Happy new year to everyone!
A new year and another project to finish – the new power supply. Whilst I have already two machines running with the new power supply I figured out some interferences with the service manual and real life. The service manual does not differentiate between analog- and digital-ground. As a result I have a minor buzzing sound, almost unnoticeable, but exiting. Although these two machines are working, a third one failed and, as soon as the decoder panel gets connected, audio output mutes.
It was also not possible to pursue the relays to switch on the power for the CD-Player. Well, I had to do some reverse engineering to figure out that the service manual misses some important information. I also decided to use optocouplers to separate the different grounds. I think this is the best solution. Any other idea is highly welcome.
On the other hand, the two running power supplies seem to be reliable and stay extremely cool, compared to the original.
I have done some temporary changes to the not working machine with the new power supply and adopted the new circuit in KiCAD. A new PCB got already ordered… let’s wait and hope that Release E would be the last one. My bank account would be very pleased…
