On 15 Mar 2016, Cursitor Doom wrote
(in article ):
Wrong! The question *solely* concerns the *old* unit that failed.
Welcome to USENET. There is no €śon-topic€ť!
Under conformal coating it is difficult to examine anything.
Check any large transistors.
Id also look for broken solder joints on the large devices (caps,
transformer, choke, I/O connectors). Also look closely at the cap €śnorth€ť
of the big choke. Has it leaked and damaged a trace?
Also check ESR of all the electro caps.
And as was mentioned earlier, be sure the xtal is working.
A success story:
https://www.youtube.com/watch?v=uLIHxqqrY_M
Good luck!