Hello, fellow B&O aficionados! And greetings from Stockholm, Sweden!

First post by a longtime lurker. I have just added a beautiful Beogram 4002 (Type 5511) to my small B&O collection. It works just fine after som CLA, thanks to the generous advice offered on this forum. The pickup is an MMC 5000.

The only problem is audible rumble noise (both mechanical, and through the loudspeakers) when the pickup arm motor adjusts the arm position.

If I press START<< with no record on the turntable, the pickup arm will "cycle" in 24 seconds, with the motor buzzing like an electric razor.

The voltages seem to be correct, with 5,5V for >, and 12V for >>.

I feel that I have done the obvious things: I have cleaned and greased the two rods and the long spindle, and put a drop of sewing machine oil on the spindle bearing and the nylon roller that rests on the rear rod. The spindle is parallel with the two rods. I have not replaced the spindle drive belt, but it looks fine and doesn't seem to slip at all. It's wedge shaped, and the sharper edge rests inside the V-shaped grooves on the pinions.

I have also taken the motor apart and cleaned the tiny electrical contacts inside and put a drop or two of oil on the front end of the shaft. The motor is labelled "Maxon DC motor 2023.913-11.111-002".

I have been in contact with Maxon, but they weren't able to suggest a suitable replacement. And according to my local B&O repair shop, spare parts are of course long gone.

Q 1: Any tips on fixing the pickup arm servo motor to be quiet?

Q 2: Has anyone found a suitable replacement for it?

Q 3: Has anyone got any useful information about this motor, so that I can search for a replacement?

My apologies if this has been covered before, but I haven't been able to find any details about this particular problem (apart from others suffering from it!).

Any advice greatly appreciated! /Folke

Hi and welcome to Beoworld ! 

Sorry for asking but I just have to. You did losen the transport safety screws, right ?

Martin

Hello, Martin!

 Yes, I did...  Is this an uncommon problem? I think I have seen it mentioned in the forums.

Hi, I have a servo motor which I think is from a Beogram 4002.

It is marked as maxon DC motor follow by a serial number of which the first number is illegible but reads *023.913 -21.141 -020 swiss made it has two wires leading to a mini plug one is blue and the other is brown.

Let me know if it is the correct one - what I can tell you is it is in perfect working order.

If this isn't the correct motor I have another servo motor somewhere which I will try and find.

Chris.

EDIT

I've a feeling the one above is from a beogram 8000.

I've just found the other one I have and it is marked as 84 000 95 WEISS-MOTOREN D-85 NURENBERG 64 I'm pretty sure this is from a 4002 but I've no idea which version.

Hi there, Chris!

My motor is about 23 mm across and 32 mm long, the axle adding another 8 mm. Maybe yours will fit? I could install a corresponding plug on the PCB (would be very convenient!).

Where are you situated? /EDIT. Yorkshire!

/Folke

Hmm..... the one I have may be from a 4000 or 4004 then as it is not the same as yours, my mistake for which I apologise. It is much larger physically.

However the one I have from a beogram 8000 looks like it will physically fit inside the black plastic casing and is about the same dimensions but whether or not it is electrically compatible I don't know. Perhaps Martin can tell us? if it will do the job then you're welcome to it.

 

Chris.

I'd be very interested! It's the only thing wrong with this beauty (apart from a crack in the lid at one of the hinges - my next repair project!). And it looks so good next to my old Beocord 5000!

Maybe someone can verify that it will actually work? It's a Beogram 4002 Type 5511.

/Folke

PS. The two rear screws aren't missing, I was just removing the motor.

It's a DC servo motor and the system is pretty much self-balanced so I wouldn't be afraid to try.

But are you sure that the problem is the motor ? 

Martin

Thankis for the heads up Martin.

I have sent you a PM (private message) Folke - just click on your inbox at the top right hand corner up the page to access it.

 

Chris.

I'm pretty sure it's the motor...but not 100%. Whenever it adjusts the arm, there's a sound like a low "cough" in the speakers. A bit irritating, actually...! The pickup arm sledge and the arm itself moves freely. No noise at all when I turn the spindle by hand. And the motor makes a lot of grating noise when it fast-forwards the arm. I asked at the local B&O repair shop, and they said that worn out motors was a common problem.

I'm not really an expert with these turntables (that's Martins title) but I'd agree with you that it sounds like the motor is faulty.

Any way, I've got your address and I'll post the motor I have to you next week. Not sure when you'll get it with it being Christmas and all that. I have studied the photo of yours and compared it to the one I have and I'm sure it will fit in the housing but you may need to swap the pullies over or do a bit of jiggling around to get it to line up with the one on the shaft. Hopefully though it will slot straight in.

 

Chris.

Chris, Santa Claus is for real and lives in Yorkshire...

Despite my best efforts, the old motor has seized up almost 100%. I can measure it getting say 9V, but it just wont budge. If I help it rotate, it can go on for a sec. or two.

Chris has been very generous, and I'm looking forward to trying the motor he is sending me. Hopefully, I can find spare parts here in Sweden that he might have som use for!

Update will follow when I have installed Chris' motor. Fingers crossed...

Chris, you have a PM.

If this motor was used together with the board that you send to me
for repair, it's quite understandable. The H-bridge was shorted, causing
full DC to reach the motor at all times, toasting a couple of transistors
as it went along.

Martin

Ouch! I'm keeping my fingers crossed, hoping you can salvage the board.

/Folke

PS. Is it possible that this fault put the motor in "reverse" before the components failed?

Hard to say for sure but certainly not impossible. The board will be fine again, it has been repaired, soak tested and only the trimmers need replacing now.

Martin

Martin, you have a PM

Martin Olsen, if PM doesn't work, please e-mail me

For Chris.

PM seems broken, so I'll post here. Motor's arrived, twirls nicely using a 9 Volt battery, and looks like a drop-in replacement. Update when installed, some more work to be done first. Many thanks!

EDIT/ But now PM seems to work!

Hi Folke,

               thanks - I got your PM and left a reply. There was a problem with the PM system after the move to CS2008 but Keith Saunders has now fixed this - he's a seriously clever guy.

 

Chris.

At last! Thanks to Martin "Dillen's" efforts and support, and Chris "Medogsfat's" generous donation of a replacement pickup arm motor, my BG4002 is up and running! The new motor is dead quiet, the old one sounded like an electric razor and ate transistors for breakfast. But now the turntable is adjusted according to the service manual (thank you, BeoWorld!) and works perfectly. The old, used MMC5000 I found sounds very good, albeit a smidgen bass heavy.

Some minor work remains: I need to polish the acrylic lid, it looks pretty bad, and find some rubber feet. The two front ones are present, but the rear ones are missing. Part No. 3103067, I believe. I'd be very grateful if anyone has a source?

/Folke

Brilliant news!

 

Makes all the effort worthwhile doesn't it? I'm glad I could help in some small way towards getting this lovely deck back into working order.

 

Chris.

Thank's again, Chris!

Another picture, I couldn't resist...they look so good together!

Beautiful - I am genuinely pleased this turned out well. Who would have thought the motor from a Beogram TX (or possibly BG8000 - can't remember the exact source) would work in a 4002? Derfinately one for the memory bank.

Looking at these makes me want a similar system so I may just start with the 4002 I have already and work through ebay. Whether the wife agrees is another matter

Chris.