BeoGram

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

Step1 — Wed, 30 Mar 2011 12:20:49 GMT

One more thing to add to Graham above is that if the bearing was dried up, the last thing you would want to be doing would be to run the player at all! I would let a drop of mineral oil sit on the bearing and let it soak in for a bit to be on the safe side!

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

joeyboygolf — Wed, 30 Mar 2011 11:26:34 GMT

jahur:

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.

Fit a new drive belt. You can't really tell anything until you do this.

I have sold very many B&O tangential decks and I have never known one to need "warming up". Suggest that is dealer bullsh1t.

Order part number 2732062 from another B&O dealer or contact member "Dillen" who can also supply.

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

jahur — Wed, 30 Mar 2011 09:51:44 GMT

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.

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

jfrancis — Sat, 05 Mar 2011 00:44:41 GMT

Thanks for that Soren!

John

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

Søren Hammer — Thu, 03 Mar 2011 09:00:26 GMT

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.

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

jfrancis — Wed, 02 Mar 2011 18:40:39 GMT

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

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

chartz — Wed, 02 Mar 2011 02:51:59 GMT

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.

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

Søren Mexico — Tue, 01 Mar 2011 18:13:49 GMT

jfrancis:

"my kingdom for a horse."

John

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

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

jfrancis — Tue, 01 Mar 2011 17:15:45 GMT

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

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

chartz — Tue, 01 Mar 2011 03:13:50 GMT

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...

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

jfrancis — Tue, 01 Mar 2011 03:01:38 GMT

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

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

jfrancis — Mon, 28 Feb 2011 20:16:48 GMT

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

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

Telecine — Mon, 28 Feb 2011 19:06:17 GMT

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.

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

chartz — Mon, 28 Feb 2011 10:18:08 GMT

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!

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

Telecine — Mon, 28 Feb 2011 07:49:45 GMT

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.