[JohnCT]

We did tons of those, and success depended on two things: changing all the bad parts at once because leaving one bad part would cause immediate destruction of the others, and use Sony only parts.

When these came in, we'd change the SG613 horiz output, the 2SC867A LV reg, and the damper diode whose number escapes me right now, but I remember the damper was a large metal can type but the Sony replacement was a smaller epoxy diode.

If you just change the SG without changing the 867A reg, the SG would fail immediately. If you just changed the 867A without the SG, the 867A would fail immediately. Same with the damper. Change the Holy Trinity of Sony parts using OEM and there shouldn't be a problem. It's been a long time but there might have also been a low value resistor that burned up in the power supply. Been over 30 years since I've last seen one..

It was also important to check the sockets of the output and regulator to make sure they were tight. I used to keep a sharpened awl to make sure they were (helpful with some RCAs like the 132 chassis). Also, go over the whole HV board and make sure there're no bad solder connections, or wayward conductive glue, and look for physically damaged film caps. I don't remember if there was a coupling electrolytic between the horiz osc and the horiz output, but if there is, change that as well.

I honestly can't recall any other problem causing those parts to fail. The flybacks were excellent in those. But, do NOT run these on a variac. I'm not sure of the exact chassis but some of the early Sonys would destroy themselves below something like 90VAC or so.

John