We're having to reset our office network at least once a day. it locks up and
only a power cycle will get things going again.

We've replaced the router and the DSL modem. No joy. Firmware is up-to-date.
The neighboring office manager says that they are experiencing similar
issues. The building is old and will be bulldozed within a year (60's/70's
vintage wiring).

How can we confirm or eliminate the power as the culprit? Would like to take
steps to filter the mains power rather than measure it (ie, strip chart
recorder) because I'm certain that it's the culprit, and spending a few $$ on
cleaning up the power is $$ well spent, IMHO.

The current power strip powering the network devices -- DSL modem, Ethernet
network router/switch (no wireless) -- has integral surge protection but
nothing more.

All suggestions are welcome.

Sparky