Fluke 8840A - Page 1
Forum section: electronics / testgear

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: April 23, 2014, 08:11:54 pm
content: I found a Fluke 8840A at my local electronic surplus for $75. Not sure if its working, but do you think it is worth the price? Also how difficult would it be to repair if it does not work? Should I pick it up without testing it. I can go at lunch and get it but I wanted to know what the forum thinks.Thanks for your inputs.

author: edavid
author_rank: Super Contributor
timestamp: April 23, 2014, 09:01:03 pm
content: Quote from: Fluxed Matter on April 23, 2014, 08:11:54 pmThe 8840A has 2 options, AC and GPIB. For AC, you can't trust the checkmark on the back. If it has AC and works, that's an OK price, nothing special. If it has AC and GPIB, it's good.Watch out for aged VFDs (dim and stripy)... replacements are expensive.If the CPU is bad, it's really hard to find a replacement.Other problems can be fixed.Don't buy without a quick test.

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: April 23, 2014, 11:22:21 pm
content: Thanks edavid, I went back and checked it. I found this label on the side of the unit. Looks like it has both the GPIB and AC options. The last cal sticker I found is dated 1/05. Here's a shot of the label.edited for grammar

author: SeanB
author_rank: Super Contributor
timestamp: April 24, 2014, 05:01:51 am
content: Buy it, even if it is faulty and not repairable you could get your money back from parting it out.

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: April 26, 2014, 04:41:33 pm
content: SeanB thanks for the advice. I picked it up yesterday afternoon after a quick power on. More to follow.Sent from my iPhone using Tapatalk

author: Fraser
author_rank: Super Contributor
timestamp: April 26, 2014, 05:52:52 pm
content: I own three of these meters and they are still very accurate and when last tested were within specification even though last calibrated in 2005. Good meters if you find a decent one...... the usual high quality FLUKE design and production

author: linux-works
author_rank: Super Contributor
timestamp: April 26, 2014, 06:30:17 pm
content: I have one that I bought for about $80 or so. has gpib but can't seem to get it working, so the gpib card must be a dud.the meter is FAST and the display is HUGE. really nice in that respect.funny how fluke made ac measurements an 'option'. who would want a meter without ac measure ability? very strange way to market a high end meter..

author: Vgkid
author_rank: Super Contributor
timestamp: April 26, 2014, 06:57:09 pm
content: Thats just like how it is with the 850x series bench meters having ac/ resistance as an option.

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: April 26, 2014, 09:00:31 pm
content: Keithley also seems to have made AC an option on the older meters too. I have on that picked up for $5 dollars and it has a sticker saying DC only. After finding and reading the manual it said that AC was an option and the board was extra. Too bad mine did not have it.

author: linux-works
author_rank: Super Contributor
timestamp: April 26, 2014, 09:24:26 pm
content: options, options, options...I often buy items that have something missing from them, just to save some money. I saw a close friend of mine the other day... He said, "Stephen, why haven't you called me?" I said, "I can't call everyone I want. My new phone has no five on it." He said, "How long have you had it?" I said, "I don't know... my calendar has no sevens." -- Steven Wright

author: quint
author_rank: Contributor
timestamp: April 26, 2014, 11:14:39 pm
content: They really are very nice meters. I've had both 8840A and 8842A units at various times. I currently have an 8842A. Every one of them I've worked with have been very accurate, even long after the last cal. The main thing that seems to go bad (as it does with many similar instruments) is the VFD display. These gradually dim over time so make sure you get one with a good display. If you press the SRQ button right after powering the unit up it goes into a display test mode where all the segments are illuminated. Also, it is worth knowing about the extended diagnostics mode which you can enter by holding down on SRQ for a couple of seconds. That steps through various tests by number and displays an error code if anything doesn't pass. But Fluke still supplies a wonderful manual for these units including a nice theory of operation section and full schematics. They have a few Fluke proprietary ICs but most of the parts are discretes so they are easy to work on.A limitation to these meters is that they only can measure maximum 2A current. And ("trap for young players") like many bench multimeters, these have extremely high input impedance in the lower voltage ranges so the readings tend to float around and not return to zero when the leads are open circuit.One other thing I found out the hard way: Even though the 8840A and 8842A look and function almost identically the options are not the same. At least this is true for the GPIB board. The GPIB board for an 8840A looks exactly the same as the one for an 8842A but they have different part numbers and are not interchangeable. I don't know if this is true for the AC option but I'd be careful when buying one to add to a unit.

author: Fraser
author_rank: Super Contributor
timestamp: April 26, 2014, 11:44:53 pm
content: If your 8840A or 8842A has a dim or intermittent display, it is worth checking the filament voltage as dry joints have been found on the transformer and, due to its weight, the heater connections can become poor or intermittent over the years.See here:http://kuzyatech.com/fading-display-repair-on-fluke-8840aSome pictures of the units internals on that page as well. These units are well built, but the plastic PCB retaining 'rivets' can shatter due to age if an attempt is made to remove them. Should this occur, it must be addressed so as to avoid excessive PCB flexing. I have used M4 nylon nuts and bolts to replace broken plastic rivets.

author: DRT
author_rank: Regular Contributor
timestamp: April 27, 2014, 09:07:42 am
content: I have one of these - see this post for my teardown:https://www.eevblog.com/forum/testgear/fluke-8840a-bench-multimeter-teardown/msg133479/#msg133479Mine had a very dim display. It was suffering from dry-joint on the mains transformer problem. It's still fairly dim, but perfectly usable.

author: Kibi
author_rank: Unknown
timestamp: April 27, 2014, 09:25:30 am
content: I have also got one which needed some repair. It works perfectly now and is still very accurate.Here is my repair thread with lots of pictures for your perusal:https://www.eevblog.com/forum/reviews/fluke-8840a-teardown-and-repair/msg121986/#msg121986

author: FireFlower
author_rank: Regular Contributor
timestamp: December 04, 2015, 07:11:59 pm
content: 2015 purchase questionHello, I didn't want to make a new one so please ignore messages above this.I found a seller in Finland for Fluke 8840a who asks 220€ for 1/2014 calibrated fluke and 240€ for unit and 12/2015 calibration document.Worth of it? Ebay seems to be about 170€ with shipping costs, this unit seems to be in full working order.

author: commie
author_rank: Frequent Contributor
timestamp: December 04, 2015, 08:07:14 pm
content: Quote from: Fluxed Matter on April 23, 2014, 08:11:54 pmYeah, I use to have two of them, sold both of them awhile back, they are good voltmeters but the current range sux.

author: edavid
author_rank: Super Contributor
timestamp: December 05, 2015, 01:54:27 am
content: Quote from: FireFlower on December 04, 2015, 07:11:59 pmNo, way overpriced. You can get one from the US for much less, even with shipping.

author: FireFlower
author_rank: Regular Contributor
timestamp: December 05, 2015, 03:38:51 am
content: Yeah asked about in IRC also and they said it is over priced. I will buy it if seller sends it for me 170€ which is about the cost getting one from USA.

author: FireFlower
author_rank: Regular Contributor
timestamp: December 08, 2015, 03:32:21 pm
content: Offered him as a final offer 190€ including mailing costs. If he didn't accept then I will just keep looking for another source.