13 Feb
2022
13 Feb
'22
11:35 a.m.
On Sun, 6 Feb 2022, Peter Coghlan via cctalk wrote:
It seems like great progress! Yes, those etched markings are sometimes
hard to decipher, requiring looking at the correct angle with light coming
NB Mouser has
the MAP80-4000G in stock actually, so if all else fails and
you are determined to get the IGS running, you can pick a brand new one:
<https://www.mouser.co.uk/ProductDetail/784-MAP80-4000G>.
Thanks again Maciej.
I've bit the bullet and unsoldered most of the electrolytic capacitors and
other components that seem to be in trouble. When I got the chopper
transistor out, I found that if I hold it at exactly the right angle to
the light, I can see that there are faint markings on it after all and it
turns out to be an IRFPE50 HEXFET. I was wrong about the cracked RIFAs
not being mains filters too, they are actually across L-E and N-E and
they seem to have between a few hundred kOhms and a few MOhms leakage too.
The driver transistor looks like it might be ok. from the right direction too and/or techniques used to
take fingerprints
at a crime scene. With these details known you may be able to
actually
get this sorted just by yourself. Good luck again!
Maciej