Author Topic: Old DMM Failed Today (Read 2836 times)

sarbog · « **on:** April 15, 2021, 11:36:44 pm »

FYI,

I have been using an old early 1990's vintage Beckman 2020 DMM. It failed today on RMS voltage.. I spent an hour, embarrassingly, trying to figure out why my circuit was not working properly. Then it dawned on me that maybe this old DMM is not working. I did some comparison tests and sure enough it was my old DMM... Duh..........

Nusa · « **Reply #1 on:** April 16, 2021, 01:50:32 am »

Before you write off your old meter, make sure you try it with a new battery.

shakalnokturn · « **Reply #2 on:** April 16, 2021, 05:40:56 am »

If bad only on AC Volts / Amps check the few electrolytic capacitors around the TRMS converter.

sarbog · « **Reply #3 on:** April 17, 2021, 10:47:05 pm »

Yes, I will test the electrolytics, thanks.

rsjsouza · « **Reply #4 on:** April 17, 2021, 11:00:28 pm »

You may also want to keep mr modemhead's page to give your meter an extra life...

http://mrmodemhead.com/blog/beckman-3020-dmm-repair/

sarbog · « **Reply #5 on:** April 18, 2021, 12:01:27 am »

But, still want to buy the Dave Jones GW-121

Nusa · « **Reply #6 on:** April 18, 2021, 12:15:27 am »

His BM786 meter is also a solid choice.

Everyone who is serious about electronics ends up with multiple meters. Not considered a problem, so long as you don't spend the rent money.

tautech · « **Reply #7 on:** April 18, 2021, 12:21:54 am »

Quote from: Nusa on April 18, 2021, 12:15:27 am

His BM786 meter is ~~also a solid~~ better choice.

Sorta fixed that ^ for you.

sarbog · « **Reply #8 on:** April 18, 2021, 01:10:32 am »

A few pics of my multimeters since 1967, a Simpson 260, a Beckman 2020....... I have repaired both....

sarbog · « **Reply #9 on:** April 18, 2021, 01:11:43 am »

My Beckman....

sarbog · « **Reply #10 on:** April 18, 2021, 01:52:30 am »

Why is it better?

sarbog · « **Reply #11 on:** April 18, 2021, 02:09:35 am »

Playing with the design from Dennis Hilll about a digital ESR meter ...... got it working very cool stuff ........ Thank you Dennis Hill.....

Michael YYZ · « **Reply #12 on:** April 18, 2021, 02:19:19 am »

I’ve got the same identical one, although mine is branded as Wavetek. Love it! It works perfectly well, except some plastic tabs broke off from the case and rotary button and now the latter spins 360 degrees. But fine, otherwise. I checked the True RMS measurement against my new Siglent SDS2104X Plus scope and obtained similar readings.

https://www.eevblog.com/forum/testgear/hantek-dso5102p-different-measures-when-changing-the-coupling-(ac-vs-dc)/msg3549957/#msg3549957

I hope you’ll be able to fix yours...

Quote from: sarbog on April 18, 2021, 01:11:43 am

My Beckman....

tautech · « **Reply #13 on:** April 18, 2021, 02:27:27 am »

Quote from: sarbog on April 18, 2021, 01:52:30 am

Why is it better?

shakalnokturn · « **Reply #14 on:** April 18, 2021, 04:02:53 pm »

I used to own a Wavetek 2020 too, sold it in the end I had plenty more to hold on to, never got used the "menus" didn't like the feel of the function switch either.

sarbog · « **Reply #15 on:** April 30, 2021, 04:39:17 pm »

My new EEVBlog DMM arrived today... very nice!

sarbog · « **Reply #16 on:** August 31, 2021, 12:39:22 am »

Finally got around to taking my old Beckman Industrial multimeter apart.... model 2020 from late 1980's. It is working again on true rms ac + dc . I checked a lot of stuff, could not find any special true rms chips in it with a microcontroller... So I cleaned the big rotary switch, put it back together and now it is working.. very cool. Does anyone know how the true rms circuit is implemented
?

Tycho_Brahe · « **Reply #17 on:** August 31, 2021, 01:14:09 am »

Quote from: sarbog on April 18, 2021, 01:10:32 am

A few pics of my multimeters since 1967, a Simpson 260, a Beckman 2020....... I have repaired both....

Nice Simpson! I have that same model meter that I got used recently. I'm repairing mine now. A 138 ohm resistor is open. I suspect someone connected it up to some high voltage in resistance mode? Not sure. The Rx100 mode is the only range broken. Afraid more components are bad, but starting with the one I know about.

sarbog · « **Reply #18 on:** August 31, 2021, 02:15:59 am »

My first Simpson 260 I damaged in high school about 1969... cost me $200 for repairs........ was testing high voltage on my tube amp ham radio....


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Author Topic: Old DMM Failed Today (Read 2836 times)

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