Now i have a new problem and i don´t know how to fix it.
First of all i followed all Gromsound tips so i:
1) Replaced the battery with a 1F/5.5V capacitor
2) Changed the 1uF capacitor on the Synch board
and so on....
If i plug in the power cable, the VCR is switching on, all LED´s are in fine condition but only the brake is toggling very fast and klicking several times. If i then press the power on, the brakes are toggling and clicking again - if i try to run forward or backward the drive motors are not spinning. Only the brakes are toggling until i press the stop button. The head drum is not rotating at all and the thread motor is also without any function.
So then i followed the Gromsound tips and checked both boards with the relais under the drive unit. I cleaned the relais with contact spray and checked all the diodes. Everything is well there.
Then i checked the power supply and this is what i found:
If i unplug the M3 connector i have all 12V support voltages. If i plug it back, only +12a is still there.
12b and 12.1b are around 1V only. So i replaced the nearby 330uF capacitors on the backplane,
but the situation is still same

I really need help from this point on

Edit:
MeanwhiIe i changed following identical and good working parts from my 2099 (2024) to this machine but without any success...
1. MOP board --> no change
2. Both relais boards under the drive --> no change
3. CTR board --> no change
4. Power supply --> no change