Old Fluke Multimeters

[drtaylor]

I would suggest that the PCB is likely getting mildly corroded, even if it looks good. I would use a stiff acid brush and scrub the land pattern with ISP, dry, then do it again. You can also take the round elastomeric, and with a soft, ISP dampened no lint cloth, wipe it down. The carbon can dissolve in ISP, so don't use too much on your cloth. Also, clean the glass contact area on the LCD with ISP, again with a soft cloth. Good luck!

[adinsen]

Thanks so much for your advice! I took it apart and as you mentions, I couldn't see any sign of corrosion. Perhpas a little around one of the connectors. It turned out, however, that I missed a purely mechanical failure, as can be seen in this picture. My attempt to fix the problem by increasing the tension of the elastomeric probably made it worse. At least I now have a large, clean face that I can apply glue on.

[qiran]

I got a Fluke 8024B with "PEACE PEARL" labels. Looks like it has been used by "PEACE PEARL" project.

About "Peace Pearl" program:
The 1986 "Peace Pearl" program with the United States included upgrading 50-55 J-8 IIs with US avionics, Martin-Baker ejection seats, and possible US engines for US$502 million. Two aircraft were flown to the US for prototyping, and work was underway by the time of the 1989 Tiananmen Square protests and massacre.Peace Pearl was cancelled by China in 1990; the US had permitted it to continue despite the post-Tiananmen sanctions.

[yo0]

Alternative replacement for broken/damaged LCD displays for 8010a, 8012a, 8050a and maybe others, all at AliExpress.

some wiring and labor needed for installation


Best regards

Pio

[blue_lateral]

Hello I'm new here, although I have been lurking for a long time. This is an amazing thread. I have just read all 38 pages of it for about the fifth time. Thanks to DRTaylor for starting this thread, and for giving us all this groundbreaking design in the first place. I have been a fan of them since the beginning. I couldn't afford one then, but one of my friends bought one when they first became available. Fast forward to the mid 2000s, I bought one and was using it as my main bench meter. You could buy nice ones then on ebay for about $35-$60. I bought another, and an 8062, and despite being from different sources and all having expired calibration, they all agreed out to the last digit. I was not aware of any chronic electrolytic capacitor trouble at the time. The main issue then was that the buttons rot and break, and Fluke no longer had new ones. I started collecting any of these "piano key" meters I could get, no matter how beat up or destroyed, just to get buttons. I scoured swap meets for broken ones, no matter what model. My goal was 3 nice working 8060as. Well, life got in the way, and all my test gear got packed away about 5 years ago. Most of it is still packed away. In recent times a friend of mine bought a 3d printer and.... we can make buttons! Maybe not quite the right colors yet, but I am working on that. I keep getting closer. I drug out all the piano key flukes. Most of the ones that had been so good no longer worked. That was kind of a bummer, but since buttons could be made, and potentially battery doors and stands too, I decided to take it further and try to fix all of them. Some of the "parts" units are 8020 variants. It's not likely I could fix all because there are parts missing, and displays for the 8020 variants are a problem even if I could make them all work. I have one 8020 display that works, one that is completely missing, and the rest are unknown but don't look very good. Anyhow here's the "collection":

[Excavatoree]

. It's not likely I could fix all because there are parts missing, and displays for the 8020 variants are a problem even if I could make them all work. I have one 8020 display that works, one that is completely missing, and the rest are unknown but don't look very good.

I know EXACTLY what you are talking about. 

[AVGresponding]

In recent times a friend of mine bought a 3d printer and.... we can make buttons! Maybe not quite the right colors yet, but I am working on that. I keep getting closer. I drug out all the piano key flukes. Most of the ones that had been so good no longer worked. That was kind of a bummer, but since buttons could be made, and potentially battery doors and stands too, I decided to take it further and try to fix all of them.

I printed a battery door for my 8060A out of white PLA, with an stl file from thingiverse. It works very well indeed.

[blue_lateral]

. It's not likely I could fix all because there are parts missing, and displays for the 8020 variants are a problem even if I could make them all work. I have one 8020 display that works, one that is completely missing, and the rest are unknown but don't look very good.

