Fluke 8012A meter question

[k0uc]

I bought a used Fluke 8012A that has the battery option.

It doesn't work...preliminary testing shows that the DC-DC inverter isn't working.

Anyone have any experience repairing these old guys?
Something is not right in the power supply.

Next time I would buy one withOUT the battery option. I only would ever use it on the bench anyway.

I see lots of warnings in the manual about not running it without the battery and wonder if that's what happened.

Brady

[Conrad Hoffman]

Not familiar with the 8012 or battery option, but I've worked on similar stuff. My guess is it had NiCds, they went essentially open, and whatever filtering and limiting action they had, was lost. Every piece of battery operated test equipment I've got has been a problem in one way or another. Ideally, if you can find out how to convert it back to the non-battery version, that would be best. It may also be possible to replace the old NiCds with a large capacitor and a (big) zener diode. That will give you the filtering and limiting that looks like a battery, so the circuit works correctly. First, you need a manual/schematic, as troubleshooting will be difficult without it. That should also show how to get it back to non-battery operation. I've converted some of my formerly "weird" NiCd Fluke voltage references and GR equipment, to modern AA NiCds. Don't use NiMH, as they don't tolerate trickle charging well, and that's how all the older instruments worked. I've also converted instruments that used stacks of mercury batteries, to using stacks of old cordless phone NiCds, but that's another story.

[k0uc]

Good point...just change out the battery portion and make it AC only. I don't really care about battery operation.

Kind of a weak design relying on the battery to be there.

In the meantime I got an 8050A fluke that's a better meter anyway, but I'd like to get the 8012 going just as a project.
I enjoy working on this 'old' stuff. Guess I can use the 8050 to work on the 8012!

Tnx
Brady

[k0uc]

A while back I fixed the 8012A by replacing transistors in the inverter and putting in AA nicd cells.

Working like a champ now!

Just put in CHEEEP generic transistors (of appropriate specs).

I have an 8012A 8050A and an 8600A now.

Just over $100 for all 3. Nice to have one for current and one for voltage and another for resistance/misc.

Helps to avoid fuse blowing episodes...OOOPS I measured voltage on a current setting.

I found a place that sold 2amp AGX fuses for cheap. Email me if you need info.
B