Denon Turntable DP 15F runs backwards !

HERE YA GO!
When you pull off the platter look for a thing that looks lake a tape playback head. If its loose you have one of your answers.

The inside edge of the platter is coated with a substance (usually a dark brown) that is for all effects and purposes a tape coating. Into the tape coating there are speed pulses that are recorded by Denon when that platter was manufactured.

The aforementioned tape head reads the recorded information on inside edge of the platter and performs its electronic magic to lock onto and regulate the speed.

Sometimes the servo (or tape head) comes loose and backs all the way off. There are openings in the platter so the servo head can be adjusted. If you have an index card place that card between the servo head and the inside edge of the platter (through the platter openings). Move the servo head and tighten the two screws when it has been "gapped".

If this does not help then you have one of two problems. Either the information recorded on the inside edge of the platter is history (in which case that TT is history) or the electronics need recapping.

Its a high probability that the electronics need recapping anyway but check out the servo head and see if it needs to be adjusted.When you pull off the platter look for a thing that looks lake a tape playback head. If its loose you have one of your answers.

The inside edge of the platter is coated with a substance (usually a dark brown) that is for all effects and purposes a tape coating. Into the tape coating there are speed pulses that are recorded by Denon when that platter was manufactured.

The aforementioned tape head reads the recorded information on inside edge of the platter and performs its electronic magic to lock onto and regulate the speed.

Sometimes the servo (or tape head) comes loose and backs all the way off. There are openings in the platter so the servo head can be adjusted. If you have an index card place that card between the servo head and the inside edge of the platter (through the platter openings). Move the servo head and tighten the two screws when it has been "gapped".

If this does not help then you have one of two problems. Either the information recorded on the inside edge of the platter is history (in which case that TT is history) or the electronics need recapping.

Its a high probability that the electronics need recapping anyway but check out the servo head and see if it needs to be adjusted.

Some thoughts...

Having the sensor "too" close to the inner platter rim/tape will cause the motor to run backwards (at least this was the case with a JVC deck I got running a long time ago).

Do not touch or attempt to clean the inner plater rim (treat it gently).

If it's a bad motor run/start cap the Denon's I've seen had two identical caps on the board (which can be a bit confusing) with one being the "run/start" and the other being "speed control".

Just a fiddler and not a tech.

DeKay

Someone suggested cleaning the tape coating the inner rim of the platter with alcohol.  I am not sure this is a bad idea, but it might be. The guiding principle is that that tape coating is essential to proper function of the speed control system.  If you scratch or break the tape, the turntable is probably toast, as someone else did say.  So, I would first inspect that coating.  If it’s filthy, you might try to clean it with something gentle.  Also, as someone else said, the tapehead-like thing that reads the tape may be loose.  But I do not know per se how that could lead to the platter running in reverse.  These decks use a single integrated circuit that controls speed based on input from that tape head.  The IC may have been damaged.