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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 11th Sep 2023, 8:06 pm   #1
sourbiscuits
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Unhappy Sony TCM 5000EV motor noise after belt replacement

Hello everyone. I recently got my second Sony TCM 5000EV unit. It clearly had old belts. After I opened it and replaced the belt it now has a high pitched motor noise in the background. I am pretty sure it didn't have it before I replaced it. It was just a clear white hiss. Now I mention this is my second unit of this exact model. The other one I have has the same issue. I thought it's just part of the natural hiss it produces. I am now pretty convinsed I must have produced this problem somehow while opening and closing the PCB standing in between the mechanism and me. I had a thread about this in the past and since it was closed, I am posting again with a call for help. What have I done wrong to cause this issue twice in a row?

I am sharing a link to showcase how it sounds. I am recording with the tone knob all the way up (high) and am slowly increasing the speed control. At some point near the end the unit stops the motor as there is no cassette inserted. Then the buzz goes away.

https://drive.google.com/file/d/12dD...ew?usp=sharing
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Old 11th Sep 2023, 8:30 pm   #2
Graham G3ZVT
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Default Re: Sony TCM 5000EV motor noice after belt replacement

You probably needed to disturb some wiring when moving the PCB. Try to route any wires excatly the way you found them.
Typically the screened cables to the heads should be dressed well away from the motors.
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Old 11th Sep 2023, 8:31 pm   #3
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Default Re: Sony TCM 5000EV motor noice after belt replacement

Check all the metal work - motor, deck plate, heads, any metal case - is securely earthed and connected to chassis. Sometimes there are springy metal strips that make contact on assembly, and that may need retensioning
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Old 12th Sep 2023, 7:00 pm   #4
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Default Re: Sony TCM 5000EV motor noice after belt replacement

Hey guys. Thank you both for the tips. I luckily took a photo of the PCB before I removed anything. There are indeed a lot of wires going around and everything was very tight when I started. All wires are basically back the way they were but that does not seem to make a difference. The PCB fits in a very exact manner when placed in, and I could not locate anything that seems to be off.

A few observations I made:

When I power the motor on (playback, FF or REW) the noise is there. Even if I turn the volume knob all the way down, the noise is still there. I cleaned the speed knob with contact spray and it now adjusts the speed all the way as designed and I can clearly hear the noise.

The tone knob seems to affect the frequency of the noise with the volume knob all the way down.

If I engage the record button (only) there is no noise (only hiss). If I then engage the playback along with the rec, the noise is there, but slightly louder. Volume and rec knobs are all the way down.

I also powered the motor with the PCB slightly lifted and that has no effect.

All tests were done without a cassette inside. I also compared everything on both players and they seem to be set the same way. No components are in contact with the chasisis.

I have not taken the entire thing apart. I only lifted the PCB from to reach the belts on the transport. Only disoldered two wires to do that.

Could the problem lay somewhere underneath? Do you think the playhead is picking up the frequency or is it the amps? I am really stuck with this and can't seem to think of a solution
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Old 14th Sep 2023, 5:19 pm   #5
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Default Re: Sony TCM 5000EV motor noise after belt replacement

I did some more testing and thought I'd drop an update. So I tried taking the belt off and then engaging the motor. Basically, if the belt is not in contact with the motor there is no noise coming even if the motor is spinning. I event tried with the old looser belt. If I hold both wheels, the motor runs and as the belt is in contact with the motor, it's trasferring the noise. If I fully remove the belt, I can hear the motor resonating more as nothing is in contact with it. In the audio sample provided, at first the resonanse is very subtle. If I touch the motor with my hand a bit, it starts resonating a lot more. So with all that being said, I think the problem comes from the motor? The PCB is as shown on the photo, with the difference that I hold it with my hand and no components are in contact with it.

I can't seem to figure out if this is not a motor problem, what else could it be then?

https://drive.google.com/file/d/19DK...ew?usp=sharing

I am also attaching a photo of the wiring when I first opened the unit. I don't believe it was ever opened.
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Old 14th Sep 2023, 10:13 pm   #6
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Default Re: Sony TCM 5000EV motor noise after belt replacement

It sounds like you have mechanical noise due to the spinning motor, that's inevitable naturally, plus you have electrical noise caused by the motor but emanating from the loud speaker, that portion is affected by the tone control.

Try fitting the PCB into its correct position while the belt is off the motor shaft, does the noise that is affected by the tone control return?
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Old 15th Sep 2023, 6:57 pm   #7
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Default Re: Sony TCM 5000EV motor noise after belt replacement

Hi Graham. I did try with the PCB inside and the belt detached. The noise is basically the same. It does get affected by the tone knob, but just cuts off the high end and it's still there. Just to clarify, the second audio sample is not from the output of the unit. I just recorded it with a microphone close to the unit. The noise is in all outputs - headphone, line and speaker.
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