Author Topic: Old Fluke Multimeters  (Read 187715 times)

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Online Vgkid

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Re: Old Fluke Multimeters
« Reply #25 on: October 31, 2013, 02:25:42 am »
Dr. Taylor:
Were you involved with the 892x series thermal rms meters?
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Offline mamalala

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Re: Old Fluke Multimeters
« Reply #26 on: October 31, 2013, 02:34:16 am »
drtaylor,

i'm wondering if you know anything about the 8502A? I have one here that i am restoring. One thing that is missing from the service manual is the schematic of the 04 option, the Cal.-Memory. While it is mentioned in the index, the pages are simply missing. Maybe you have any idea where they could be found?

Greetings,

Chris
 

Offline retiredcaps

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Re: Old Fluke Multimeters
« Reply #27 on: October 31, 2013, 05:53:46 am »
I left Fluke after the 8060, although I was working on the 77 A/D converter and TRMS converter. But the 77 came out after I left for Wavetek.

Another feature of the 8060 I was proud of was that it was the first DMM to have truly fast continuity.
There were some huge changes from the 8xxx to the 7x series.  Namely, 2000 hour battery life  :-+, autoranging with rotary knob switch and rubber holster.  However, none of the original 70 series has fast continuity.
 

Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #28 on: October 31, 2013, 05:57:24 am »
Dr. Taylor:
Were you involved with the 892x series thermal rms meters?
Yes, I was a team member on that one. I designed some of the options and ran most of the design testing. It was discrete opamps driving a Fluke developed thermal sensor that was a great TRMS converter capable of large crest factor readings. The Senior Engineer that designed that discrete op amp taught me so much. It was really an impressive piece of engineering. It strikes me as kind of funny now because you can buy off the shelf op amps much faster, but at the time, the only way to get the bandwidth was with discrete circuits. We did funny things like sticking two leads in the same hole to reduce lead inductance. It had an interesting anti-log circuit on the DC side of the sensor to try to improve the settling time. I have a prototype 8922 in my garage. Haven't fired it up for years. One thing that is interesting is the dB conversion was handled by a custom chip, not a microcontroller. That was actually the last non-microcontroled instrument I worked on as I went on the 8060 after the 8920 series came out.

One interesting thing about that development was the enclosure. An industrial designer at Fluke came up with an interlocking design and we were told that all bench instruments had to go into them. There were 3 heights available. Anyway, the industrial designer didn't provide for any ventilation, so you had to hang a heat sink out the back just to cool things. The 8920 went into that enclosure. Also I had designed that prototype Power Supply I mentioned in an earlier post into that enclosure too and had such a huge heat sink on the back so there was barely room for the AC jack.

To Chris (mamalala), I'm sorry, I had nothing to do with the 8502, actually a different business unit. So I have no documentation on it. I was in the handheld BU most of my 8 years at Fluke. I do know that cal memory tended to be battery backed CMOS SRAM and I wouldn't think it would be complicated. But the SRAM used is probably no longer available.

To Napalm2002, This weekend I'll see if it survived my wife's purges. At one time I had a box of parts, enough to build several 8060s and I had IBM color cases. So if I do, we can work something out.

To Modemhead, As far as I know, the 8020 was the first with that approach. Fluke stuck to their guns with the side pushbuttons for many years, the 8060 being the final DMM in that form factor. It was the competitive Beckman line of DMMs that made Fluke switch to a rotary. It was considered more elegant. It certainly was better sealed.

To all: I'll check this weekend for what parts I have that would be useful for restorations. I mostly have parts left over from the development of the 8060. But I also have a few 8020 family parts. I may be willing to part with an 8060 or two.
 

Offline kayvee

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Re: Old Fluke Multimeters
« Reply #29 on: October 31, 2013, 06:13:16 am »
drtaylor

Thanks for sharing your stories, all very interesting.

I have the same 8020A which was issued to me as a shiny new piece of kit, at first company I worked with, as my portable DMM.

We also had a few 8060's scattered throughout the lab.  When I left the company after 10 years they gifted it to me, and I still haul it out from time to time, which brings back those early days.

Okay, an LCD change or two over the years, but it still works like day 1.
 

Offline EEVblog

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Re: Old Fluke Multimeters
« Reply #30 on: October 31, 2013, 11:24:05 am »
I have many Fluke DMMs that are gathering dust, and I wonder if you'd like them for your DMM collection?

