I think this subject is on-topic, because vintage computers suffer damage over time due to line-voltage and over-voltage. UPSs can't solve all those problems. But paying attention to the AC power line is important to collectors and users. Shorted tantalum capacitors on DC circuits are a known failure due to both time and over voltage. For example, Heath/Zenith H-89s and H-19s (computer and terminal) expect to operate at 110V AC.T he unregulated side of their 5V DC regulators have capacitors rated at a voltage just below the DC voltage produced - at 110V. When run at 120V or higher, the rated voltage is exceeded and the tantalums "blow". The fix is to replace the caps with higher-voltage devices, and/or reduce AC voltage. That solution won't be found with most UPS. A short-term solution is to use a Variac to reduce AC voltage. Long term, there's step-up/down transformers one can buy for the purpose. Technically-experienced people can make such devices. also: Thank you to Jason Perkins, for his post-link to an article on adjusting a UPS charging voltage. I was aware of this problem but not informed in detail. The article is informative, so thanks! http://www.jjoseph.org/notes/apc_smartups_battery_float_voltage Regards, Herb Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net