Dead 120 VAC circuit - troubleshoot?

Your checkout readings from the Tenma model are pretty good. It's definitely annoying when DMMs hunt for a reading. Tenma was a generic/clone product company that's turned into a fairly widely recognized brand name. The no-name brands that sell in about the $6 and up range are what quite a few sellers are offering lately. The term digital doesn't assure accuracy, and doesn't much matter if the device is a DMM or a bathroom scale.

A good practice is to take test readings of known voltages before circuit testing begins. When weird/unexpected readings are encountered, the user needs to determine why, to be able to proceed safely.

Simpson, Triplett, Weston have all made durable, reliable analog meters (and most still do). Older analog or digital meters are great if you're the original owner, that way you could be sure that they haven't been OV'd or abused. I still have a working one that was new in about '73. Aged meters (decades) shouldn't be expected to be as accurate as when they were manufactured because component values will drift with age, but their durability is their real value (and they can often be recalibrated or repaired to their original accuracy). For home/shop wiring voltages, an error of a few volts isn't very critical.

Beckman made some of the highest quality DMMs, although they're produced under Wavetek now (and look like a design school project for a TV/VCR/? all-in-one all purpose remote control). The Beckman Industrial 100-4000 series were extremely well built. Not many handheld DMMs had a 1000-1500VAC range, which is important for 460+ 3-phase AC (because the phase-phase peaks exceed the 750VAC maximum input of meters with a 750AC max. range). Old Beckman DMMs can be problematic.. the switches may have become oxidized, or the LCD holders may not be as tight as neccessary to maintain consistently clear readings (missing display segments).

WB ................

house/building