Author Topic: Slow spinning motor on Philips TT  (Read 335 times)

Offline Tom

Slow spinning motor on Philips TT
« on: January 24, 2021, 08:51:37 PM »
Hi everyone.

I am a little bit lost here, I have a Philips Af22 TT that drops into a music centre and slowly, over the months, I noticed it started playing slower and slower. It is not even playing at half speed at the moment.

I checked the belts, Both seems fine
Cleaned and washed belts, etc. No buildup on pulleys. Turned TT upside down, no gunk or any dust or debris.
Spindle comes out via a small clip and is clean. It is dry and shiny and I am not sure if this needs oil but spinning the platter by hand it is clear there are no problems here.
Found and cleaned internal adjustment pots and also the main speed adjustment pot and I can see when turning them that they are indeed working and speeds up and slows down according to my adjustment but still the TT probably only reaches half speed on both 33 and 45 when turned fully clockwise, not even putting it onto 45 makes it spin close to 33. With 33RPM selected when I turn the main adjustment knob to the negative the platter almost stops.
Motor spins freely with my fingers once belts are removed.
Could it be the motor itself? 

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Offline marantz123

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Re: Slow spinning motor on Philips TT
« Reply #1 on: January 27, 2021, 02:37:11 PM »
Measure the DC voltage feeding that motor and compare it to the voltage spec of the motor. It seems that the motor is losing power (current x voltage product). Could be a bad capacitor or a resistor in the power circuit gone out of spec. From what I read in your post, it seems that this may have a similar setup to that of the Pioneer Rondo 3000 (KH model) with a direct-DC driven turntable with a basic regulator circuit.