Restoring / Repairing an old Fluke 8000A - Page 1
Forum section: electronics / testgear

author: vinlove
author_rank: Frequent Contributor
timestamp: January 11, 2020, 01:03:19 am
content: I just got an old vintage 8000A, and it is in pretty poor condition. It looks like it had real hard life, and then stored in rough environment for long time.When powered on, it has following problems.1. Display comes on, but numbers just change itself all day long. It is not responding to the probes. Sometimes it tries to, but soon it goes back to meaningless random number display. When different modes are selected, it doesn't respond on the LED display, again it just keeps displaying its own random numbers or does countdowns or count ups.2. The buttons get sticky, and when DCV is selected, Kohm must pops out, but i doesn't. It just get stuck in there, so its like 2x buttons are selected.This meter would be real cool if it works properly, because it can read up to 1200ACV. Not many modern DMMs can do that. And it is darn useful to work on the tube amp or tube gears with HV.What should be done first? I mean is full recapping necessary? I just want to get it working with reasonable accuracy.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 11, 2020, 02:06:08 am
content: Besides getting the manual, grabbing the scope and another meter and start plugging away, hard to say. The following may be of interest if you ever get it working:https://www.eevblog.com/forum/testgear/strange-behavior-while-calibrating-a-fluke-8000a/msg2384277/#msg2384277

author: vinlove
author_rank: Frequent Contributor
timestamp: January 11, 2020, 02:32:36 pm
content: Thanks for the link. Will investigate.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: January 11, 2020, 04:36:44 pm
content: That was my meter in that thread, Joe has always been tremendous help and a wealth of knowledge on the 8000A. I am always grateful for his help on the meter.In my case, the meter was working, I just tried to calibrate it and improve its accuracy. In your case, you need to first restore it to a working state, go download the owner manual, start with the troubleshooting guide in Table 4-4 and see what you find. There are a lot of mechanical switch in the 8000A, if it was not stored correctly, you could have some contact corrosion issues as well.Good luck, mine has been extremely reliable, but I would always be cautious in using such an old meter in high voltage work. Mine never test anything above line voltage.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 11, 2020, 05:29:16 pm
content: Quote from: NoisyBoy on January 11, 2020, 04:36:44 pmLooks like windsmurf fell into one of the forum's political traps.Seems we loose a lot of good members in these shit shows but at the same time they seem to be at least as popular on this site as electronics.Did you ever find/start working on the second one?Quote from: vinlove on January 11, 2020, 01:03:19 amIf you can, post a few clear pictures of it. Both the outside case and the inside.

author: vinlove
author_rank: Frequent Contributor
timestamp: January 11, 2020, 06:35:06 pm
content: Yes, when I get around to opening the 8000A, I shall take some photos and post them here.It definitely has corrosion problems on each buttons on front. I shall give them some squirt of servisol or electronic contact cleaners and start from there.If it makes difference and start working, then I will just use it as is.But if not, maybe look into all the caps for their condition, and if need be, replace them.It tries to work sometimes, then it goes into displaying random numbers.At one point when I was trying to do some tests with it, I was stunned that it read used PP9 battery voltage with spot on accuracy, and also read a dummy load giving 53 ohms which is also accurate.Then it went into unresponsive mode on the probes flickering 19.99 all day.I think it had been stored in cold damp area for long time for so long, all the caps lost charges, and also got hardened. When it is left plugged into the mains, it seemed trying to recharge all the caps, but finding it difficult.

author: edavid
author_rank: Super Contributor
timestamp: January 11, 2020, 06:59:32 pm
content: When you say "caps", are you actually talking about NiCd batteries?The battery version of the 8000A has to have batteries installed to function. They don't have to hold a charge, but they do have to be healthy enough to act as a combination of a capacitor and a zener diode, and of course they have to make contact with the holder contacts.P.S. I don't know where you are, but in the US this is a $10 meter, so not really worth any heroics.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: January 11, 2020, 10:47:40 pm
content: Hey Joe, good to hear from you, happy New Year. No, I have not dugged up the second 8000A yet, I am moving everything from my storage to my hobby building once they finished building it this summer, so I will be able to tackle it.edavid, I agree with you. The meter is so cheap and plentiful, it is not worth fixing unless it is for personal enjoyment.vinlove, while it may be related to the capacitor, and it is not a bad idea to change out-of-spec caps, I would suggest follow the troubleshooting guide while the meter is in failed mode. It may help you to pinpoint the cause for failure.Good luck.

