Lafayette 99-50841 schematic
 

Just acquired a Lafayette model 99-50841 analog multimeter from one of the local thrifts. It's in A-1 shape, but I won't know if it fully works until I obtain an Eveready 504 15 volt battery (about $20!). If anyone has a schematic and/or a copy of the manual I would love to get a copy. Or a lead to a useful website. Thanks much!

I don't recommend buying the battery. I was faced with a similar need and took an old wall wart and that works fine. It's just for the highest resistance range(s). It's not a complex device and is probably nearly identical to many Radio Schlock models as well as other brands.

Yeah.
I did test it with a DC power supply to make sure those resistance ranges and the buzzer worked.
At least it had a brand new "AA" cell in it, and brand new test leads!
Bummer is there is no handle built into the cover-it's tippy.