killer1997
New Member
Hello. I have a Denon DP57L. The turntable is generally functional and only required minor maintenance and cleaning after purchase. However, my enthusiasm did not last long because I discovered, when the turntable was working in complete silence, that at speed 33 there was a rhythmic rattling. At first I thought it was a mechanical problem, so I cleaned the engine and lightly lubricated the axle. During operation, you can hear the engine gently adding power, hence the rattle, but the revolutions are stable and there are no speed jumps when playing records. For speed 45 everything is fine. Following the service manual, I connected the oscilloscope to the TP1, TP2 connectors and ground TP4. These connectors have a triangle signal and a pulse signal from the platter's magnetic stripe sensor. While at speed 45 the triangle signal stabilizes when the turntable gains speed, it remains very stable. For 33 this signal floats. I thought that maybe the platter had a damaged magnetic strip at some point, which was causing heart rate disturbances, but I have a second copy of the DP57, I replaced the platters and the effect was the same. Later, my suspicion fell on the processor itself, I even tried to solder it from the second copy (100% functional), but it also did not bring any result. I don't know where to look for errors, I've run out of ideas for now and I'm counting on your help, for which I thank you in advance.
Ps. I tried to set the pulse signal as recommended in the service manual, i.e. approximately 60-70% of the triangular signal filling.
Ps. I tried to set the pulse signal as recommended in the service manual, i.e. approximately 60-70% of the triangular signal filling.
