Beomaster 6000 volume motor gear

This little Beomaster 6000 was given to me in exchange for $1. Many of the little issues are now sorted except the volume control motor is not working. One of the plastic gears had some of its teeth stripped out. Any good suggestions for fixing this soft plastic gear?

The little clear gear on the left has is the one with the inner teeth rounded out. This shot is from the bottom of the motor where the belt attaches

Here is from the top cap, the top one of the copper tabs was broken off and inside the motor loose causing it to be jammed.

So my guess is that someone tried to turn the belt, which turned the plastic gears,

against the resistance of the frozen motor and rounded some teeth on the plastic cog.

I'm thinking about putting some epoxy in the rounded out spot where the teeth had been and then cutting notches into it but I think epoxy could be too soft.

Any good suggestions???

As the perspex and the Nylamid gear are identical, I would try to get one 3D printed

Thanks Søren, I had never heard of Perspex or Nylamid but researching gears made by them I think I found them from China. I guess we will know in a month or so.

Also, how were you able to identify them? I couldn't find anything in the service manual. Is there a reason the two types were used and how interchangeable are the types of material?

3D printing is a new world I know nothing about but apparently I will need to learn how to use or utilize.

Perspex is also known as plexiglas is mostly used by B&O for covers like on the BGs, why someone with mechanical engineering background would use it to make gears makes me wonder, perspex is brittle and hard, Polyamide (Nylamid) is also known as nylon, has much better mechanical values for making gears and bushings and the like for engineering. The 2 white gears in your pic are made from polyamide

3D printing is fabricating parts with plastics, from a scanning of an original part, or from a Cad drawing, if you search you will find a company or business near your location, that do 3D printing.

Back at this poor Beomaster 6000. With the gears from a non-working motor and new belt from Martin the volume control works!

Except it doesn't. All appeared to be working well except it was randomly resetting the volume to the the preset. Then it would randomly start turning the volume down and then the motor would not stop when it hit 0. Adjusted the preset slider and the volume buttons and then it would stop its endless futile pursuit of negative volume.

Happened again after 20minutes. Service position again, this is what I see

IC5 is sitting in a burnt hole on PCB 6 for the motor control. I don't know if this is new, I don't smell cooked board but I'm surprised I didn't see it all the other times I've had this in the service position.

What would cause this to burn?

When I first got this Beomaster I had to repair a couple wire connectors, I can't remember which at this time, could this have been burnt out from that? It would explain why the gears were stripped out in the motor if it was just left to run endless as it tried to find infinite 0.

Looks like someone else has addressed this burned motor control board before me

Pulled out the board to inspect what kind of damage there was and I found someone had already tried patching. I guess maybe this is why I was able to buy this BM6000 for a dollar.

Motor and belt sure work nice, though. If you happen to have a parts Beomaster 6000 laying around, I am looking to buy this PCB 6 now.

Email me...

Martin

Well, this journey is almost complete.

With a volume control board from Martin installed and with new trimmers it was acting better but would still without warning drop the volume to the preset and have other random volume changes and continuous motor running behavior. Another beoworlder messaged me offering help and made a comment that it is probably something really simple.

Following the service manual on adjusting the volume control settings wasn't working to stop the run away motor behaviors. This week I attacked it again and kept thinking it must be something really simple as was suggested and so I kept to simple diagnostics, rechecking wires, connections, solderjoints, nothing. Replaced the capacitors on the tone control board PCB3 and very detailed cleaned the preset (and other) slide control switches. BINGO!

I've been playing it for 6 hours straight now and no sudden changes or run away volume motor. Thanks for all your help everyone. This only took me 10months to solve all the problems. Pictures to follow.