B&K Model 290 Hi-Low FET Extended Range Multimeter
I have a number of VOMs, VTVMs and DMMs that I use on a regular basis. The reason for a variety of meters is each has some feature or function that's special to it, or maybe just more to my liking, than those on the other meters. Some of my meters have nixie tube readouts, some are analog, some are 75 years old, and some are modern digital wonders. And now I have one more, a new (to me) B&K Model 290 Extended Range FET Multmeter.
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The 290 has several features that I find useful and I think overall it's a gem of a meter. I especially like the easy-to-read 7" mirrored analog meter movement. It has 15MΩ input impedance and voltage ranges as low as 50mV FS. The ohmmeter has Hi (1.25V) and Low (33mv/42mv) voltage functions for troubleshooting transistors and logic componenents, and a Rx0.1 low ohms range with 1Ω at center scale.
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The first reference I found to the B&K model 290 is in a January 1974 magazine ad. It was advertised at the "low" introductory price of $139.95, still a princely sum for a poor electronics student like myself at the time.
For a little perspective on the price, as I recall I could eat a couple burgers, fries and a soda at McDonalds for about 98 cents. That's a lot of burgers. |
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The only part missing from the meter is the input probe, not an uncommon situation for meters with removable probes. But it should be relatively easy to build a new one. The original probe contained a 100KΩ resistor in series with the tip, and a switch to bypass it for a direct connection. The probe has a shielded cable and the body also needs to be shielded all the way to the probe tip due to the sensitivity to noise on the lowest ranges.
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A closep of the mirrored 7" meter face. A nice analog movement is perfect for much of what I do on the bench (not that digital meters don't have their place, too).
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Inside the meter looks to be completely original and doesn't look like it's ever had any parts replaced.
It's fairly light weight for its size. The sides are plastic and the case top and back looks like thin vinyl covered aluminum. It doesn't have the build quality of a military or high-end commercial meter, such as an HP, but it does offer extended ranges not usually seen on less expensive equipment, or even some high end meters. It's powered by a regulated AC power supply so there aren't any heavy batteries to add weight, or leak all over the inside. |
More to come...
Page created 11/21/2021
Last updated 11/24/2021
Last updated 11/24/2021
