Bosch VM 60/R-T

[acakololec]

Good day
Respect to all.
I have a problem with the power supply from the title. I located the fault by elimination method and found that the problem is in the servo board (bosch 052303-4047), attached picture.
I need help, how can I test the board without power, or if someone can direct me where to look for a fault. I should note that I replaced all the electrolytic capacitors, checked all the diodes.

Thank you

 

[DeadMahoDude]

Darlington drive transistors get DC-voltage over DC-link busbar on top.
3Phase rectifier is inside the power supply unit.
Power supply unit also makes high frequency voltage, for those 3 transformers, back when I repaired my ASM25, I used Tek FG501, audio amplifier and a large 24V/220V transformer in reverse, to supply these transformers with HF voltage. Don't know the specs exactly, but you should be able to measure that inside your machine.

Usually transistor modules fry in these units, DC-link capacitors were also degraded, on my machine.
Be aware of fake chinesium transistors on ebay and be sure to fix all of them, one bad transistor and you will likely end up with more toasted transistors and perhaps kill a servo (toasted windings).