Fluke 5130A Calibratoer - Page 1
Forum section: electronics / general

author: RikV
author_rank: Regular Contributor
timestamp: June 07, 2025, 01:21:41 pm
content: I ran into this device on ebay (Fluke 5130A Calibrator) and since I never heard of it I started to do my homework on Google etAl. No luck at all. After a lot of effort and time the only thin I found was a specs sheet. Rather impressive but far from sufficient to decion "to buy or not to buy". Remakable to me: the device has no user interface, only a fewconnectors on the back side, that's all.No manuals to be found at the usual sources either. Seems that without full documentation it must be of little practical use.Anyone out there who knows this beatiful (believing the specs..) thing? Any docs available?Since there is no UserInterface, how is it controlled? An external interface, GPIB....

author: aronake
author_rank: Frequent Contributor
timestamp: June 07, 2025, 01:34:07 pm
content: It looks like they have switches next to the GPIB port to set GPIB address. It is somewhat likely that same GPIB commands would be used for other Fluke Calibrators available at that time. Pretty risky but, but at right price, could be interesting.

author: Kosmic
author_rank: Super Contributor
timestamp: June 07, 2025, 01:44:33 pm
content: Look like the specs are similar to the Fluke 5100B/5101B.If you are lucky the inside and GPIB cmds are the same as a 5100B.

author: bdunham7
author_rank: Super Contributor
timestamp: June 07, 2025, 07:52:06 pm
content: This one?https://www.ebay.com/itm/396703535705I'm guessing along with the others above that this is a one-off or unusual GPIB-only version of the 5100A calibrator. The 5100A quickly was revised and became the long-running 5100B/5101B/etc series. I didn't read the specifications, which appears to be the only available documentation. It is possible other functions and features are missing compared to the other models. I see that it has no guard connections, no wideband output BNC and no 50R or INT/EXT Sense indicators so perhaps it doesn't do those things.I've overhauled a number of these types and that one on eBay looks beat--I'm feeling exhausted just imagining how much work it might take to make that unit fully functional. Last calibrated 30 years ago by Fluke (France) and now found in Lithuania. That must be a story.

author: RikV
author_rank: Regular Contributor
timestamp: June 07, 2025, 11:24:38 pm
content: bdunham7, Yes, that is the one. I came to almost the same conclusions as you do, but being GPIB-only would NOT be a no-go if only the specs of the 5100(A) were better. I see it was mainly intended for calibration of 4.5 digit DMMs. Back in 1990 these were probably state of the art but are these devices nowadays still of any use for 6.5 digit gear?On the other hand, it would be quite a challenge to bring this thing back to life, given the state it is in, just for the fun of it. Ithink i'm gonna make the guy an offer he can't refuse... Worst case I get stuck with some beatiful precision components I can't use.By the way, what were the main mods between 5100A and 5100B? Was 5100A that bad?What is the reference in these? (2x) LTFLU?

author: bdunham7
author_rank: Super Contributor
timestamp: June 08, 2025, 11:09:38 am
content: The 5100 series were (loosely speaking) 50ppm basic DC accuracy, ~350ppm for AC (the AC is actually pretty good) and they will meet or exceed that for the 0-20V ranges. Going above 20V they use a transformer plus feedback system that is tricky to keep adjusted and accurate. Slowing down the control loops helps, although it makes them not meet their stabilization time specs--that's just one of the many tradeoffs involved in setting these up. They were designed for 4.5-digit meters but back then the 5.5-digit meters were higher performance than most modern versions. So a properly adjusted 5100-series would be marginally acceptable for newer 5.5-digit meters as well, but nowhere near good enough for 6.5-digit. I have used mine to calibrate 6.5-digit meters using a parallel reference but the stability is really marginal for this purpose as well. Imagine trying to measure a part with a micrometer on a bench on a boat in rough weather.IDK the exact differences between A and B versions, I've seen exactly one 5100A in my life and it belonged to another EEVBlogger who was trying to fix it. It appeared, strangely enough, to be a brand-new unit--in the shipping crate IIRC-- that didn't work. The modules seemed to interchange and I don't remember the details well enough to say why they "upgraded". There were dozens of revisions to the modules, controller and firmware over the production of the 5100B units. The power supply board is especially problematic this way--I have 4 or 5 schematic versions and although I have a good general idea of the layout and can fix them, no actual board I've ever worked on exactly matches any of my schematics. If you're looking for a monumental challenge, go ahead and buy this unit--I'll be glad to help you through the fun of dissecting and analyzing it. The one stable and operational unit that I have now took many months to complete and I ended up swapping out every single tantalum capacitor in it.The references are Motorola SZA263, the predecessor to the LTFLU-1. This is the same as used in the higher-end calibrators and the 732A reference except that there's no oven in the 5100-series.

author: Kosmic
author_rank: Super Contributor
timestamp: June 08, 2025, 02:05:46 pm
content: The analog control board in my 5101b was probably replaced end of 1990 and it's equiped with a LTFLU. Kind of make sense since the SZA263 was probably not produced anymore back then.