Tek tds420 psu failure

[boddax]

Hi , psu (Power Supply Inc ,model PS-1690) of my scope tds420 is faulty since no schematic and beginner in electronics i am here asking help. have desoldered the two mosfet they seems ok ,have some voltages on high voltage side but on regulation side (lm339 nothing) mesuring with no load
and dont know how to start withoput stby button.
where from i start to measure to reach the problem?

primary mosfet :MJF16006A (seems ok)
secondary mosfet:BUK454 (seems ok)
custom chip tek 3 wires (i have 137Vdc on each wire)

here the pictures

[kc8adu]

Re: Tek tds420 psu failure

last one of those i saw had the small caps dried out.replace them first.