Hi Jens

It sounds like it isn't coils then, which is good news.  Time to look elsewhere...  😮

Good luck!

hi ray!

yes, i was quite happy seeing the platter turning again🙂.

changing the transistor for the cpu reset didn´t change anything, perhaps i´ll have a closer look to the brake-circuit,as it feels abit like the platter wants to spinn and brake at the same time or alternating in a certain frequency.

greetings!

jens

jens m wrote:

yes, i was quite happy seeing the platter turning again🙂.

I bet!

jens m wrote:

changing the transistor for the cpu reset didn´t change anything, perhaps i´ll have a closer look to the brake-circuit,as it feels abit like the platter wants to spinn and brake at the same time or alternating in a certain frequency.

That would explain a lot.  I wonder if it is easy to disable the brake circuit to test?

It won't run steady or brake properly WITHOUT the heavy platter.
It is quite normal to see it keep spinning, sometimes even backwards when power is
applied if no platter is mounted.

Since securing a non-rotating platter is part of the processor startup sequence, you can't judge anything
without the platter, it won't get any further in its program before the sensor reports no platter rotation.

They are wonderful machines but not as easy to service as it may seem at first glance.

Martin

hi martin!

i´ll try with the upper platter tomorrow, perhaps i´m lucky and it will run smooth then, but this afternoon the fuse  went off again, so i think, there´s still a problem...

i ran out of fuses and have to get another pack tomorrow.

thanks for your input!

have a nice evening!

jens

I hadn't thought about it, but yes the platter must be on or they go a bit mad.  My non B&O induction turntable used to go into warp speed...  😁

beam me up, scotty!😕

latest news:

with the sub- and upper platter the beogram spins as soon it is connected to the mains, when play is pressed the tonearm moves to the startpoint and after a bit longer than usually the platter reaches stable 33.33rpm and then, when the arm proceeds further - looking for some vinyl - stable 45rpm.

when i press stop, the arm goes back and the breakcircuit stops the platter until it stands still, but as soon as the break circuit did its work the platter starts spinning slowly again.

i was wondering, if the bipolar cap inside the housing of the ttransformer could cause the trouble and only could measure, that it´s not shorted and then i had a smaller bipolar by the hand and put it in parallel, just to check, if it´s lacking capacity, but nothing changed. it´s rather hard to get hold of a 39μF bipolar cap...

next thing i´ll do is check the circuit around the coils.....

greetings from bavaria!

jens

Seems to be a floating control signal.
Resolder all plugs and connectors.
Also the row of solders where the ribbon cable from the processor goes to the main board and check that no
leads in this cable has broken.

When you replaced C27, did you remember to introduce the ground connection
as shown in the cap kit inlay sheet ?

Martin

hi martin!

i haven´t had your cap kit, only your tachodisc and took caps from the shop around my corner.

i replaced the 47μF cap inside the metal shielding of the cpu, according to the service manual it´s C28; minus is connected to ground/to the metal case, but i think my connection is pretty much the way it was before, so if you refer to a chnge in how the cap should be connected, i probably havent done it.... i didn´t touch C27 4,7nF though.

i already resoldered the connectors, but i will check one more time to make sure, and will check the ribbon cable coming from the cpu.

thanks alot for your help!

jens