EEVblog Electronics Community Forum
EEVblog => EEVblog Specific => Topic started by: EEVblog on May 13, 2021, 01:52:49 pm
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Dave takes a look at his favourite form factor multimeter of all time, the Fluke 37 from 1985
https://www.youtube.com/watch?v=NJhptTZpGPw (https://www.youtube.com/watch?v=NJhptTZpGPw)
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Dave, The 37 form factor was requested by corporate buyers because the small handhelds walked out the door too easily. Specifically it was made bigger to prevent theft.
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With the surface area on the top and low current drain you should make it solar powered.
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Magazine ads: "Fluke breaks the old mold. The Fluke 37. A bold new shape emerges with more features than any other bench DMM. Period."
$229 in 1986 ($558 today), 30kHz AC, 0.1% basic, autoranging etc., it had a new feature set.
In the 80's multimeter safety standards were in their infancy. Fluke 37 certified to IEC-348 which became 1010 (Cat. ratings) around 1988. So multimeters of the era have varying HV design (creepage and clearance) and input protection. Some are not great, others quite good. Fluke obtained the patents, which made it hell for other manufacturers.
Also, EMI susceptibility varied and total shielding was present in the decent brand multimeters.
In the Fluke 37 I see EMI-coated plastic for the cover and front panel, just beep it out with an ohmmeter and if aluminium flakes are coming off that would be bad.
For this form factor, the big "accessory compartment" is where your leads, probes or optional battery pack would go. It was only around a few years because you could put you lunch in there as well lol.
I remember the pipeline and electrical industries wanted the big battery pack because they spend all day on ohms/continuity and 9V battery life was too short. It was out in the bush, remote areas. So you will see other brands in the same FF have D batteries ~15,000mAh :o there.
Fluke 37 hinge clip fix (https://archive.org/details/thingiverse-4654920) stl files (4654920)
note, there's also 3D printer files for Fluke parts knobs, wall mount, magnet hanger etc. on Archive.org
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A good old Moldy Meter Teardown ! We love those !
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Dave, you asked about similar products from that time. For portable multimeters in the same form factor, Beckman had the 360, and 3060 which included RMS. I recall it having a 2000 hour battery life but that is hardly exceptional since it ran on 6 d-cells.
https://youtu.be/YAYZUjRe244
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Dave, you asked about similar products from that time. For portable multimeters in the same form factor, Beckman had the 360, and 3060 which included RMS. I recall it having a 2000 hour battery life but that is hardly exceptional since it ran on 6 d-cells.
https://youtu.be/YAYZUjRe244
Interesting. But still not the sloped front with carry handle.
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Are you trying to be Elon Musk and disrupt the multimeter industry? It sure could use it lol.
The lunchbox multimeter format is a flop- it's just too big, wasted space.
Only the ANENG 888S is a return to the rotated format which looks fine (aside from the alarm clock and Bluetooth music system (with no DMM Bluetooth). No ergonomic sloped display.
Conventional handhelds... no one really holds a multimeter in their hand when taking measurements, I need both hands for the probes. The DMM falls over, the bail collapses, maximum LCD glare etc. just gross.
I have a Beckman 360 in my collection somewhere, it has a 20R range w/zero pot, thermocouple input, AC+DC TRMS switch. It's 2,000hr life on a 9V battery, the "D cells were better with the high ohms current on 20R scale I thought. Beckman USA and Fluke competed head-head back then.
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Dave, you asked about similar products from that time. For portable multimeters in the same form factor, Beckman had the 360, and 3060 which included RMS. I recall it having a 2000 hour battery life but that is hardly exceptional since it ran on 6 d-cells.
https://youtu.be/YAYZUjRe244
Interesting. But still not the sloped front with carry handle.
It has a folding carry handle and internal compartment.
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Instead of D cells, you can use a rechargeable lithium pack the size of 1 or 2 D cells. Properly maintained, with a quality battery pack, you wont need to worry about battery leaks and you will get a few thousand of hours of life after a 1 hour charge with a good 65 watt charger, even after the battery has aged with a decade of use.
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Here's some pictures of mine:
https://www.eevblog.com/forum/testgear/fluke-37/msg3448284/#msg3448284 (https://www.eevblog.com/forum/testgear/fluke-37/msg3448284/#msg3448284)
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Interesting. But still not the sloped front with carry handle.
Something I just noticed is that the carry handle acts as a bail to tilt the whole instrument upwards.
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Hi Dave,
I just got one of these that is missing the flip stand. Anyone have a 3 D model for it? Also you mentioned making a 3D model for a short case. If you do that I would certainly be interested.
Sam
W3OHM
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Dave, you asked about similar products from that time. For portable multimeters in the same form factor, Beckman had the 360, and 3060 which included RMS. I recall it having a 2000 hour battery life but that is hardly exceptional since it ran on 6 d-cells.
https://youtu.be/YAYZUjRe244
Interesting. But still not the sloped front with carry handle.
Metrix MTX 3250
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One the other side of the front panel PCB:
(https://i.imgur.com/dEUojde.jpg)
(https://i.imgur.com/ujfqzWb.jpg)
https://i.imgur.com/lUPLH0O.jpg (https://i.imgur.com/lUPLH0O.jpg)
https://i.imgur.com/7bvu3Jd.jpg (https://i.imgur.com/7bvu3Jd.jpg)
https://i.imgur.com/0Sd83Ph.jpg (https://i.imgur.com/0Sd83Ph.jpg)
https://i.imgur.com/a0WDttx.jpg (https://i.imgur.com/a0WDttx.jpg)
https://i.imgur.com/dgJN52L.jpg (https://i.imgur.com/dgJN52L.jpg)
https://i.imgur.com/P62e16b.jpg (https://i.imgur.com/P62e16b.jpg)
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One the other side of the front panel PCB:
:-+
I didn't take mine apart that far. I didn't think there would be much there and I didn't want to disturb the zebra strips..
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This meter must have made Fluke 27 look small. It also looks like it was designed for left handed people.
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This meter must have made Fluke 27 look small.
Yep.
It also look like it was designed for left handed people.
Nah. "Cable sockets on the left" is definitely designed for right handers.
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There is a PTC on the board it is a rectangular one. Also the terminals on the battery connector are called AMP-IN terminals. They make these for all sizes of wire. A great product.
Sam
W3OHM