Umm, hell yes!  :-+
That would make one hell of a mailbag.
How much would the postage cost though?, what's the weight of this multimeter bonanza?
Thanks
Dave.
 

Offline EEVblog

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Re: Old Fluke Multimeters
« Reply #31 on: October 31, 2013, 11:28:00 am »
Somewhere I have the original hand drawn schematic of the 8060

That MUST be found and scanned in!
 

Offline Napalm2002

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Re: Old Fluke Multimeters
« Reply #32 on: November 01, 2013, 01:13:32 am »
dryaylor

That would be great. Hell I would very much like you to sign the back of the case. My kind of autographed baseball card but better!
 

Offline rsjsouza

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Re: Old Fluke Multimeters
« Reply #33 on: November 01, 2013, 02:19:10 am »
Dr Taylor, thank you for designing such beautiful equipment. In early 80's my dad and I used to drool over the 8020A's advertisements in the brazilian electronic magazines, but back in the day anything imported was way too expensive for simple hobbyists like us. Last year I was able to buy a 8020A with only two missing buttons (nicely supplied by Mr. Excavatoree) and gave it to my father - after 30+ years it is still incredibly precise and stable. It is my dad's main multimeter (he finally replaced his analog ICE).
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline echen1024

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Re: Old Fluke Multimeters
« Reply #34 on: November 01, 2013, 02:39:49 am »
Do you have an 8060 I could possibly buy from you? I love those old Fluke multimeters. My dad used one in college, and apparently, they had "destroy the fluke" contests with things such as overloads, shorts, and high voltage down the batt terminals. They would always spring back to life after a little fixing..
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #35 on: November 01, 2013, 02:49:52 am »
To rsjsouza, I started at Fluke just as the 8020 was being prototyped. So I cannot claim any credit for that one. I did set up the calibration stations, trained technicians, and worked under the chief Engineer of the 8020, Norm Strong. One thing that Fluke did to new engineers like myself, was make us spend many hours testing the meters while they were in the humidity chamber. Not fun. The 8060 which was a few years later when I had been promoted a few times, was my baby. But like all projects, it was a team effort.

To echen1024, I do have a few 8060 and 8062s in various states. It seems like I could find a ready buyer for them. So after I've done an inventory, I'll let you know.
 

Offline grenert

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Re: Old Fluke Multimeters
« Reply #36 on: November 01, 2013, 03:42:56 am »
I have a list somewhere of 8060 tricks, but one I remember off the top of my head, because I spent a lot of time designing that switch array to do it... If you pop out the two bottom switches, the input is connected directly to the A/D and the 10M divider network is disconnected. Therefore, like far more expensive DMMs, you get near infinite input impedance. Works only on the 200mVdc and 2Vdc ranges of course.
I have stickers on the back of my main 8060 with the "secret" settings :)
I also put together a little Pomona box with a 100M resistor to make a picoamp meter using the high impedance mode as suggested in the manual.  As others have said, that was an unusually thorough manual with great usage suggestions.
You can add me to the list of buyers if you find a spare IBM case and any side buttons.

EDIT:  I think there's a lot of potential here for another Amp Hour guest!
« Last Edit: November 01, 2013, 03:54:02 am by grenert »
 

Offline Flump

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Re: Old Fluke Multimeters
« Reply #37 on: November 01, 2013, 04:27:32 am »
heres my baby's  O0


 

Offline Lectricman

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Re: Old Fluke Multimeters
« Reply #38 on: November 02, 2013, 09:45:30 pm »
Thank you for your hard work in making such a long lasting and perfect audio meter! i collect these things and restore them so a little bit of USA made engineering will live on. (My wife thinks I am a lunatic) My personal 8060 was bought on ebay. It worked just fine but I went ahead and replaced the electrolytics since so many are dying from leakage these days. Here are a few (not all) of my Fluke toys I use to build and repair Tube audio gear.
 

Offline Flump

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Re: Old Fluke Multimeters
« Reply #39 on: November 02, 2013, 10:14:37 pm »
nice collection Lectricman  O0
 

Offline retiredcaps

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Re: Old Fluke Multimeters
« Reply #40 on: November 03, 2013, 05:48:37 am »
It worked just fine but I went ahead and replaced the electrolytics since so many are dying from leakage these days.
Good call.  All the electrolytic caps that were bad on my 8060A leaked from the bottom.  It is not obvious when looking at them until you physically remove them.

