Fluke 8060A Calibration Service? - Page 1
Forum section: electronics / testgear

author: thared33
author_rank: Contributor
timestamp: March 25, 2018, 10:30:00 pm
content: I got a Fluke 8060A multimeter on Ebay a while back. It's actually in very good cosmetic condition with a near perfect display. Everything seems to work fine except when I test for voltage or decibels. The readings are definitely off. I don't know if it just needs to be calibrated, or if it needs an actual repair. I don't want to just chunk it. I want to save and use this beautiful machine.Does anyone know of a place or a person that I can send this into to be looked at? If it comes to it I can replace/solder some of the parts myself since I found instructions for that, but I'm not sure I have days on end to spend repairing it. I'd like to get it working in any case.

author: Fungus
author_rank: Super Contributor
timestamp: March 25, 2018, 11:48:58 pm
content: What's the serial number? That gives an idea of age.It may be that the capacitors have given up and/or leaked all over the PCB. Even if they haven't leaked they should still be replaced ASAP. Old electrolytics lose capacity, stop working and if they leak they can corrode the PCB and destroy the meter.Calibration is easy, just connect up a voltage reference and twiddle the appropriate potentiometers. See manual for details. You could start by trying to get it to agree with another meter. If it gives you problems then suspect the capacitors.Here's some guidance from the guy who designed the meter:https://www.eevblog.com/forum/testgear/old-fluke-multimeters/msg1288190/#msg1288190Part numbers for replacement caps are in the post above that one.

author: drtaylor
author_rank: Regular Contributor
timestamp: March 25, 2018, 11:50:52 pm
content: Most likely you have leaky electrolytic caps. There's one right next to the AC Converter that can cause ACV to be off. I assume you meant that AC Volts was off since you also mentioned dB. If DCV is reading wrong, then you have more problems. This will not be solved by calibration. Take the board out and examine around all the electrolytic caps looking for electrolyte leakage. This is all that usually goes wrong with 8060s. Mr Modemhead has well illustrated repair guides for the 8060A. I was the designer of the 8060A. You can see more discussion on the 8060 in the "Old Fluke Multimeters" topic. I have 12 8060s that all needed new caps, but are now functioning beautifully. Pretty good for a 35 year old design.

author: Fungus
author_rank: Super Contributor
timestamp: March 26, 2018, 12:21:44 am
content: Quote from: drtaylor on March 25, 2018, 11:50:52 pmhttp://mrmodemhead.com/blog/ibm-8060aaa-fluke-8060a-refurbish/

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 02:16:33 am
content: The serial # is 3340537, located at the top back, etched into the case. The mainboard is a revision F. How old is this one?ACV is what I was testing drtaylor, you're right. I'm using this primarily for audio gear testing/calibration, but only simple stuff like testing output levels to make sure my studio gear is working fine. ACV and DB are definitely both off. An electrical outlet shows 143V on the 8060A but my cheap $20 Innova shows 122V which is obviously more accurate. DC is reading fine on the 8060A though. A new 3V coin battery and a new 9V battery both tested slightly above 3V and 9V, respectively.I looked for some leakage but I'm not seeing anything too major. But I'm also not sure exactly what I'm looking for either. There is what appears to be a little EPROM type looking chip that has some green residue on its legs. It says FLUKE RMS on it and what appears to be a little drop of paint or something.I solder mostly cables but have soldered in a couple things on boards before. If you think this is an easy fix and I can do it myself then I'll take a swing. I wish I had someone that could recap and calibrate it for me though

author: lowimpedance
author_rank: Super Contributor
timestamp: March 26, 2018, 02:49:32 am
content: That chip is the RMS IC and the green is corrosion caused by the leaking electrolyte from that nearby electrolytic cap.You need to removeALLthe electrolytics and clean the PCB thoroughly to remove all traces of electrolye and corrosion, see the linked site to Mr Modemhead.Repair any damaged traces and install new caps.

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 04:32:23 am
content: I'm looking at the instruction manual but the layout of the caps doesn't quite match up with my own multimeter. The manual says at the top that it's for serial numbers 6851 and higher. Mine is way lower. Is there a diagram available that shows where the caps are?

author: lowimpedance
author_rank: Super Contributor
timestamp: March 26, 2018, 05:08:30 am
content: Your meter layout is the same as the 8060a in modemheads blog, I would follow what he has done. He even lists the caps he used in the repair..

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 05:29:05 am
content: I'm not seeing a layout anywhere on his blog. I took it that I'd have to look in the manual. The manual doesn't seem to indicate where at least a couple of the caps are. For example, there is a cap directly below C36 on my meter but it's not listed in the layout which is attached, and C19 which I see on his blog is nowhere to be found in that layout either. Maybe I'm overlooking something or there was a service manual available that I need.

