27 Aug
2010
27 Aug
'10
1:07 p.m.
[HP9815 PSU]
The capacitor in question is the 680uF unit on the
output side of the
+15V regulator. The regulator (723) is configured with current
limiting.
I have not analyssed the circuit in detail, but it appears that that +15V
rail (oputput of the 723) supplies the +5V chopper control circuit. It's
not clear what happens if that supply is missing, but since the chopper
transsitors is PNP, I could see it being turned hard on, which would put
30V or so on the 5V line.
No, I am not goign to try this practically.
-tony