That's a '70s-vintage DMM I picked up while thrifting, it had 4 D NiCads in it which I recycled. There's a bit of leakage damage and a bit of "green meanies" on the PCB, but nothing huge.
It will probably work even if you don't put much effort into cleaning it.
But looking at it, I'm kinda surprised at the cheapness of the thing, I thought Fluke was supposed to be premium stuff or did they really improve in the '80s?
The most I ever paid for an 8000A was $10, so I guess I had lower expectations
I do like the 8600A quite a bit better though.
1) Needs a special AC cord
Not really, you just need an IEC cord with no shoulder on the socket. I'll bet you have something suitable.
2) Needs the batteries to work.
3) Uses an incandescent bulb as a current regulator for charging the cells.
As someone else mentioned, you can replace this stuff with a 1000uF capacitor and an LM317. I've found the DC-DC converter is usually happier with 5.5-6.0V rather than 5.0V, so use a trimpot.
Clever for the 1930s, but even in the '70s surely there was better?
There was an almost complete lack of cheap but effective NiCd charger circuits at the time. It didn't help that the 8000A is in a sealed case and gets quite hot inside, so sensing the battery temperature probably wouldn't work. If you were a business and had it cal-ed by Fluke, they would just replace the NiCds as a matter of course (take that, Mother Earth).
Is it worth putting in time and effort for what seems like a very basic DMM? Or should I keep it as a display gizmo?
If you like the look, a sort of fun thing you can do is stick a microcontroller inside and use it as a clock.
I was a little taken aback by the thing, very rudimentary, and now I see how easy it is to blow up the unobtainium front end.
I've never managed to blow one up though.
the board runs live mains right to the front panel next to all the signal lines. Fzzt.
Not on OP's battery version - the transformer primary is unswitched. Of course that's not so great since it's a crappy little transformer with a lot of leakage current.