Recent score from the 80s - thoughts on hacking old meters? - Page 1
Forum section: electronics / testgear

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 08:07:45 pm
content: I picked these two beauties up on craigslist from a (sort of) local contractor who's been retired for a couple years, by the sounds of it. I think these were rotting in a basement and neither worked, so I picked up the pair for $50. Turns out, the 83 had the standard LCD problems, solved easily with some IPA. I'm still not quite sure what's wrong with the 8060a, but after some taking apart and reassembling, it has taken to powering on and actually working most of the time, so I'm pretty pleased. They could both use a cal, but might actually still be within spec, and the 8060 is actually the more accurate of the two, go figure! Pretty psyched to have some more genuinely useful gear that's as old as I am.So the first project for when I have some free time is making a couple of cheap precision standards (to be cal'd against my actually-spot-on U1253A from that epic Grainger deal a couple years ago). But then after that, the 83's gotten me to thinking, gee, wouldn't it be lovely if this was actually an 87? It turns out, looking at the spec sheet, my original thoughts on that were misguided: the first-gen 87 was, according to the manual, a 4k-ct meter, where the 83 and 85 are ALSO only 4000ct. Leads me to wonder why the LCD is 1.8888. So the only real differences are accuracy spec. But just for giggles, if I wanted to upgrade it, what parts would I be looking at? Anyone ever gotten anywhere hacking the specs up on old meters? Perhaps something like 83-V to 87-V spec bump?

author: EEVblog
author_rank: Unknown
timestamp: March 13, 2014, 08:39:35 pm
content: There used to be a mod for the original 70 series meter that turned the 73 into a 77. It even had the unused button on the front, so you just had to move a jumper link.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 08:43:28 pm
content: Quote from: EEVblog on March 13, 2014, 08:39:35 pmAhh, that's JUST the kind of fun I'm looking for! Recall the spec difference off-hand? I've seen QUITE a few 73s around here lately for pretty cheap. 'Course, I haven't gotten one since they're pretty low spec even compared to the el-cheapo crap you can get for $30.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: March 13, 2014, 09:21:47 pm
content: You should check out a section of a website run by one of our members here:http://mrmodemhead.com/blog/fluke-8060a-repair/I recommend you check the capacitors he discusses. Plus, he has other notes about these meters.I've seen some old 70 series meters with a buttonless knob, every meter I've seen with a button is functional, but then again, I haven't seen them all.I should take some pictures and describe the change, if Mr.Modemhead hasn't done so already. I'll check his site first.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 09:31:22 pm
content: That's actually the very article I had up last night poking around to see what could be wrong, really great stuff over there! Has one on the 83 as well, but mine was a very easy fix in comparison. I need to follow up with a more in depth read in inspecting the 8060.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 13, 2014, 10:13:11 pm
content: Quote from: alexwhittemore on March 13, 2014, 08:07:45 pmThat is what I would pay for non working meters as well.QuoteIt is highly likely that both will be spot on compared to each other or +/- 1 count.QuoteThe original 80 series has full schematics and a bill of materials in the service manual. There is virtually no chance that a 83 is a 87 in disguise.QuoteIt was probably cheaper just to get one lcd that works with the 83, 85 and 87 rather than 3 different lcds.QuoteWhile the marketing and datasheets shows a difference in accuracy between a 83 and 87, it is likely both will be spot on wrt to each other. Modemhead buys non working meters and you can see in his photos, most of the meters are spot on with his references.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 13, 2014, 10:14:42 pm
content: Quote from: EEVblog on March 13, 2014, 08:39:35 pmThe mod that Dave is talking about enables "touch hold".https://groups.google.com/forum/#!topic/sci.electronics/rgEo-5NkMOoI can confirm it works as someone I know has done the modification above successfully.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 13, 2014, 10:18:10 pm
content: Quote from: Excavatoree on March 13, 2014, 09:21:47 pmIt won't be obvious at first glance that the capacitors are bad because they will be leaking from the bottom of the bung.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 10:19:13 pm
content: Quote from: retiredcaps on March 13, 2014, 10:13:11 pmThat'd have been my guess too, but everything I can dig up in the way of manuals for the first gen of the 80 series would suggest that the 83/85/87 were all, in fact, 4000ct, which is what has me confused. Maybe they knew they were planning to up that spec in a future revision and wanted to future-proof the LCD, given the large capital expense of tooling?

