Turntable Speed changing on Beogram 4002 (Related to my earlier post on the same 4002)

27 replies

I have a Beogram 4002 that is all working properly except that the speed which the platter is turning, slows down and speeds up on occasion after playing fine for 15 minutes or so. Sometimes it will correct itself but other times seems to stay at the same slower speed. I have put on new belts, replaced the capacitors, switched out the R15 adjustable potentiometer with one I cleaned one from another board and switched platter motors from another unit but none of these things has fixed the problem. Also I have tried adjusting the speed of the R15. I looked at the recent post on this forum by Step1 regarding the Beogram 4002 running slightly slow and tried to see if I could learn something from that. One question I have is the servo motor possibly involved here. Sorry to say, but I was a little confused if that was part of that discussion by Step1. Also Jacques mentioned in that post adjusting R1 and R2 but I am not sure where those are or if he might have meant R14 and R15. Could you let me know Jacques if you are reading this? I do have another servo motor I can put in place of the one on this table if that might be worth trying. Should I be considering cracked solder joints as well?

 

John

Oxidated relay contacts ?
Dirty speed adjustments (the fingerwheel driven potentiometers) ?

Martin

Thanks for the reply Martin,

So I take it the servo motor is not a suspect. Could you point me to right direction to look for where the relay contacts can be found?

John

 

Hello John,

I changed the relay on my 4002 type 5513, that was all which was needed to fix the problem. It is located beneath the control panel 🙂

-Søren

Hello Soren,

Thanks for your reply. Based on Martin's suggestion that it could be a dirty or a bad potentiometer in the control panel I switched out the panel with another I have and I swapped the PC board below it based on your suggestion with a board from my salvage table. The relay I am assuming is RL1 and is the clear plastic box with a wire coil in it on that board. I put it back together and everything ran at the correct speed for about 35-40 minutes and then started to slow down and warble off speed.Seems like maybe this is related to something warming up.

I don't have an extra good main PC board for a 5513 so can't switch that out to see if it is something on the main board. I guess it is possible that either the second control panel or the second relay could be bad but not sure how to proceede. I do have a 5523 that I am restoring so I will check to see if the control panel and board below it appear to be the same as the ones on the 5513 and see if that makes any difference.

John

Well, I decided to try the easy thing and switch the platter motor with one that I was sure was a good one before trying different control panels or PC boards again. After several several hours of consistent playing with no problems, I began to suspect it was the platter motor. I put the other motor back in and the problem started up again which confirmed that it is the motor. I had taken this motor apart because if was jammed when I got it but I thought I had got it back together OK. I have taken it apart again cleaned and lubed it but still no luck with the motor running at a consistent speed. Not sure why that is the case but at least I know what the problem is now.

John

Good luck finding another motor

 

Location: Mexico city

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I haven't found a new motor yet so I tore down the faulty motor and tried to clean and lubricate it one more time and put it back together. This table was working fine except for the motor. For some odd reason the motor ran backwards this time and then blew a fuse. I took the motor apart and reassembled it and put it back into the turntable and now the speed of the turntable is going way too fast, not just a little fast but sounds like twice as fast as it should be playing and is closer to 78 rpm. I tried adjusting the trim pot for 33 rpm but that did not fix the problem. I switched the good motor from my other table and had the same result so it is not the motor. I have no clue what I have done here. I switched out the control panel for the thumb 33 and 45 rpm adjustments and the board that has the relay under the control panel but that did not fix it either. Any thoughts would greatly be appreciated.

Not sure about the Beogram but these symptons commonly occur on Rega Planar 3 and P3 turntables (speed instabilty and motor rotating backwards). It is never the motor. The problem is the run/start capacitor and associated resistor on the motor PCB. That is where I would look.

I was looking at the service manual for where I might start looking regarding the suggestion by Telecine. I assume that it is an issube that relates to the tacho control. I do have a spare board that is not working that I could canabalize parts from if someone has an idea where that I might start replacing with what parts. I don't have a scope so this is the best I can do is just replace things till I get it working again.

Thanks,

John

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