There's nothing wrong with the meter. You apparently have to enable the "line lock" for the meter to work otherwise it's grounded. (This is what manuals are for

)
"Eeww!" *removes dead stink beetles*
It also happens to be one of
those machines where it takes literally hours to temp stabalize, and there's no heater. However, the range switch is horribly dirty to the point where it's unreliable and one range is dead unless you force it to an exact spot. Does this have anything to do with the frequency increasing slowly over several hours?
Someone has also been inside to replace the line cord, as some screws are missing and the remaining two front ones are phillips. They also must have mangled the chassis screw threads as they were an absolute pain in the arse to get in without crossthreading, took me probably 10 minutes...per screw!

Everything else is still original and has anti-tamper goop on it.