My electrical knowledge is fairly limited, so I'm hoping someone here
can shed some light on this or correct any mistaken assumptions on my
part. Our house is 60+ years old, previous owner worked for a
homebuilder and did a lot of the improvements to the house himself.
We've been here almost 7 years, and have had relatively few problems
outside of the usual age-related ones.

The room being used for an office has two computers, two monitors,
flatbed scanner, inkjet printer, router, cable modem, external drive,
two powered subwoofers, and a small desk lamp. The computers each have
their own UPS (APC Back-UPS ES 650 and 500). Within the past few days,
the UPSes have started clicking several times a day. These UPSes beep
several times when switching over to battery power, and they haven't
done that more than once or twice, but the clicking would seem to
indicate a voltage drop significant enough to cause them to start to
switch over. This only lasts about a second or less, and I've observed
the lights in the room flickering just a bit at the same time. I've also
observed lights flickering slightly in other rooms, so it's not limited
to just the office.

So, I decided I'd better get someone out here to look at the panel. I
have a main panel (125A) and a subpanel (75A), and they are both of the
notorious FPE Stab-Lok kind, the evils of which I just learned about
after doing a bit of Googling. The guy that I hired examined both panels
and tightened down all the connections, and said everything looked OK as
far as he could tell, but recommended that when I'm ready to upgrade I
should install a newer panel with more capacity (the breaker on the
subpanel that covers the office also covers two halogen wall-mounted
lights in the hallway, the master bedroom, the guest bedroom, and the
living room. The guest bedroom and the living room are very infrequently
used.). He also reanchored the utility drop where it splits into three
main cables just upstream of the meter (hope I'm using the correct
terminology here), as the cables had come loose from the "anchor"
mounted on the house and were "pulling" on the connectors.

I thought this must've fixed the problem, as it was not reproducible
while he was here, but a couple hours after he left, the UPSes started
clicking again. I'm concerned that this will ultimately cause damage to
the computers or the UPSes, and am wondering whether I need to get a
second opinion from another electrician, or whether I should call the
utility and ask them to put a line monitor just upstream of the meter to
see if it's an issue with their equipment. I'm concerned about the
panels after reading about FPE's failure rates, but unless I get a
professional opinion that they're unsafe and should be replaced
immediately, I'd prefer to defer doing so until a couple of other
expensive improvement projects are completed.

Comments or recommendations?

Thanks in advance,

Dave