[didier]

Hi everyone,

I found a Beogram 2000 that fits perfetly with my Beosystem 2000 – love the look!

But functionally it is less than stellar. The motor is making a squeaking and grinding noise (and the sound is distorted, but that’s probably the cartridge that’s shot.)

Does anyone know the compatibility of the motors in that range? I see they share the same service manual as the 1800 and the 5000 – is it safe to assume they are interchangeable?

 

[Dillen]

Have you checked the motor suspension?
There is a good chance the motor pulley is rubbing on the metal bracket due to failing suspensions.
Read here:

Motor suspension rubber bushing grommet set f. several Beogram Beocenter models

Martin

[didier]

Thanks Martin,

I will investigate this – and won’t miss to add these in my next order!

 

[didier]

You were completely right about the rubber suspensions, on eof them was completely squished, while the others were dried up.

Although, even at no load the bad noise continues, here is a video:

https://www.youtube.com/watch?v=QYMYdzi4Bj8

It is my first Beogram, but I think this is not normal…

[Dillen]

Many motors will run a bit noisy unloaded.
Have you tried with a belt fitted?

Martin

[didier]

I did a temporary fix to get proper clearance for the belt:

https://youtu.be/j-3bKzEZ8TA

Right now the belt is not touching anything but the noise is still there…

[AdamS]

I’m afraid that’s the classic noise of a common fault!

The magnetic ring for the FG servo is just above the commutator and when the plastic “tyre” that holds it in place cracks, the loose end gets mixed up with the brushes and makes a noise. Normally just removing the offending loose piece is all you have to do, the ring seems to stay in place by itself.

To do this you have to remove the bottom of the motor, unsolder the PCB and then take off the brush plate. It is much easier to put it back together if you take the pulley off first, then you can insert the rotor into the brush plate before sliding the complete assembly into the stator. Be sure not to lose any of the spacers and washers on the motor shaft, their positions are important. A tiny spot of oil on the two bearings is also a good idea while it is in pieces.

If that sounds all too scary, though, another motor from a turntable of the same range will fit and do the job. Don;t throw the old motor away, though – pass it onto someone for fixing!

[didier]

For future reference, the motor in question is a Matsushita mmx-4h2rpb, it seems to have been fitted on:

• Beogram 1800
• Beogram 2000
• Beogram 5000 and 5005
• Beogram 7000
• Beogram RX2
• Probably a few others…

[didier]

Thank you for sharing!

I got to the PCB in the motor… I’m guessing I can’t go deeper without unsoldering as you said. Do I need to do all the solder points?

 

[Mark-sf]

You only need to desolder the two larger pads at 12 and 6 o’clock.

[didier]

I appreciate the answer Mark, I am waiting for a new solder station and will update

[didier]

Okayyy… I removed the broken plastic piece and it now runs smooth and quietly!

But… It runs backward ?

I disassembled again and looking at the way th parts fit into each other, I don’t see how I could have reversed the polarity by mistake.

[chartz]

Bonjour Didier,

The magnet polarities are reversed, not electric polarities.

Always put marks before disassembly, to avoid that kind of mistake.

Classic!

[AdamS]

Whoops – yes, sorry I should have said that.

And don’t worry – we’ve all done it!

[didier]

Bonjour de Montréal, chartz!

This is the insides of the motor… you can see the cracked plastic I removed at the top, they were originally on the side of the magnetic ring. I didn’t have to disassemble further

Now I don’t see how I could have reversed the magnet polarities since the shaft can only go back one side (so that the brushes can touch the commutator.)

Similarly the brush plate can only be reassembled back one way since the square hole accommodates the chip on the board…

Or maybe I misunderstood something

[Author]

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