I did read that blog 🙄 before.....not much point trying that as my platter already spins anticlockwise in Standby 😕

are you implying that 1TR31 somehow may has its base connected to ground ?!?

again i had a look at P4-1,2 and 5:

P4-1 = 13.4VAC, supplied from P7-5and remains the same in StBy/Play

P4-2 = 26VAC, supplied from P7-12 / 4C1 and remsins the same in StBy/Play, which is also at 1D40 cathode,

while the anode side of D40=32VAC, influenced from P7-11 via TR31 ?!?

P4-5 = 0.040VAC in StBy

ALF

I am implying that the symptoms you have match what Beolover was doing intentionally. Beogram is in standby mode and the platter drives in reverse. That can occur due to the brake circuit. It could also occur with a microcomputer problem if the problem was that the microcomputer had the Beogram in standby mode and was sending a brake circuit command at the same time. I believe you checked that and that is not the case. So in order for the Beogram to operate in reverse I think the problem has to exist in that brake circuit. With the Beogram in standby start checking at the motor and see what voltages are there. Trace back from there to what is causing the problem. Have you gone through the transformer connections and the 39uF capacitor there?

A quick check of the microcomputer's role in the problem would be to disconnect the 2IC1 pin 37 connection at 1R108. That is where the brake stop command comes from. If the Beogram platter still drives in reverse then that will eliminate the microcomputer having a role in the problem.

Here is what happened after disconnecting the uP from the brake circuit (disconnecting 1R108):

In StBy mode after connecting deck to mains platter does not spin anti-colockwise, however deck does not power-off (servo light bulb still on)

and the platter motor still shows some very gentle stuttering clockwise !

after reconnecting R108 to the brake circuit checking voltage at P6-5:

in StBy mode P6-5 = 0.72V

in Play mode (after hand-brake, platter spinning clockwise)  P6-5 = 4.95V.... back to STOP/StBy voltage drops to 0.72V

can we still exclude the uP from the problem ???

from memory: didn’t you check/question the voltages (transformer) at P7 in one of your posts or am I wrong here ?

I replaced 4C1 (39uF, 55V) as it showed 57uF !! with a 47uF 100V cap, which actually shows 42uF, close enough.

the original value is nowhere to be found 😕

ALF

If the emitter of TR33 gets AC current from P7-11 I should measure VAC at that point ?!

the same would then apply to its base and collector.....if so, how can I get basically the same readings at E, B and C ?

or am I sitting on my brain ?

ALF

ALF wrote:

Here is what happened after disconnecting the uP from the brake circuit (disconnecting 1R108):

In StBy mode after connecting deck to mains platter does not spin anti-colockwise, however deck does not power-off (servo light bulb still on)

and the platter motor still shows some very gentle stuttering clockwise !

after reconnecting R108 to the brake circuit checking voltage at P6-5:

in StBy mode P6-5 = 0.72V

in Play mode (after hand-brake, platter spinning clockwise)  P6-5 = 4.95V.... back to STOP/StBy voltage drops to 0.72V

can we still exclude the uP from the problem ???

from memory: didn’t you check/question the voltages (transformer) at P7 in one of your posts or am I wrong here ?

I replaced 4C1 (39uF, 55V) as it showed 57uF !! with a 47uF 100V cap, which actually shows 42uF, close enough.

the original value is nowhere to be found 😕

ALF

Interesting results. The voltage measurements here would be better if they were with an oscilloscope so we could see the phase of the AC voltages at P4-1 and P4-2. I am curious to look at one of my Beogram 800x units the chance I get (maybe in September).  Several years ago I tried making some measurements of the Beogram 8002 transformer outputs but that was on my first Beogram 800x restoration and the results aren't useful here. Your 4C1 capacitor should be okay except I would have tried for a DC voltage rating closer to 55V.  You made sure to use a non-polar capacitor, right?

I will try to replicate those with the scope....and YES, 4C1  is a non-polar cap where I tried to find a lower DC voltage rating !

lets see what the scope provides us with ?

ALF

The signals at P4-1 and P4-2 in StBy/Stop mode are in phase !

I tried to upload the scope picture but won’t allow as it does not have the right extension.....

i will try the digi camera and hope to upload this way....

ALF

Hi ALF,

The current will under go the phase change not the voltage so unless you have a current probe for your oscilloscope you won't be able to measure the phase change.

Regards

Lonnie

well, I do not have current probes for the scope

so this lousy shot with the digi camera shows the VAC signals  in STBY/STOP mode at

P4-1 and P4-2 respectively: