On Fri, 21 May 2021 10:48:32 +0100, T i m wrote:

snip

Any change in performance with ANY of these part subs?

I'm still waiting for the small caps (might be here today, whilst I
have some stock of caps, I never seem to have the spec I want), and I
intend, assuming this wouldn't risk any other stuff, to replace the
two caps, then opto, voltage reg then switcher in that order (as I
believe that was the order you mentioned the likely cause)?

Update: The caps arrived this morning so I re-fitted the txfmr, the
switcher and rectifier, then fitted the new caps and tested it. DMM
shows around 10V on the DC range (as before off load) but it's jumping
about a lot and about .5V on AC.

I then replaced the opto and then the voltage reg with the output
looking the same each time (allowing for the voltage on the main caps
to bleed down each time etc).

So are we now looking at the switcher itself and / or is there
anything else I can check in the meantime please?

Cheers, T i m