Hi Radiojoe, and Dan3460 -
My TDS-420a also has the identical Power One PS as in Dan3460's picture, with the 6pin opto in one corner and two big input caps on the other, and two vertical heat sinks between the sets of coils... In my set, with the board no longer shorting to ground, still nothing shows up on the CRT, the ten front panel leds light and the set hangs, CPU board shows ".8" ...
When first taking the cover off, upon inspection, I noticed that one of the plugin boards, the one closest to the PS (centronics/serial card) was installed with the back of the card shorting to a metal brace running front to rear in the chassis - due to faulty insertion of the plastic retaining clips for those plugin boards.
At this time, I have yet to pull out the PS. Can someone post the ratings (uF and voltage) of those five output caps, so I can look and see if I have any replacements for them at the moment? Thanks,
Its now almost ten days later, if you have this supply and it has never been removed... There is a "hidden" torx #10 screw besides the four clips. Need to remove the fan as this screw Is behind the transformer and is not easy to get to. I struggled for an hour and even broke a screwdriver trying to lift the board out while this central retaining screw was still in place. Once the screw is out, its simple, four clips and it just lifts up, then go towards the rear, turn outward towards you and its out. It seems there are four voltages 5.1 at 15 amps, +15 at 3.5 amps , 6.4 at 5.5 amps, and -15 at .75 amps.
Steven