Soren,

I did some reading on this - looks very interesting.

I have no experience in the plastics area, and I would be very confused trying to choose between all those Nylamid products!

Definitely keep me in mind, and if you want me to test your creations ❓, feel free!

Menahem

Solved.

The bottom line is real simple - when you've got nothing to lose, the world is full of options.

So, I decided to ream out the centers of the brass bearings.

As Martin proposed, the bearing centers were discoloured, most likely due to the smearing.

The motor axle diameter is 2.8mm thick, so I took a drill bit of 2.5mm, and wrapped 1000-grade waterpaper around it, and very gently threaded it in and out, rotating at I go. Took a good few patient minutes.

Then I changed to 2000-grade, and did the same thing.

Cleaned out the detritus with alcohol, and tested for slipperiness over the shaft.

When it was supper slippery, but with no lateral sloppiness, I oiled and reassembled.

The motor is PERFECT!

With these machines, there is ALWAYS something new to learn!

Here is the incriminating evidence!

Spins like a bat out of hell - superb! And the long spindown is exquisite!

Does anyone know the original correct diameter of the Rubber Idler wheel, when the rubber was soft, and hadn't contracted yet?

I had to trim the hardened rubber off the edge (now 55.8mm) and it now spins at almost 45, with 33 selected (30 or 25 on the dial).

I have 2 other spares here, measuring 56mm and 56.8mm, but they're also both fast.

My intention is to send them to Terry Witt anyway for new rubber.

OK, so you're reading this and saying to yourselves - what a dumbass 😁 - he still hasn't fixed the motor - it's rotating 20% too slow. In order to get it to rotate at 33rpm, he has to put the selector at 45......

Well, I started doing the math - I hadn't done this math since I was in university 40 years ago. Wheel ratios, and RPM's etc.

It worked out that in order to rotate the platter at 33rpm, the Rubber Idler diameter needs to be 71mm!!!!!

No way. The maximum idler diameter which would physically fit in the BG is 59mm.

So, either I made a royal screw-up with the bearings, or there was something else.

During the calculations, I had assumed that the Brass Pulley diameter is fixed (with a 3% variation), So I went back to the calculations, to solve for a pulley diameter variable which would suit the existing Idler diameter of between 56-59mm.

And I came up with a pulley diameter of 5.6mm.

Then I looked at my own BG1203, which works flawlessly (no surprises there), and I had a double-take. My BG1203 pulley LOOKS fatter than the BG3000 pulley. I pulled out my calipers and measured. Click on the picture to open it fully, and see all the Results.

The BG3000 pulley is THINNER. It probably comes from a country with 60Hz  electricity.

My BG1203 was bought in Israel (a 50Hz country) - and has a diameter of 5.6mm on the 33rpm section!

Can anyone in the Americas confirm that their pulley matches the thinner of the 2 pictured below?

And if anyone wants to get rid of a fatter 50Hz pulley (swap for other parts), most appreciative.

Soren, I remember that you made up your own 60Hz pulley - were these dimensions close to what you calculated?

Menahem

There are different sizes, not necessarily related to the mains frequency.
These are both for 50Hz Beograms but with slightly different motors:

Login to view image

Martin

Different motors, eh?

I went back and checked the 2 motors, and yes, they are different.

Now, when I match the motor with its appropriate pulley, the speed is perfect.

I never noticed this before - It appears that this is the first unit I've seen with the thin pulley and wide motor. Perhaps it was a very early production combination.

Anyway, I still like the idea of mismatching the pulley and motor to get 60Hz compatibility!

This is the part which was allegedly replaced in my 1203... not 100% convinced though.

It's still running nicely... cleaned it all up, takes a song or two to get up to speed but can't complain. Have it linked to some Kef 101's that my dad once owned and the sound is amazing.

Still trying to get the 1202 back working... will part out if I cant...

Menahem Yachad wrote:

Soren, I remember that you made up your own 60Hz pulley - were these dimensions close to what you calculated?

I didnt change the motor pulley, but made a new poliamide belt pulley instead of the steel belt pulley. The new belt pulley is 20 % smaller than the old steel pulley.

the wheel is overall diameter 28,5 Mm. the original is 35.4 Mm, so a little oversize, its easier to machine down if too big

And here my thread about it

http://archivedforum2.beoworld.org/forums/p/1666/14226.aspx#14226

Yachmed

One year later, is the beogram till working perfect ?

I have 3 piece of 1200 with this problem , exactly as dillen described, just cleaning and oiling the motor works only for a couple of days.

DIllen,l  volontair if you have some new pieces to try.

Christian