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 06:23:15 am
content: I was able to locate and remove C12, C1, C36, C23, C34, C32, and C21. I see two more caps around that RMS chip (above and below it or so) for a total of 9. I don't see those other two I'm seeing on mine in the page I uploaded. There are supposed to be 10 though so I'm not sure what I'm missing.

author: Fungus
author_rank: Super Contributor
timestamp: March 26, 2018, 07:28:06 am
content: Quote from: thared33 on March 26, 2018, 02:16:33 amLate 1980s I think.If you lift the screen assembly off there will be a datecode on the chip underneath in the form WWYY (week, year).

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 08:59:12 am
content: It's underneath the chip? Because mine does say 1983 on it.I spotted which cap is missing on mine. It's the one farthest to the bottom right, near those 4 white things (mine are blue). Check the attached photos to see what I mean. Mine has a little puddle of solder in both of those holes and that was definitely done at the factory. I'll have to get someone to chime in and see what's going on with that.I have a new batch of IPA on the way as well as all the caps from Digikey. Just need to be filled in on which caps go where as mentioned earlier.

author: Fungus
author_rank: Super Contributor
timestamp: March 26, 2018, 09:58:04 am
content: Quote from: thared33 on March 26, 2018, 08:59:12 am0890 = Week 8, 1990

author: thared33
author_rank: Contributor
timestamp: March 26, 2018, 10:15:49 am
content: Mine says:FLUKE6127131983241E

author: Fungus
author_rank: Super Contributor
timestamp: March 26, 2018, 10:56:48 am
content: Quote from: thared33 on March 26, 2018, 10:15:49 amIs that photo of your meter?

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 26, 2018, 12:38:58 pm
content: Quote from: thared33 on March 26, 2018, 08:59:12 amC28 is a 10uF across the 1.2V bandgap reference. To be honest, I hadn't noticed that it disappeared at some point in the lifespan of the design. I have hardcopy documentation from 1983 and 1988. C28 exists in the 1983 rev, but is not mentioned in the 1988 and the much-later PDFs available on-line from the Fluke archives.If it is not in your meter then there should be no need to include it.On a side note, just a few days ago someone asked me about schematics for the older RMS converter section. I scanned a few key pages of my 1988 manual and made it available in a zip file:8060A_Rev3-0188_Manual_Scans.zipFor completeness, I probably should repeat the exercise with the oldest hardcopy I have, which is a 1983 manual for the IBM 8060A/AA. It does include C28.I'll add the link here when finished.8060A-AA_Rev1-0183_Manual_Scans.zip

author: thared33
author_rank: Contributor
timestamp: March 27, 2018, 01:00:02 am
content: Quote from: Fungus on March 26, 2018, 10:56:48 amMine was posted earlier. The other one I took from Modemhead's blog.Modemhead: Are you sure that cap disappeared later on? Because if the date on my chip is correct (1983), very early models might not have come with it. It seems like later models didn't either though, if your documentation is accurate.I got all 9 of the caps out. A few have crust on the holes so I'll clean them with IPA and resolder everything when my digikey package gets here. The ICL7660 looks fine but I haven't tested it. The 40-pin socket looks fine too. The only thing I'm concerned about is that there is green stuff on that RMS chip's legs. I hope a good scrubbing is all it's gonna need.I'll update the thread when I get the good caps in there in a few days.

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 27, 2018, 02:20:56 am
content: Quote from: thared33 on March 27, 2018, 01:00:02 amNo, I can't be sure. All I know is that C28 appears in the oldest documentation I have (the 1983 IBM 8060A/AA manual), and is not present in any later docs that I've laid eyes on. It has been physically present in the units I've recapped, which are all fairly old, serial numbers starting with 3 or maybe 4. So I hadn't noticed its possible absence before.A curious person might ask why the unit I was re-capping that is shown in the photos above has a MAC chip with a 1990 date code. Since the other chips have 1982 date codes, I'm guessing the MAC chip was replaced at some point. It previously belonged to a retired IBM tech so I don't know its history.

author: Fungus
author_rank: Super Contributor
timestamp: March 27, 2018, 06:32:22 am
content: Quote from: thared33 on March 27, 2018, 01:00:02 amOK, I was confused by all the photos. I'd expect a 1990 meter to have a number that starts with a 4, not a 3.Quote from: ModemHead on March 27, 2018, 02:20:56 amOk.Quote from: thared33 on March 27, 2018, 01:00:02 amProbably a copper salt. Try warm water, a cotton bud and plenty of elbow grease (it can take a while to dissolve).