I know EXACTLY what you are talking about. 

ogdento made new displays for 8060a a couple of pages back, and also had a thread about an LED replacement design. I read all about that, as well as the project by robertbaruch to remake the LCD for the TRS-80 pocket computer.

https://www.eevblog.com/forum/projects/lcd-design-is-this-good-enough/

Eventually he also had displays made for the Sharp EL-5100 and maybe a couple of others. Dave has a series of EEVBlog videos on the subject as well, although ogdento and robertbaruch's LCD projects are most similar to the Fluke 802x displays. drtaylor had a thread gauging interest in 802x displays, and I think there was more interest in 8050A bench meter displays. It seems like there are so many bad 802x displays out there that someone should do it. I thought it might be me, but it don't believe I have the necessary skills yet to make the drawings, nor do I understand LCD technology in enough detail to write the specifications.

I am aware of the projects by mrmodemhead and others to convert 802x types to a pin-type LCD. That's pretty labor intensive, I wouldn't want to do a bunch of them. If I only need one display, I might do it.

[blue_lateral]

I printed a battery door for my 8060A out of white PLA, with an stl file from thingiverse. It works very well indeed.

So far I have done one in black PLA. I'd probably do ABS (like the buttons I have been messing around with) or ASA. I've still no found a color that looks like the color on the back of an 806xa Fluke. I don't expect to get it exact, but so far I haven't even come close. I continue to look. That's why I haven't done much with battery doors. I like PLA a lot, but you can't post process it with acetone, nor solvent weld it as far as I know. I would prefer ABS or ASA. My only PLA battery cover attempt so far works but is a bit flawed. I'll try again, but I may attempt to draw my own from scratch at some point.

[Dave Wise]

Is there a way to change the frequency of the 8060A's continuity beeper?  It's 2670Hz which is my hearing loss notch.  I can't hear it unless I hold the meter right against my ear, which makes continuity test unusable.

[DC1MC]

Is there a way to change the frequency of the 8060A's continuity beeper?  It's 2670Hz which is my hearing loss notch.  I can't hear it unless I hold the meter right against my ear, which makes continuity test unusable.

I have helped a friend with this problem, the solution was to install a very sensitive red LED on parallel on the beeper. Worked like a charm, it doesn't preserve the original historical aspec of the devecie but the friend wanted to actually use it.

 Cheers,
 DC1MC

[Dave Wise]

I'll keep that in mind, DC1MC; a light would catch my eye better than the LCD bar.  (I have to say, the bar is pretty good to start with.)  But I was hoping DRTAYLOR would say yes there's a jumper on the MAC chip.

I have an idea for shifting the frequency, using a SOT-23 microcontroller and FET in place of TO-92 Q6.  It should be possible to monitor the TONE signal and output a chosen frequency while TONE is active.  The interesting part will be programming the part to sleep between edges, something I've never done before.  Win or lose, I'll post results in a new thread.

[DC1MC]

I think this a job for Captain Padauk, I love the little guys, and think that it should be possible to reduce the freuency with little programminc effort.

DC1MC

[opabob]

I still like my ol' Fluke 77.  Not a -II or -III, just a straight Fluke 77.

On the bench I have an Agilent 34401, but still love my Fluke 77.

YMMV

[aeg]

Signal levels permitting, you could conceivably shift the tone down an octave with a D flip-flop, no programming required.

[Dave Wise]

That's tricky, because you also have to guarantee that your ending (idle) state doesn't pull current through R4 and run down the battery.  If you remove R4, your part must drive LS1 to B+ (9V) but the SOT-23 parts are all 5.5V max.  I'm almost certain I can write a simple program for e.g. PIC10F320 which is available at Mouser for less than a dollar.

I drove LS1 with a pulse generator and found that my ears hear it best in a broad range from around 800Hz to 1200Hz.  The 8024B is still a lot louder.  Here's the outline of the program.  It should work as long as TONE-prime's period is longer than TONE's.  See any problems with it?

Set system clock to LFINTOSC 31kHz.
Clock Numerically Controlled Oscillator from LFINTOSC .
Set up NCO in Pulse Mode.  Inc = 37444 (1107 Hz), width = 16 (516us).
GIE = 0.  (Disable global interrupts - sources still wake us from sleep.)
while(1) {
 preload NCO accumulator to overflow on first increment;  (So TONE-prime starts ASAP.)
 clear TONE wake flag; enable TONE wake;
 sleep;
 enable NCO; disable TONE wake; clear NCO wake flag; enable NCO wake;
 while(1) {
  clear NCO and TONE wake flags;
  sleep;
  if (N1OUT == 0 and no TONE wake flag) {
   disable NCO; break;
  }
 }
}

[blue_lateral]

What is the current wisdom on a replacement for c36 in the 8060a?