It took a couple of emails, but we convinced another forum member here to remove them and examine them.  Once he did, he discovered they had leaked from the bottom as well.
 

Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #41 on: November 03, 2013, 08:46:07 pm »
Mostly bad news. My wife did indeed toss out my 8060A parts box. I have no parts for anyone, and I'm truly sorry.

I have three 8060A's and 2 8062As all in good physical shape. Only the 8060A that I use at home for sure works. The others haven't been fired up in years. One of the 8060s is a blue IBM style, and one has a regular color case but with an IBM label.

I do have a lot of literature: Three 8060 user guides, one IBM user guide. Also about 30 copies of the "quick start" guide. I do have a copy of the original, not quite the production, schematic. I couldn't find my D size hand drawn schematic. I have copious design notes. I had forgotten how much that 7660 circuit gave me grief. It caused noise on the AC readings as well as false counts on the frequency counter. You can see in the original schematic (scan coming tomorrow), nothing had been done about that yet. An inordinate amount of time was spent on optimizing the PCB and plastic shield to get that 100kHz bandwidth.

As far as other Fluke oldies I have: D804 (a variant of the 8024) but its LCD is toast and the case is cracked. Good everywhere else so could be parted.  An 8050 4 1/2 digit benchtop. This was pre 8060 and didn't have any of the premium Audio features. I have one 8922 True RMS Voltmeter (with lots of design notes as this was my first extensive engineering project). I was the junior engineer on that one and did all the testing and optimization for the Sr Engineers. I have a rare 8860 5 1/2 digit DMM. I have an 8012 Benchtop, two 8020s, one a 8020A and the other and 8020B. I did find two A/D converters in antistatic foam for the 8020 (and all its derivatives).

Fluke was a player in Frequency counters back then. I managed to obtain two by trading people in other business units out of my hard model collection of 8060s. Those things were like gold back then. I have a 7220 125 MHz Freq counter with a 1GHz prescaler option. I also have a 7260 Universal Counter Timer (125MHz).

Other interesting stuff I found: The original announcement article published in Electronics Magazine under my byline. This is in good shape and I'll scan it for all you 8060 buffs. I also have two hand drawn pictures of 8060 concepts. One shows a much changed LCD that didn't come to fruition. The other shows a concept using two slide switches on the side. I was really gung ho on that one, but it was rejected as too radical. Also you can see it had a 10A input which didn't make it into the 8060. I'll scan these documents in and post them here tomorrow.

I also have User guides for all of the above units, so if anyone is missing a manual for their vintage Fluke DMM, drop me a line and I'll see if I have one. I found a maintenance manual for the 8020 as well.

Again, I'm sorry I can't deliver on parts for 8060s. I'm sure my wife was convinced my old Fluke stuff was junk. I tore my garage apart looking for it, but other than the complete meters listed above, it is gone. What's really sad is I had a complete box of all parts to make 10 or so 8060s with cases, LCDs, blank circuit boards, molded shields, custom switch arrays. etc. So sad.  My wife and I had a bit of a row when I accused her of tossing them. Oh well, life goes on.

« Last Edit: February 04, 2014, 03:17:47 pm by drtaylor »
 

Offline echen1024

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Re: Old Fluke Multimeters
« Reply #42 on: November 03, 2013, 10:25:12 pm »
Ugh. The wife.
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Offline Retep

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Re: Old Fluke Multimeters
« Reply #43 on: November 03, 2013, 11:16:37 pm »
Another feature of the 8060 I was proud of was that it was the first DMM to have truly fast continuity. A separate hi speed comparator was added to the A/D silicon expressly for this purpose. It doesn't depend on a conversion. I rate almost all DMMs by hitting the probes together as fast as I can. A fast continuity will beep. I'm surprised how many DMMs designers still don't get how important this is in troubleshooting.
Indeed. I always wonder why so many DMMs have such a slow continuity beeper. I mean, how hard can it be to get this right? The dirt cheap Hung Chang analog meter I got when I was 10 years old (and that is longer ago than I'd like to admit) had an instant continuity beeper, as does my 25 year old (also low end) Metex DMM. I admit those meters didn't have a latched continuity beeper, but I'd rather have an instant scratchy beep, than a latched beep that is 0.5 second late. A slow continuity beep is as far as I'm concerned close to useless. A 0.1 second delay I'm willing to tolerate, but if it is many times more than that they might as well leave the beeper out.
 
