I have 3 Denons but not your model and I like them very much. I would suggest not buying the turntable if it doesn't work.
I would pass on it. It may be a simple recap which would cost you $150-200 bucks. Or it could be one of those proprietary chips in that case you have a beautiful paper weight. I would look for a working one. They can be found starting around $750 up to around $900. If you can find a working DP-75 or DP-80 for these prices jump on it. These are now around $1000 and up.
That's a bit much for something that doesn't work. I believe that Denon built their own motors and Denon certainly has a reputation for building robust gear. It's got to be something silly wrong with it. (Defective switch, fuse, etc)
If you can get it for half that cost I would consider it. Take it to a reputable shop and have it repaired and gone through. Denon tables are superb performers and for the most part exceptionally well made. So, yes it would be something you could keep long term. You could always add an outboard arm pod and a second arm if you wanted to upgrade a little.
(make sure the platter isn't seized, if it is then pass)
The fact that you can still find a DP80 (or a DP75) for less than $1000, albeit in an unknown state of repair, is why I don't sell my mint DP80 that has been completely re-capped and re-transistored and had its control chip replaced; no one would pay a fair price in relation to its performance. I would hold out for either of those two over a DP60, especially if the DP60 has a demonstrable problem such as the one you describe. The DP80 is one step away from Denon's all-out effort, which was intended for professional use, the DP100.