A while ago I tried to order all the caps on drtaylor's list. I was able (eventually) to get all those eventually except the Nichicon UTT 22uf aluminum electrolytics, which are discontinued. It seems the whole UTT series is discontinued, as is everything else I could find with a short enough length in 5mm diameter. I looked around and found a polymer cap from Kyocera, RPF0509220M035K. It wasn't in stock, apparently not in production yet. It was available for preorder at Mouser and DIgikey, so back in July 2023 I preordered some from Mouser, supposedly to ship in the first week of January 2024. The date has been pushed back several times, most recently to April 2, and I haven't got another delay notice from Mouser today so maybe they will ship tomorrow. There are also Kemet A759 polymers that rsjsouza suggested might work back on page 35. After the second or third time the ship date on the Kyoceras got pushed back I ordered some of the Kemets and I have those in my hand. They are taller than the original aluminum electrolytics by a lot, but it looks like they would fit. They do get really close to the processor circuit board above, and there is a bare via. It's a few thousandths clearance, and probably plenty, but I imagine I will try to insulate the tops anyway if I use them. One difference is the Kyoceras have a much worse leakage spec than the Kemets, but I don't believe it is an apples to apples comparison. I guess I will do some leakage testing at 9 or 10 volts when the Kyoceras get here and see how much worse (or better) for leakage the Kyoceras should be in an 8060a.

Any other currently available options?

[Dave Wise]

Here are my capacitor notes in case I recap my 8060A.  (There's no trace of leakage today and all the caps are name-brand and measure good.)
After comparing leakage, I rejected polymer.  I found long-life Aluminum electrolytics for all circuit numbers.  The original C19 is a low leakage type and the best we can do there is only 1000 hours, using Nichicon type UKL.  Tantalum is low leakage but I exclude it because I don't know the polarity of the applied voltage.

All my caps have Chemi-Con logo, all 85C but no series marking except
C19 47/16 is LL series, low leakage, with LLA as modern replacement.
Others are probably SR/SRC/SRJ, with SRA as modern replacement.
SRA and LLA are 85C 1000h.

Original Dimensions
C1,C23,C24,C32,C34: 100uF 6.3V 2.5mmLS/6.3mmDIA/8mmHT
C12,C21,C28 10uF 16V 1.5/4/8
C36 22uF 16V 2.5/5/8
C19 47uF 16V 2.5/6.3/8

Charge pump cap C21 10/16 can be 6mm OD
All caps can be 11mm tall
RMS cap can be 18mm tall
Polymer leaks 10x more than regular - REJECT

DigiKey except as noted

C1,C23,C24,C32,C34: 100uF >=6.3V 2-2.5 <=6.3 <=11.2
Chemi-Con ELE-160ELL101MF11D 10/16 10K 2.5/6.3/11 at Mouser
Kyocera AVX REF0609101M010K 10V 3K 2.5/6.3/11
Chinsan ER1C101MP26307RU 16V 3K 2.5/6.3/8
C12: 10uF >=16V 1.5-2 <=4 <=11
Panasonic EEA-FC1E100 10/25 1K 1.5/4/7
Chemi-Con ELXY250ELL100MD07D 10/25 1K? 1.5/4/8 at Mouser
Rubycon 35ML10MEFC4X7 10/35 5K 1.5/4/7 at Mouser
C21: 10uF >=16V 1.5-2 <=6 <=11
Lumimax AEC10M50V0511 10/50 2K 2/5/11
Nichicon UPW1C100MDD 10/16 2K 2/5/11 at Arrow
Chemi-Con ELE-500ELL100ME11D 10/50 10K 2/5/11 at Mouser
C36: 22uF >=16V 2-3 <=5 <=11
Panasonic EEA-GA1C220H 22/16 1K 2.5/5/7
Chemi-Con ELE-500ELL220ME11D 22/50 10K 2/5/11 at Mouser
C19: 47uF >=16V LOW LEAKAGE 2-3 <=6.3 <=18
Chemi-Con ELE-350ELL470MF11D 47/35 .01CV/3uA 10K 2.5/6.3/11 at Mouser
Nichicon UKL1E470KEDANA 47/25 .002CV/.2uA 1K 2.6/6.3/11 at Mouser
Rubycon 35YXM47MEFR6.3X11 47/35 10K 2.5/6.3/12.5
CERAMIC: Murata RDEC71E476MWK1H03B 47/25 X7S IR=10Meg 5/5.5/4/7.5 $2.50 at Mouser

HTH,
Dave Wise

[helius]

The 8060A's designer certainly schooled me about the desirability of solid polymer electrolyte caps in that instrument. You should at least read his advice and understand it, although you're free to select whichever components you prefer.

