Beogram 4000 servo belt question

[PeteV]

Hello,

I have an Beogram 4000. Its serial number indicates that it is an early model, i.e. the one with the round carriage servo belt, and indeed the belt currently installed has a round cross section. This can be seen in the picure below. It is also obvious that the belt is very loose, most probably because it is the incorrect belt(?). Rather surprisingly, the carriage transport works well, even with this floppy belt.

B&O’s service notes indicate that this belt should be replaced with the new triangular belt, together with new pulleys. However, while the belt and new aluminium carriage shaft pulleys are available from DKSoundparts, the same cannot be said for the carriage motor pulley.

However, looking at the pulleys currently on the turntable, they both have distinctly triangular grooves, which makes me think the pulleys have already been replaced at some stage. This can be seen in the photo. The question I have, can anyone tell me whether these pulleys are for the new triangular belt, or are they still the originals? If not, what is the difference between the original and new pulleys?

Given the age of the pulleys, and the reputation the carriage pulley has for disintegrating, I would like to replace them. If I do need to replace the motor pulley, does anyone know of a source for these?

Many thanks

Peter

 

[Mark-sf]

There is no need to replace the motor pulley if it is not cracked or deformed.

[PeteV]

Thanks for that. Normally I would agree, but the reason for the question is that the service manual specifically says that both pulleys should be replaced when fitting the new triangular belt to early model BGs. While I clearly have a round section belt, the pulleys look like they are the right shape for a triangular section belt.

[hcraig244]

I have been inside several BG4000 over the past few years and not seen a carriage motor with a pulley wheel with a different profile to that which yours has, that doesn’t mean there are none out there of course. Regarding the belt I have had one with a round profile belt that worked fine despite being somewhat floppy, I suspect it started life as a O ring and not a drive belt….I replaced it with a belt from Dillen and adjusted the tension accordingly. The Service Manuals B&O supplied are very detailed and for the most part accurate….but im sure im not alone when it comes to stumbling over the occasional inconsistency therin……..buy a replacement alloy pulley for the drive shaft and a new belt and you will be fine, yours does look perfectly fine by the way……I should replace mine also, just havent got around to it yet ;¬)

Craig

• This reply was modified 4 days, 4 hours ago by hcraig244.

[PeteV]

1. Thanks for the comprehensive reply, Craig. I will probably do as you suggest.

[Mark-sf]

Across the many 40xx turntables I have serviced, I have never replaced the pulley of a working motor. You’ll be fine with the proper belt and shaft pulley.

[PeteV]

Thanks, Mark.

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