Equipment from the past - Page 1
Forum section: electronics / general

author: munorc
author_rank: Regular Contributor
timestamp: January 23, 2025, 04:38:54 pm
content: In the realm of old metrology related equipment, do people have any interest in equipment from years gone by? I have read the various posts on Weston Standard cells.I tend to collect and preserve old equipment more from a historical than practical use case.An example is this Leeds and Northrup Precision Potentiometer (model 8662). It was put aside mainly since it has a standard cell in it and it was a disposal issue. It has its original manual and the Standard Cell calibration data is from 1941. I have many more that have gotten stacked up in my office, along with mirror galvanometers and individual standard cells.

author: kbrill
author_rank: Contributor
timestamp: January 23, 2025, 09:52:57 pm
content: GE spark gap voltmeter

author: kbrill
author_rank: Contributor
timestamp: January 23, 2025, 09:56:36 pm
content: Somehow second photo did not upload

author: kbrill
author_rank: Contributor
timestamp: January 23, 2025, 09:57:44 pm
content: My foul up

author: trobbins
author_rank: Frequent Contributor
timestamp: January 23, 2025, 11:26:01 pm
content: Quote from: munorc on January 23, 2025, 04:38:54 pmI also enjoy restoring such vintage gear, and also appreciate anyone who has had the time to take photos and scan any manual and make comparison measurements as to its present accuracy. I've often enjoyed recovering the nominal accuracy of parts like manganin resistances that may have drifted or even broken coils, and surreptitiously upgrading galvanometers.I have a much more 'modern' L&N Millivolt Potentiometer 8690 with a good Weston cell that still appears to be working fine, but I'm putting off any serious accuracy comparisons or making up a modern replacement 1V ref for the Weston, until I come across a scanned manual.

author: munorc
author_rank: Regular Contributor
timestamp: January 24, 2025, 12:01:47 am
content: I find it difficult to locate any Leeds & Nothrup manuals. I plan on scanning the one I have for this, just to add to the available collection.I have 5 or 6 L&N Student Potentiometers, most of which are really dedicated to thermocouple measurements. I remember using a similar one back in my undergrad days, in a physics class. The 8662, although also aimed primarily at thermocouples, is also a bit generic in that you can use the sections separately. The manual even outlines using it to compare calibration of other standard cells, and the galvanometer can be used isolated from the rest of the instrument.

author: munorc
author_rank: Regular Contributor
timestamp: January 24, 2025, 12:20:34 am
content: I have this old reference from 1965, "Handbook of Electrical Measurements", published by Instruments and Control Systems. It has a lot of good articles on voltage standards, bridges, Kelvin Varley dividers, equipment for a standards lab, etc.I found a copy online here.https://babel.hathitrust.org/cgi/pt?id=coo.31924003627118&seq=1

author: Poroit
author_rank: Frequent Contributor
timestamp: January 24, 2025, 06:32:46 am
content: G'day munorc,Wow....your post brings back memories of lugging a L&N Potentiometer around brickworks ,plastic extrusion factories, abattoirs etc ....looking up Thermocouple Reference tables and compensating for Ambient Temperature.Modern Portable calibrators have certainly made a techs life easier.Do you have any local technical colleges who teach Instrumentation as you may be able to donate some of the gear.

author: munorc
author_rank: Regular Contributor
timestamp: January 24, 2025, 02:29:38 pm
content: Some other L&N examples. A Wheatstone Bridge (earlier version of the 4760) alongside a 2240A Light Beam Galvanometer. A few L&N Standard Resistors in the background.Second picture are three other L&N Galvanometers, two are 2285 Mirror Galvanometers, alongside an Eppley Unsaturated Weston Standard Cell.

author: munorc
author_rank: Regular Contributor
timestamp: January 24, 2025, 02:50:45 pm
content: Quote from: Poroit on January 24, 2025, 06:32:46 amI work for a University Engineering Department. Beyond the the items that relate to testing in the electrical realm, I have many other examples that fall in to the calibration and metrology realm for pressure, temperature, specific gravity, flow, etc. I have been working on getting the College to put these out on display so others can enjoy the items that were used in the past. Collecting them at works has also lead me in to collecting many items personally as well, especially gear made by General Radio.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 24, 2025, 02:57:57 pm
content: Quote from: munorc on January 23, 2025, 04:38:54 pmYou may like this youtube channel:https://www.youtube.com/@xofunkoxQuoteWhat is it the black wheel for, in the lower right corner of the wooden lid?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: January 24, 2025, 11:34:45 pm
content: I have a different piece of equipment with this handle. It is used to center the null meter. I can look up the instructions if you wish. It fits into the Right side of the case. Look for a connector. It essentially adjusts a pot which I suppose you are not to touch very much.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 25, 2025, 12:29:07 am
content: I've got a variety of old galvos, standards and meters. I stopped collecting them because they tend to take up a lot of space. Here's a nice L&N 300-ohm resistance box, probably custom for somebody. Also, a General Radio frequency standard. It uses a tuning fork with a carbon mic mechanical pickup and magnetic drive system. This is a photo off the net, but I have one that needs to be restored. Finally, a low-res photo of a L&N switch, usually used for reversing bridge connections.

