I recently acquired a broken 53131A frequency counter with the intention of repairing. Unfortunately the seller didn't say but a repair had been attempted previously on the power supply module. Unfortunately this means there are components missing and other components that have been replaced but I don't think the replacements are correct.
Is it possible to get schematics for the power supply? The supply in my unit is a Delta SMP-43DL.
It looks quite different from all the teardowns I have seen online although those were Agilent branded and this unit is HP.
In particular I am looking for the type of transistor Q2 (main switcher) capacitance values for the main bulk (C2, C4 and C3, C1) caps (they have been replaced with 47uF 250V units). Finally ZD1 is missing.