Analog Multimeter - refurbish?

[armandine2]

....I have and have had from "new" the type of multimeter shown in the video (purchased Hong Kong 1984?) - I more recently retrieved it from a leaky-roof-shed where I had kept it for a while.

 ... the other day I started to disassemble it and clean it up, and now I'm trying to figure out how it worked and might be refurbished.

I had no initial thoughts - but I am now wondering if it could be deepend to include a PCB layout to avoid the bird's nest of components around the switch.

[ebastler]

What would be your goal there? If you want to restore a "vintage" piece, because you have fond memories of using it decades ago, I would leave the internal setup unchanged and just clean it up. On the other hand, if you want a robust, working multimeter, why not just buy another digital one for $10?

[armandine2]

I am (surprisingly) not so short on multimeters, £10 or not.

...this one has little to no value, sentimental or otherwise, and that for me is its value  - i think the basic plastic structure is good. Not too sure about the meter movement. The parts are mixed: the two diodes look ok - not sure yet about the capacitor, one of the resistors is a leg short and the switch itself might be reusable - quite a few coils of wire, inductor looking? not sure where they were. 

the goal is still open - I am interested in wiring up the switch and seeing if it can be made to get near to measuring its ranges. The PCB would be through hole in the first instance. And help in rewiring attempt.

[r6502]

Hello all,

I have also some analog multimeters, that I'm using from time to time. I have 3 different types:

a: Metrix 202 B
no battery needed, if you do not use Ohms range good DC accuracy. Good for DC voltage and current, not the best for AC. my first multimeter I ever worked with.


b: Philips PM2505 electronic VAOhmmeter. It has a linear Ohm scale, really great! I love it. nice span of different ranges. 10MOhm input impedance.


c: Philips PM2504 electronic VAOhmmeter, bench top type. It has a also linear Ohm scale, and compared to the PM2505 a few more ranges. It has also 10MOhm input impedance.


From the Metrix I have a few. Sometime it is good to use them, e. g. if you measure the current of a PCB in different operating modes. You'll see very good a trend, if a measurement increases or decreases, mutch better then the modern digital ones with a bar-graph display.

I like of the Philips meters especial the DC ranges, as you do not meed to use the correct polarity for your measurement, they have a 2nd small instrument, indicating the polarity of the DC voltage or current.

Guido

[armandine2]

...as can be seen in the initial video, my meter is 2000 ohms per volt.

So not in the same league as above

[Analog Kid]

My vote, if it can be submitted, is to leave the original "bird's nest" wiring the way it was. That method works just fine for instruments like this.

I'm currently restoring a meter myself, an old VTVM (thread in this forum), one that's not particularly valuable or accurate, and I already have two others: it's like climbing a mountain "because it's there".

[Doctorandus_P]

I also have an analog meter (Handykit MK-2010BZ) and I still use it every now and then. It's nice for long term monitoring of a voltage or current. I have not put batteries in it, so the Ohms range don't work, but meh, who cares.

I would not spend a lot of effort into revising an old analog meter. A bit of cleanup to get it in working order I can understand, but that's about the limit.

Just had an idea:
Since I don't use the Ohm ranges of my analog meter, Modifying it into a battery tester may be worth considering. Batteries (Alkaline, Li-Ion button cells etc) are often still quite close to nominal voltage when nearly empty, but the voltage drops under load. Adding some resistors in the meter to draw 10mA to 200mA (depending on battery size) enables you to measure batteries under load, which gives a much better idea of their health.