Mike,

I've recently repaired an AVO8 and a Russian 'TSE' 4313. In both cases
I needed schematics (how else to identify those burned out resistors).

The PM2412 had also some defect resistors (severely damaged by a
leaking battery), so that's why the need for schematics and/or service
manual.

IMHO, multimeters are difficult to service: lots of tracing, double
checking, how do the wires run, how do the switches work. Hmm, even
trying to understand how it works takes a few hours studying the
schematic for me ;-)

Grtz,

Peter.