitter

[illini]

After adjusting the tracking force and checking things out with a test record, I played this table for a few hours then went to bed.

The next morning I played some Angel Witch and realised the speed was slow and fluctuating. Using a test record I found out the jitter was occuring cyclically, at the same position on each revolution. My guess is too much friction, but where?

Does anyone have experience with this problem? I have owner's and service manuals on hand; it's one of the three tables I want to repair.

 

[Dadbar]

I fixed one of these for a friend recently. Your platter is probably rubbing on the surface of the deck. Pull the platter off and you will find the rotor below (it has the spindle attached to it.) The rotor below fits into the spindle bearing and rides on a cushion of air. Oil on the spindle keep a cushion of air below the spindle, maintaining the height of the assembly. Yours is probably riding too low because the oil has dripped down or dried out and now the whole assembly with the platter is too low and dragging on the surface of the deck.

Pull the spindle out and clean it with some alcohol. Use a q-tip and clean out the spindle bearing. Dip the bottom of the spindle in some heavyweight oil (like motor oil if you have some) and replace the spindle in the well. It should maintain a nice air cushion below. Put the plater back on and you should be back in business.

Good luck!

 

[illini]

Thanks for the info, the repair worked. Here's what I did:

1. removed motor assembly
2. removed spindle
3. cleaned and lubed spindle with ipa and 10w-30
4. reassembled
5. tracking force readjusted; has two steps: first at about 1.2, then 1.38 (final force when playing)
6. tested for a few hours; works great!

I didn't see anything wrong with the spindle, but I suspect using a record weight may have contributed to the problem.