WTB: Fluke 8800A/8810A Ohms Converter Board With Isolated DC-DC Supply. - Page 1
Forum section: electronics / general

author: whipaway
author_rank: Contributor
timestamp: July 02, 2017, 11:36:26 pm
content: Hi all,First, a little background on what I wish to accomplish:I have a few Fluke 8800A 's that use the old style ohms converter board that required two AA batteries to be used as an isolated supply for the current source.Newer 8800A 's and the 8810A 's used a new style of ohms converter board that did not use batteries, but instead used an isolated dc-dc converter to power the current source on the board.So, I am looking to buy a few of the newer ohms converter boards that use the isolated dc-dc supply in them, to install in my 8800A 's as a replacement for the battery-operated versions.Also considering the purchase of the AC converter boards (averaging or true RMS, I am interested in either or both) to keep as spares.Thanks,-Paul

author: hendorog
author_rank: Super Contributor
timestamp: July 03, 2017, 02:04:22 am
content: Hi Paul,Sorry I don't have any of those spare parts. However if you end up with a parts unit I am looking for a display cover in good condition - just the transparent red plastic piece which sits over the display.Regards,Roger

author: whipaway
author_rank: Contributor
timestamp: July 03, 2017, 08:39:54 pm
content: Quote from: hendorog on July 03, 2017, 02:04:22 amHi Roger,I will most certainly keep you in mind if I end up with a parts unit, but in the meantime you could fabricate a display cover from a piece of red acetate that you can find at an art supply store. Yes, it's ugly, but will help keep the innards clean and free of dust.

author: hendorog
author_rank: Super Contributor
timestamp: July 03, 2017, 09:45:14 pm
content: Quote from: whipaway on July 03, 2017, 08:39:54 pmThanks Paul. The current one is actually still intact - it just has some damage where some chemical has melted the surface of the plastic.

author: switcher
author_rank: Regular Contributor
timestamp: July 09, 2017, 12:26:42 pm
content: These are excellent meters, why not sell yours on, and buy one with a converter ? The AC and Ohms boards are like hen's teeth, as you are no doubt aware; there is one on Ebay, atm.The 8800As with batts are easy to spot; there is a note on the instructions on the bottom of the meter, again, there is one on Ebay, atm. So it seems a shame to change a meter from factory spec, as they are not particularly rare.ISTR the 8810A is TRMS, whereas the 8800A is not. AC and Ohms were factory options on the 8810A, and the 8810A is limited to 750VAC.Mine is a later one, and looking at the date codes on the chips inside, it was made around 1980, and is spot-on, against my recently calibrated 89. The spare fuse is still in the clip inside, which is a nice touch.If you are looking for a wel-spec'd, compact and relaible bench meter, they are an excellent buy.

author: whipaway
author_rank: Contributor
timestamp: July 09, 2017, 02:02:13 pm
content: Quote from: switcher on July 09, 2017, 12:26:42 pmAll of my 8800A ad 8810As have the ohms converter board, it is just that the ones in the 8800A use two AA batteries for the isolated supply, and I think that it is silly for a bench meter that is plugged into the mains to still require batteries additionally. I might consider adding a DC-DC converter in the place of the batteries, there are some low-cost and small isolated dc-dc converters that will output 3.3 volts, but I have to research a suitable input voltage for them, and they would fit nicely on the ohms converter PCB in place of the battery holder.My 8800As have the averaging AC converter in them, and my 8810s have the TRMS AC converter in them.At this point all my meters are fully calibrated and operational, but I would like to get some spare parts to have on hand so that I may be able to keep them operational well into the future.

author: switcher
author_rank: Regular Contributor
timestamp: July 10, 2017, 06:19:18 pm
content: I agree; its insane, for a mains-powered, lab-grade instrument to require batteries, what were Fluke thinking - basically expecting the Lab Tech to break the cal seals to change the AAs every year; madness.Unless it was derived from some military requirement. I know military sales were (are) heavily contested - for obvious reasons. Years ago, I remember coming across some obscure paper (online) regarding a 1970s court case between Fluke and Data Precision, regarding rights to tender (etc)

author: whipaway
author_rank: Contributor
timestamp: July 10, 2017, 09:36:44 pm
content: Quote from: switcher on July 10, 2017, 06:19:18 pmI remember reading about this case, Non-Linear Systems was also involved, the subject was the Fluke Model 8000A-01.