[sdiy] Problem with 723 PSU

[jorgen.bergfors at idg.se]

Thanks a lot, all of you who have offered advice on this problem!
I looked at it some more last night.
It seems the theory with the long cable causing the problems was a false assumtion.
I was fooled by the fact that when I connected the transformer direcly, I also disconnected the other PSU unit.
What most likely causes the problem is that I run two units from the same transformer winding.
This works fine for the positive regulator, but evidently not for the negative. This isn't really surprising, considering how the regulator is designed (positive regulator connected "backwards").
I'm almost certain that if I get another small transformer to run one of the two regulators used for -15V, everything will be fine.
Connecting resitsors, caps, ferrite beads etc to the AC inputs did not help, by the way.

/Jorgen