[blue_lateral]

I do appreciate the extra options Dave Wise listed. I would prefer to use polymer however to prevent electrolyte spillage if it is practical to do so. I have several of these multimeters, and some will not be repairable. I have identified two bad MACs, and one of them is in an 8062a that was working fine when I put it away about 5 years ago. There is board damage too. I imagine that was preventable. The amount of board damage from corrosion varies, but so far only one unit was free of it. 

[Dave Wise]

If you find name brand caps that leaked, please post about it.  I don't know whether my luck is due to part vendor or storage conditions.  I will certainly examine my 8024B after all the horror stories.

[blue_lateral]

My worst corroded 8060a is from roughly 1983 and all the electrolytics were black and marked Nichicon except C19. Corrosion ate 3 pins of the MAC socket, which I have replaced, and the MAC is also bad. There is a possibility the MAC may have already been bad, as this particular 8060a was not working when I put them all away about 5 years ago. It had a bad crystal too, that may have been the reason. There was blue corrosion on the legs of the TRMS chip, and I had to remove it to clean up the mess. I don't yet know whether it survived. There was some corrosion on the charge pump but not too bad, and it cleaned up without removal.

I bagged the caps and know which ones came from which units, most have no brand on the jacket. A couple more units had caps that looked exactly like the black Nichicons, but were not labeled as such. The evidence for exactly which caps were leaking and which were not is pretty much gone because I washed everything in isopropyl thoroughly before desoldering. Most of the caps that looked OK had fouled the pads directly underneath.

[Dave Wise]

I examined my 8024B, S/N 3990037.  It appears to work fine, with sharp black display segments.

The "Dark Pewter" button on the function switch is broken but looks like I can rebuild it with epoxy.  There are also two 3D-print templates at Thingiverse, once my local library gets a printer.  Thing numbers 2373469 and 5307572.

The secret to getting the boards out is you have to remove the shield screw.
The main board is Rev L and assembly Rev J, switch board Rev H and assembly Rev F.  There are 1984-1985 date codes everywhere.
The electrolytic caps are Chemi-Con with no visible leakage, the boards are sparkling clean except a bit of dust on the switch solder side.

The two switch board retaining pillars are covered in a "fur" of tin whiskers 
The amps shunt resistor on the switch board presses against the side of the cap on the main board, it has rubbed through the plastic sleeve.

I'm also working on the board layout and program for my 8060A beep frequency shifter.  Can't use LFINTOSC for the Numerically Controlled Oscillator, it's f+/-25%.  The choices are HFINTOSC (+/-3%) or external 40kHz clock from the MAC.

UPDATE.  I ordered parts and sent the board layout to OSHPark.  The program will use external clock.  Epoxy is setting in the broken 8024B button.  The 8024B caps read okay.  My instrument (which sports a battery threshold trimmer) is closer to the 1988 Rev 2 manual than the 1982 Rev 1.

UPDATE 2.  I rebuilt my 8024B's broken button with JB Weld slow 2-part epoxy.  I inserted a strip of business card with slits in the paper to clear the ribs on the bottom, wedged it in place with lengths cut from round toothpick, and filled the bottom and end with epoxy.  After it set I pulled off the paper, scratched off the residue, and filed down the excess.  I'll still 3D print, just to compare and in case my repair fails.  I think I'm ready to simulate my 8060A Beep Frequency program.

[blue_lateral]

There are 3 different buttons on Thingiverse. Some print better than others, but I have at the moment lost track of which I am using. One of the three has a window in the bottom like the original Fluke button, and that one did not print well for me. I am a complete beginner with 3D printing though, so someone else might do better with it. Still, one of the others is easier. What is Dark Pewter? Is that the lighter or the darker button?

The only "B" version I have of the 802x meters is an 8020B. It had 2 22uf electrolytics in it, They leaked and etched the board a little leaving it milky looking after cleanup and there is one damaged pad. I removed the caps, but have not replaced them yet as I am still waiting on my vaporware Kyocera 22uf caps which were after the last delay supposed to ship April 2. The last email said production completed April 5, and they were in transit to Mouser, estimated ship date April 29. April 29?! That suggests to me that Mouser will believe it when they see the the capacitors. No vertical space concerns in a 8020B though, so I could put something else in like the Kemet A759s.

[Dave Wise]

I didn't see the third 3D button template, what is it's Thing Number?