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Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #44 on: November 04, 2013, 01:57:16 am »
To Retep: Yes, the fast stretched pulse continuity detector, a must. I use the continuity in the 8060A all the time to check for shorts. On a large connector, you can place one probe on ground, and then swipe the other probe down every pin in under a second. The 8060 will detect a short that fast. In hindsight, I should have had that speed spec on the spec's published for the 8060. Perhaps, because I didn't, competitors didn't pick up on that.

I also found my original typed calibration procedure for the 8060 and 8062. I'll add that to all the scanning I'm doing tomorrow.

I mentioned old manuals, I have them for almost every DMM Fluke ever made up until 1985. I also have maintenance guides for a few. I suppose when DMMs got so cheap, spending time on maintenance guides was no longer worth it.
 

Offline kxenos

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Re: Old Fluke Multimeters
« Reply #45 on: November 04, 2013, 02:16:08 am »
drtaylor, you' re a true Jewell in this forum. Thank you for your work!  :-+
 

Online Vgkid

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Re: Old Fluke Multimeters
« Reply #46 on: November 04, 2013, 03:01:49 am »
I assume the frequency counters you are reffering to are the ones in the plastic 2patt lunchbox design, unlike the 195x series ones. Referencing the earlier hf thermal converters, they are a really interesting bit of kit.
If you own any North Hills Electronics gear, message me. L&N Fan
 

Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #47 on: November 04, 2013, 03:24:21 am »
I assume the frequency counters you are reffering to are the ones in the plastic 2patt lunchbox design, unlike the 195x series ones. Referencing the earlier hf thermal converters, they are a really interesting bit of kit.
It's funny you call that the lunchbox design, I know what you mean. The case series had a name which eludes me now, but I know is started with "Portable". Yes, I had the fortune of being on the team that designed the first product in that case, the 8920 True RMS Meter. That's when we discovered the thermal problems. The two Freq Counters I have are in the same package as you surmised, which was the medium size. They were designed to clip together to make a little stack. Three sizes were possible. I also have a systems DMM in the tallest package. I designed  a remote display into the short package, which was never produced. I don't think Fluke ended up with any products in the short version. Then there was my ill fated power supply design. That it was dropped was probably a blessing as getting the power high enough would have definitely caused a heat problem. I'll take a picture of that power supply and post it. It's definitely one of a kind.
 

Offline lowimpedance

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Re: Old Fluke Multimeters
« Reply #48 on: November 04, 2013, 05:20:44 am »
DrTaylor
 My old grey matter was wrong with actually trying the 7106 in the 8012a , must have just contemplated the idea long ago after deciding it was the same as the FLUKE chip !!. And to prove it I dug out an old 8010a and swapped the A/D with a 7106 and no it did not work  ::). Now its got me thinking if It could be made to work. (not that I need to bother!).
 I was going to ask about the 8050a , but I see it predated the 8060a, any similarity or lessons from the 8050 to the 8060 or completely different?.
As has been said by others these stories of yours give interesting hints to what happened behind the scenes. There is a ready audience for these types of reminisces.
 Thanks for taking the time to share.
 
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline drtaylor

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Re: Old Fluke Multimeters
« Reply #49 on: November 04, 2013, 05:22:24 pm »
8060 Documentation:

Copy of original schematic. This did not survive to production as I had to modify the 7660 circuit due to noise. But it is mostly intact to what ended up as the final schematic, which can be found in 8060 Manuals. It's funny now that I laboriously hand drew all those schematic symbols, some with a template. I got a lot of flak about only using a single squiggle for resistors, but I thought the meaning was just as clear.

Release article published in Electronics Magazine. This had some editing errors. The very last paragraph talks about Teflon Resistors which don't exist. Should read NPO Ceramic Caps and Teflon Trimmer caps. I think there are other minor errors. The editor took the text I wrote and "improved" it for publication without additional proof reading.

Cal Procedures for the 8060 and 8062 used by production. Written by yours truly.

My original concept sketches for the 8060. The earlier one proposed a dual slide switch on the side, but was deemed too radical a change from the 8020 series. The second was the one I did most of the design on and only at the last instance was the functionality changed. You can see a quite complex LCD in this, but the SM-4 couldn't drive that many segments at duplex.

I hope this proves interesting for aficionados  of old Fluke meters. My design process has always been design the front panel and define the feature set first, then see if you can come up with electronics that support it. That process I still follow today.

 
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