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

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

The capacitors and resistors I am referring to would create a small electrical delay in the current to one of the coils within the synchronous motor. (They helps start-up and constant speed and well as the direction of rotation of the motor. The caps are often called start/run caps or phasing caps).

Telecine:

The capacitors and resistors I am referring to would create a small electrical delay in the current to one of the coils within the AC synchronous motor. (They helps start-up and constant speed and well as the direction of rotation of the motor. The caps are often called start/run caps or phasing caps).

The 551x is the newer version with DC motor and far simpler fundamental layout

Søren Hammer:

Telecine:

The capacitors and resistors I am referring to would create a small electrical delay in the current to one of the coils within the AC synchronous motor. (They helps start-up and constant speed and well as the direction of rotation of the motor. The caps are often called start/run caps or phasing caps).

The 551x is the newer version with DC motor and far simpler fundamental layout

Ok but there must be a start/run cap and resistor in there somewhere.

Telecine:

Ok but there must be a start/run cap and resistor in there somewhere.

No, there isn't. It's a DC motor. It ran backwards because when you put it back you changed the magnet's polarities. When you do that, take good care of marking the exact place of the parts because one third of a turn either way (the three screws will always fit because they are 120° from each other) will indeed have it run backwards or at the wrong speed...

Is the motor silent?

For me it will be an electric problem I think. Have you checked for wrong resistor values? Cracked solder joints? Have you replaced the two speed adjusters on the main PCB?

Oh, and by the way, a Rega (a joke to me) has an AC motor. And it is so simplistic that it is way too expensive! When you see the engineering that went into a Beogram or a Technics even, well, I rest my case!

It isn't my deck.

The early BeoGram 4002 decks had an AC motor. Do we know what motor is in this deck? I don't think that OP has stated the model number or motor type.

I agree that the engineering overall is better in the B&O and the Technics than the Rega but that doesn't tell the whole story. There are many ways to skin a cat when it comes to turntables. The Regas have good arms which make up for some other shortcomings.

Hello,

Sorry I did not supply the information before, it is a DC motor, in a Beogram 4002 type 5513 table. I have now switched out the main board with a working one and with a motor that I know is a good one and runs at a consistent speed. I checked what Jacques was saying about the polarity and that was part of the issue, sorry it never occured to me that something would be that simple of a mistane. It is now rotating in the correct direction, the motor however is still not rotating at a constant speed. Previously I mentioned I took the motor apart because one of the bushings had come loose and the pole was jammed in it and the motor would not turn. I have accidentally bent the small wire "brushes" when I put it back togethr and have taken it apart several times to try to straighten them out again the best I can. They are what look like two parallel brass strips, each separated by a microscopic space and they touch on both sides of the rotor when it is assembled. Does anyone have any feedback on what I might try at this point, I suspect I have just taken it a part and put it back together again one too many times. The motor is all that is keeping this turntable from working properly at this point, "my kingdom for a horse."

John

Update. The good news is that I think I have fixed the motor and it is running at a consistent speed. The bad news is the board I thought was fine has two new problems. First the indicator lamp and the pot is not getting power on the 33 rpm adjustment in the control panel. The 45 rpm still lights. I know the 33 rpm lamp is not getting power because if I pull the unit out and put it in my other 4002 it works fine. The other more bazarre problem is that several minutes after the unit shuts off the turntable platter will rotate on its own. It it not the SO switch because the other main board I have when switched to this unit will not have the same problem. It is good that I don't believe in doing harm to myself at this point or to shiny inanimate opjects that go round and round.

John

Hi John,

Well done with the motor. What did you do?

I maintain that there must be something wrong with the stand-by circuit. Did you replace the two transistors I mentioned in the previous thread?

Also I would closely inspect the board for any other cracks/dry joints!

Good luck.

Ps.: I know what you mean...

Hello Jacques,

I had two motors that were not functioning so previously I was switching what I thought were the best parts between them. That is how the polarity thing got mixed up, the cases were not the same on both motors so the 3 screw holes would never align in any position that I was putting them together but I did not know it mattered. So in the end I went back to what I thought was a bad bottom part of the motor and used the correct top that originally went with it. The "brushes" still look a little bent but it seems to work.

Regarding your previous suggestions that I should checko on the stand-by circuit and the transistors, can you possible tell me referencing the service manual what the part numbers are for the transistors and any other parts you were talking about? I am so unfamiliar with how the board functions that I could not tell you what parts are in the stand-by circuit. One additional problem besides the motor starting to rotate after shut off and the 33 rpm lamp not illuminating on the control panel, that I have discovered is the arm now does not lift at the end of record play.

Any suggestions would be appreciated.

John

jfrancis:

"my kingdom for a horse."

John

Sorry I can't help, but maybe you should try "my Horse for a Solution" , sorry sorry

Hi John,

The stand-by circuit is described at page 2-1. Have you already tried swapping the whole control panel? There could be a problem with the 33 switch methinks. Otherwise, have a look on the transistors, diodes and perhaps the 10μF cap.

Hello Jacques,

Thank your for the reference to the manual and the attached diagran. I thought I should try switching the control panel one more time per your suggestion but that did not fix the problem. Also since I last posted I have replaced the 33 and 45 adjustable pots and the 4 largest wattage resistors on the main board which had a flaky look about them. So what I have now is a turntable that when you push start moves to the record and will set down automatically but no lamps are lit on the control panel for 33 rpm nor does it seem to make a difference if you turn the finger dial in the speed. The 45 lamp will however light if you do not have a record in place and the arm activates the 45 speed as it moves to the end of the platter and returns. The other existing problem is the tone arm will not raise automatically at the end of play in the run out groove. It will however raise if you push the up/down arrow key on the control panel or the forward/reverse key.

I was looking in the manual and on 5-2 one of the faults is "Does the arm rise and out ransport start when pickup gets into the run off groove." I know you have been suggesting the Stand By transistor and diodes but would this be another place to look for the problem or would that not at all solve the no power issue to the lamp in the control panel? I am not sure how to correctly read the parts list to see what the values are for the diodes in the Stand By circuit or for the transistors so would this be something that our friend Martin may have the parts for and I should try to contact him?

John

My 4002 also has the problem with run-off-groove failure. It can be caused by the end stop switch at the end of the spindle, or a faulty 1TR16, which is just an ordinary BC237.

Thanks for that Soren!

John

sorry to bump this thread, but i have a beogram9500, when i go to play any vinyl format the said vinyl plays slow then speeds up to normal speed and stays there.

i was advised by a dealer that i should just let the turntable warm up with the vinyl on the platter spinning at any speed before actually moving the arm into stage.

he told me that the slow start could be to do with under use or dry bearings caused by under use and was best to let it spin for 5 mins and for it to warm up. it does work from time to time. i have just left the problem as its not the end of the world for me.

this might help it may not.