On Sun, 30 Jul 2017 11:54:52 +0100, T i m wrote:

Well, whilst I think they are 'quite clever' I agree that it probably
couldn't test the TOP223Y's.

http://www.eetimes.com/author.asp?se...doc_id=1329331

I have one similar. Yes, they are impressively clever for the money.
By they do not do ICs, only generic components. The only component
that I found will fool it, was a germanium power transistor. The low
Vbe, combined with the low DC gain probably threw it off.

On that ... do you think it might be worth testing (or even just
replacing) the two main caps in case they are getting weak?

Hard to say. There are so many factors that affect the aging of caps.
It does not take many seconds to take them out and test them, though.

I note
they have an extra heat shrink 'skin', probably because they are
pressed up against the tiny heatsink on the TOP223Y's?

Yes, I noticed that, too. Hopefully, the TOP does not get all that
hot.
--
RoRo