I'm sure the reason for the instability must be related to the 25 volt
line going out of regulation under load but I'm at a lose to
understand why.
I haven't looked at the schematics, so I'm shooting from the hip here. My
5328A started to smell of stale cat's pee - it was otherwise working though.
Turned out that the two screw-mounted reservoir caps at the rear of the
board were on their last legs - not leaking as such, but clearly not
healthy. Just replaced them with modern components, and all was OK
thereafter - the cat was banished.
Craig