author: munorc
author_rank: Regular Contributor
timestamp: January 25, 2025, 12:40:30 am
content: Quote from: Conrad Hoffman on January 25, 2025, 12:29:07 amI have one of those as well.I had a really nice switch, do not recall the manufacturer, that turned out to have non-sealed mercury wetted contacts. It ended up going out to the haz-mat team.Many of the artifacts I have collected at work have internal standard cells. I have had them all scanned and no mercury present, but they still pose a dilemma as to what to do with them.

author: Poroit
author_rank: Frequent Contributor
timestamp: January 25, 2025, 06:06:21 am
content: That Black wheel is probably a spare levelling foot.Those Light Spot Galvos are extremely position sensitive, so you have to adjust the light spot to the centre of the viewing window before you start measurements......fiddly!

author: munorc
author_rank: Regular Contributor
timestamp: January 25, 2025, 03:19:36 pm
content: Quote from: Poroit on January 25, 2025, 06:06:21 amThey have three pointed leveling feet. The small knob on the side is the micrometer adjust for setting the zero after leveling. The coarse zero is done with the knurled knob on top. Both act directly by moving the entire coil assembly.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 25, 2025, 05:02:37 pm
content: Quote from: munorc on January 25, 2025, 12:40:30 amI got rid of my standard cells, at least the guts. The unsaturated ones are all junk by now anyway, though I kept the nice thermally lagged cases thinking I could put a solid-state standard in there. I also got rid of my saturated Julie triple reference, though in hindsight I probably should have kept it. Or not, as they ran a bit hotter than most, which isn't good for the cells. I think the prettiest standard cell is the Weston-

author: tggzzz
author_rank: Super Contributor
timestamp: January 25, 2025, 05:55:49 pm
content: Quote from: Conrad Hoffman on January 25, 2025, 05:02:37 pmI like the internals of a 1949 cell even more

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 27, 2025, 04:29:18 am
content: Ever wonder what's inside a General Radio 1602-B UHF Admittance Meter? I've split it half so you can see the two sides. The body has the slots. The front carries three brass tubes with insulating washers in the centers. The center posts all connect to the detector connector on the front. The other side, shown here, has a wire connecting the center posts to the brass body. It's a one-turn loop. When you change the position of the levers, it rotates the wire loop to be parallel, perpendicular or at some angle to the slots. That determines the coupling. I don't remember how to operate it but you need a bolometer detector, a generator, a variable cap and some DUT. Man, this high frequency stuff is all just plumbing!When I put it back together, I'll get a shot of the front, or just Google 1602-B UHF Admittance meter. (edit- added)

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 27, 2025, 02:46:31 pm
content: Good Morning Munorc, I have always had a fascination with old technology. Thanks to you and Conrad for sharing your photos.And the others who posted pics.

author: HalFoster
author_rank: Frequent Contributor
timestamp: January 27, 2025, 03:21:38 pm
content: Somewhat OT but some great TE Eye Candy: Inside of a Rubicon 2781 Precision Bridge Potentiometer. They sure don't make them like this anymore...

author: HalFoster
author_rank: Frequent Contributor
timestamp: January 27, 2025, 03:23:00 pm
content: And another view...

author: munorc
author_rank: Regular Contributor
timestamp: January 27, 2025, 07:42:25 pm
content: Quote from: HalFoster on January 27, 2025, 03:21:38 pmNot really off topic. Metrology is about the science of measurement and how we tie measurements to standards. Precision devices like this are what lived close to the reference standards.

author: munorc
author_rank: Regular Contributor
timestamp: January 27, 2025, 07:45:07 pm
content: Another interesting reference from days past.

author: Vgkid
author_rank: Super Contributor
timestamp: January 27, 2025, 08:50:03 pm
content: Quote from: munorc on January 27, 2025, 07:45:07 pmThat is a good read , I have had it saved for years.