author: retiredcaps
author_rank: Super Contributor
timestamp: March 13, 2014, 10:24:23 pm
content: Quote from: alexwhittemore on March 13, 2014, 10:19:13 pmThe 87 can be put into 20,000 count by holding down the backlight button during power up. That is why the lcd powers up 1.8888.

author: EEVblog
author_rank: Unknown
timestamp: March 13, 2014, 10:34:08 pm
content: Quote from: alexwhittemore on March 13, 2014, 08:43:28 pmThe difference was the touch hold function. The button on the 73 (and 75?) did nothing, but was enabled on the 77, and it was just a through hole jumper setting.The 77 might of had a tighter spec though. Whether or no the 73/75 had the same spec and they were just marketing a lower number I'm not sure.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 10:44:01 pm
content: Quote from: retiredcaps on March 13, 2014, 10:24:23 pmSo I know the newest 87(V) has a 20k mode. I think as of series III, that was activated by holding the yellow button for one second. I think before that, it was a power-on option, but I can't find any evidence that the first gen 87 had the 20k mode. I'm also not sure as of which revision they went from 4k to 6k

author: EEVblog
author_rank: Unknown
timestamp: March 13, 2014, 10:54:15 pm
content: Quote from: alexwhittemore on March 13, 2014, 10:44:01 pmAll the 87 series meters in all model have always had a 4.5 digit LCD:http://assets.fluke.com/manuals/83_85_87smeng0500.pdfAnd the 87 has always been the one with the mode enabled.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 13, 2014, 10:55:36 pm
content: Quote from: alexwhittemore on March 13, 2014, 10:44:01 pmSeehttps://www.eevblog.com/forum/chat/i-need-to-know-the-history-of-fluke-87-(-1998-2010-)/

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 13, 2014, 11:15:03 pm
content: Ahh, beautiful, and good manual link Dave, thanks. Just for fun I quickly pulled off the cover and flipped the rubber switch panel around so I'd have a "yellow" button (below the blue button on the III and before). When I push it, I get a beep, presumably telling me backlight on and off. But the 83 doesn't have a backlight, so obviously not useful. When I hold it down during power-on, all I get is all LCD segments solid until I let go, no extra half digit, so it's at least not a totally brain-dead add-the-button hackEdit: Ahh, the main IC is at least labeled differently on the service schematic, so if it's not a totally different part (perhaps with a high-spec ADC), it's at least flashed differently or something. Bummer

author: Excavatoree
author_rank: Frequent Contributor
timestamp: March 14, 2014, 01:34:38 am
content: Quote from: EEVblog on March 13, 2014, 10:34:08 pmWell, I'll be. Honestly, I have many 70 series meters that I never use,so I've never checked to see if the button on my older 73s (75s?) actually does anything. Back when the 70 series was all I had, I had a 23 and a 77 with functional buttons. After that, I collected enough "higher end" meters that I never tried it. Strange what one can miss.I did see, at one time, on a pair of 70 models, buttonless knobs, but I added the jumper and replaced the knobs with the more common ones with the button and never looked back. I suppose someone, at one time realized that it was cheaper to have a common knob with button for all.EDIT: A brief check of my 70 series meters reveals that most of them are series 2, which have functioning buttons. The "no series" meters I have are all 23s or 77s, and have functioning buttons. I have only two model 70 meters, and they have buttonless knobs. So, my sample size, believe it or not, is too small. I don't have a meter with a non functioning button. Strangely, I notice that the firmware is different, some of the lower models lack the "touch hold" feature - the button only changes the range." On one of the 70 models I had, I added the jumper, and all I got was the range change - not touch hold. Looks like I still need to keep collecting these to get a good handle on it.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 14, 2014, 02:22:10 am
content: Quote from: Excavatoree on March 14, 2014, 01:34:38 amIt is my understanding that you have to move the jumper from the old setting to the new setting as per instructions in post #6.After that, you have to press down the button and then power on the meter to get touch hold. Pressing the button after you turn on the meter will result in nothing.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: March 14, 2014, 11:47:09 am
content: Thanks for the info;I'm sorry to be so confused.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: March 17, 2014, 08:44:47 pm
content: Quote from: EEVblog on March 13, 2014, 08:39:35 pmPlaying with this meter's got me thinking man, I'd just love to see a VINTAGE meter shootout