author: thared33
author_rank: Contributor
timestamp: March 29, 2018, 01:17:44 am
content: The AC voltage reading isn't working at all after recapping. An electrical outlet won't give a reading and only goes to 0.02V. When I power it on while holding the continuity button I get about 99.95, so that's a good sign I think.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 29, 2018, 05:19:51 pm
content: I would double check your soldering and check you didn't install a capacitor backwards or something.Check the Switch Decoding Self-Test and see if ACV works properly. Page 5-22 shows the procedure. In addition, go through the voltage test AC troubleshooting guide and check the test points documented.

author: retiredcaps
author_rank: Super Contributor
timestamp: March 29, 2018, 05:24:54 pm
content: On my used Fluke 8060A that I bought off ebay, it wouldn't even power up due to leaking capacitors. After I replaced them, AC was off. Some electrolyte had leaked into the legs of the AC pot. I turned the AC pot all the way to left and right three or four times and then adjusted it. Turning the pot I suspect helped remove some of that electrolyte that had wicked up?

author: thared33
author_rank: Contributor
timestamp: March 30, 2018, 01:35:28 am
content: All numbers on the switch test are coming up normally. I don't think there is an issue with soldering, but I'm going to double check and maybe resolder a point or two if I have to. All caps are installed in the proper polarity for sure, as I can tell by comparing Modemhead's cap positions.I'm looking at the test points from the documentation Modemhead provided but I'm not really finding the right place to test, since I'm not very knowledgeable about this kind of stuff. I'm spending hours trying to fix it, so if it doesn't work out soon I think I'm better off just buying a newer multimeter since this isn't worth my trouble.EDIT: I looked for this AC pot as you say but I can't find that either. Is there an actual service manual that's different from the user's manual? Not sure it matters at this point because I really don't want to fool with it any more. Maybe you experienced tech guys can fix this easily, but this is becoming way over my head.

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 30, 2018, 02:10:45 am
content: Quote from: thared33 on March 29, 2018, 01:17:44 am9995 on the ratio test does indeed mean the ADC is working, which is a good thing.DC volts and ohms are working OK, but AC volts is not, is that correct? If so, then I have some basic RMS converter trouble-shooting suggestions you can work with. Voltage measurements are made with respect to the 8060A COM jack.Set the 8060A to 200mV ACV range.Connect a stable AC source of 190mVrms, sine wave, 200Hz to the 8060A input jacks.Measure theACvoltage at U2P5. It should be a little less than 190mVrms, due to loading from the working DMM's input impedance.Measure theDCvoltage at U2P10. It should be about -190mV DC.If you do not have a signal/function generator, a function generator app running on a phone/tablet will work for the test signal source. Connect one channel of the device's headphone jack to the meter.

author: thared33
author_rank: Contributor
timestamp: March 30, 2018, 09:11:41 am
content: Is there a service manual that I'm not aware of? Because I keep seeing hearing about places to check on the meter's board but I have no idea how to locate them. From what you say I think U2P5 and U2P10 means the RMS chip, and pins 5 and 10. Not sure how the pins are numbered. (Note: that green stuff never came off the RMS chip, so maybe that's the problem...)Forgive me for asking such rudimentary questions, but:There's a positive and negative side of a balanced cable that I can run out of my audio interface to get .190V. I also have a Leader 192A sitting around, and it has a red terminal and a black terminal (I guess red is positive and black is negative?). If I get one of those set up with .190V, should I run the positive side to the red input on the 8060a and the negative to the COM jack?After that's set up I can use my other cheap Innova meter to test once I find the right pins. There's a red and black cable for it just like on the 8060a, and I think the red one will go on the pin, but where should I stick the black one?I appreciate everyone that has taken time. I know it's a hassle to teach an ignoramus

author: Fungus
author_rank: Super Contributor
timestamp: March 30, 2018, 10:49:25 am
content: Quote from: thared33 on March 30, 2018, 09:11:41 amYes.Beware that there's a few versions. Later meters had the RMS chip on a daughterboard, I think you want a manual where the RMS chip is on the main board.http://www.download-service-manuals.com/en/manual.php?file=Fluke-9271.pdfQuote from: thared33 on March 30, 2018, 09:11:41 amYes.Quote from: thared33 on March 30, 2018, 09:11:41 amMaybe.Quote from: thared33 on March 30, 2018, 09:11:41 amYes.Quote from: thared33 on March 30, 2018, 09:11:41 amOn the COM terminal.

author: thared33
author_rank: Contributor
timestamp: March 31, 2018, 08:16:45 am
content: Quote from: ModemHead on March 30, 2018, 02:10:45 amI got a sine wave running at .199V @ 200hz which is close enough. I clipped some alligator clips onto the TRS cable, ran the red wire/tip to the red input on the 8060A as well as the black/ring to the COM jack. I also put my other multimeter's black lead into the COM jack on the 8060A while the alligator clip from the TRS cable was on it simultaneously, and pin 5 as noted below gave me a reading of .196V AC. Close, so I think that's fine. However what I believe to be pin 10 is going to 0V on DC. I believe the pins are numbered like so when looking at it from a normal use position and the top case popped off:Quote

