Alex:
I bought and rebuilt a 6268B,I was told it was working,which it was not.
All of the black diodes were rendered to grey dust but easily replaced. How this happened, I don't have a clue.The only "unique"? part I replaced was a little transformer that I had to find a substitute for .
I think it was a "pulse" transformer. About the size of a DIP relay. It is not a snap to align this thing but I did it, so it cannot be that hard. All transformers "Hum" they are musical. I cannot hear the hum over the fan noise, which is not inconsequential. Run mine at 28 Volts for a GRC 106 military radio mostly.
I bought the PS because I was sick and tired of dealing with birdies on SMPS PS. This thing has no birdies. (Maybe the humming scares them?)
A really nice PS.
Wally KC9INK