Heathkit model V-7A tube voltmeter acting up. Help?

[Sealtest]

Hey all, I have an interesting issue with a little Heathkit V-7A bench meter. Yesterday I got to clean out a long closed TV repair shop and this was one of the pieces of gear I got.

Initial testing showed life, but the Ohms setting does not read as it should. The meter jumps around. I can touch just the positive lead with my finger and the meter will show a reading. The RX selector switch does nothing as well. I figure this needs restoring of sorts but I would like to avoid replacing every single piece in a Heathkit because it won't behave (Doing this to an It28 cap checker at the moment that does everything but check capacitors).


The battery in this meter is shot, but I am not understanding why it needs this battery. Can it work without one or is this the issue?

Sorry if these are dump questions. I've never had a tubed multimeter.