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 31, 2018, 12:20:56 pm
content: Your pin numbering is correct.So, you've found a good input and a completely missing output for the RMS converter. But before putting a nail in its coffin, check that it has a proper power supply.Measure the DC voltage at U2P4 (Vdd). It should be about 5.2V. Measure the DC voltage at U2P8 (Vss). It should be about -5.1V. As usual, black lead of your Innova on the 8060A COM jack, red lead on the pin. It is not necessary to hook up the 190mVac test signal for this check.

author: thared33
author_rank: Contributor
timestamp: April 01, 2018, 01:41:30 am
content: P4 is 5.14V DC and P8 is -4.98V DC. I guess that's a good sign.

author: ModemHead
author_rank: Frequent Contributor
timestamp: April 01, 2018, 01:04:58 pm
content: Quote from: thared33 on April 01, 2018, 01:41:30 amYou've determined that the RMS converter chip is powered up, has a good input, but has 0V output. That means either the converter chip is bad, or some other fault is making it look that way. One such fault that I can think of right now is if C25 has failed short (or near-short).Find C25 which is a "bead" styletantalum capjust below and to the left of the piezo speaker. Probably orange, but not necessarily. Disconnect the battery from the 8060A, and use the ohms range on the Innova to measure across C25. It should measure roughly 19K ohms, which is actually the sum of the resistors and trim pots across it.

author: thared33
author_rank: Contributor
timestamp: April 02, 2018, 01:44:32 am
content: 19.9Kohms. I think my guess about the RMS chip was right. There is more green stuff on it than anywhere else. Pin 1 on the chip has it the worst, with 2 through 7 having some too, but even pins 8-14 have some. The purple cap C19 must have leaked and somehow also contaminated the top legs of it.EDIT: After taking another, very close look, C19 was so bad that the through holes on the bottom seem to have come off. The trace on the bottom going from the negative to another through hole also started to come up a bit. I'm positive that wasn't the problem originally, but it's something else that should probably be fixed.I really wanted an 8060A since they're cool and oldschool and I need one for testing stuff in my little recording studio but I probably shouldn't invest any more time or $$$ into it.

author: ModemHead
author_rank: Frequent Contributor
timestamp: April 10, 2018, 10:36:23 pm
content: thared33 sent his 8060A to me for repairs.The biggest problem was actually PCB damage from where C19 puked up its guts. After backing out the caps I found no pads and no through-hole plating for C19 at all. C24 was also missing the bottom pad and hole plating, meaning two caps in the RMS converter section were actually not connected to anything. I figured this meant there was good chance the RMS converter chip was actually good after all. But I didn't want to risk a second removal procedure so I replaced the chip with a known-working one. I patched up the board using some squares of copper tape and Kynar wire.Meter works fine now. And after installing the old RMS converter chip in another chassis, it turns out that it is indeed still functional.P.S. thared33 found the missing button under his desk, so no worries there. And for 8060A aficionados, the serial number on this unit begins with 334.

author: lowimpedance
author_rank: Super Contributor
timestamp: April 11, 2018, 12:53:44 am
content: good job , and another one saved.And ewwwww. that cap puke is truly evil !.

author: Fungus
author_rank: Super Contributor
timestamp: April 11, 2018, 08:50:47 am
content: Be afraid, 8060A owners:

author: tautech
author_rank: Super Contributor
timestamp: April 11, 2018, 09:55:40 am
content: Quote from: Fungus on April 11, 2018, 08:50:47 amWhy ?Have you never heard of a repair bodge ?You do what you need to do to fix stuff.

author: ModemHead
author_rank: Frequent Contributor
timestamp: April 11, 2018, 02:08:26 pm
content: That kind of damage doesn't occur overnight. So my best advice is:Close inspection. Any kind of crud or fuzzy stuff is bad. Dull or dry-looking solder joints are bad, especially when others are nice and shiny. Look for guilty expressions on the caps.If you're repairing a non-working unit, then re-cap it as a matter of course.For working units with early 80s date codes and/or serial numbers starting with "3", a pre-emptive re-capping is not a bad decision. I don't think the units made in the late-80s and 90s are at much risk, but that's based on my very limited experience. You know your own tech skills, so you can weigh the pros and cons of "fixing something that ain't broken."

author: thared33
author_rank: Contributor
timestamp: April 11, 2018, 10:18:10 pm
content: If I remember correctly the C19 in your other repair was the only cap that didn't leak. My meter turned out being basically the opposite - in pretty darn good condition everywhere, except my C19 was the nastiest vomit you could ever get from it. I also guess that RMS chip wasn't too affected by the green snot on it.Great work ModemHead