author: vinlove
author_rank: Frequent Contributor
timestamp: January 12, 2020, 11:39:25 am
content: edavid, no, it doesn't.Cap. means capacitor. My 8000A is a mains version. No nicads.10$ in USA? I see on eBay a few of 8000A are going for $40 there about, but it is not about money. I like the 8000A, and was wanting it for many years. I like the LED display in red colour. And this is a historic meter, which had been in many electronics magazines and used by millions of electronic enthusiasts. It means something to me.Plus, when meter or set is not working properly, and no matter what the price or monetary value is, if I worked and serviced on it, and when it works again properly, it gives good feeling. That is what all is about.

author: vinlove
author_rank: Frequent Contributor
timestamp: January 12, 2020, 11:41:10 am
content: Great advice NB. Yup, will replace the capacitors, and see how it will perform.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 03:57:23 pm
content: Quote from: NoisyBoy on January 11, 2020, 10:47:40 pmQuote from: vinlove on January 12, 2020, 11:41:10 amI wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.

author: med6753
author_rank: Super Contributor
timestamp: January 12, 2020, 05:19:12 pm
content: Quote from: joeqsmith on January 12, 2020, 03:57:23 pmApparently you have not attempted to restore vintage vacuum tube equipment. You can be assured, with 100% certainty, that all the wax tubular and electrolytic capacitors will be leaky and require replacement. SOP is to replace before the first power up is even attempted. The only general exception to this rule is vintage vacuum tube Tek and HP equipment. They tended to use much higher quality capacitors which last near indefinitely.When it comes to vintage Flukes such as the 8000A, 8600A, 8800A, etc my personal experience is that at least one electrolytic capacitor in the power supply is shorted. So it makes perfect sense to replace all of them as insurance for trouble free operation.I could go on concerning beaded tantalums in Tek equipment from the 1970's thru 1990's but I think you get my point.

author: med6753
author_rank: Super Contributor
timestamp: January 12, 2020, 05:27:11 pm
content: Quote from: vinlove on January 12, 2020, 11:39:25 amDon't let the nay sayers discourage you. The 8000A is a perfectly serviceable 3.5 digit DMM with good accuracy when fixed up and calibrated.And I'm partial to ruby red LED's myself.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: January 12, 2020, 06:02:56 pm
content: I bought two units years ago for the same nostalgic reason. While I was in undergrad, the 8000A series were backup meters in the lab, everyone was using the newer HP meters. I rarely needed the high precision of the HP, so I would grab a 8000A as my personal meter that I didn’t have to share with others and could have it hooked up to my projects until the lab was over.As Joe had mentioned, I got a 8000A that is main only, and one is the Ni-Cd model. The Ni-Cd model is in storage that I cannot locate, but the main model was fully restored and calibrated. It is not precise, but accurate and reliable. I enjoy the pride to see it working fully within spec with Joe’s guidance in the calibration. Its red LED and those big, hard-to-press range switches bring back a lot of treasured memory.Its biggest drawback is the lack of auto ranging, if I have multiple test points with varying voltages, due to its lower precision, I often had to change range constantly. But beyond that, it is fully serviceable in the lower voltage work that I do. It is not my primary meter, that goes to the Keysights in the hobby lab, but a great “toy” meter.

author: edavid
author_rank: Super Contributor
timestamp: January 12, 2020, 06:10:56 pm
content: Quote from: vinlove on January 12, 2020, 11:39:25 amYou have to look at sold listings. Anyway, people don't bother listing them on eBay, since they are worth so little. At hamfests etc. they are $10 or less.QuoteI like it too (I have 5 of them), but if I had one as trashed as yours seems to be, I would just buy another one

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 06:36:56 pm
content: Quote from: med6753 on January 12, 2020, 05:19:12 pmNo doubt that changing the caps is now commonly the first thing many do. I wonder how we got to this was what I was asking.Not to hijack OP's thread, but we still use this old radio on a regular basis.https://www.eevblog.com/forum/repair/old-console-radio-repair/msg1455644/#msg1455644

author: med6753
author_rank: Super Contributor
timestamp: January 12, 2020, 06:42:25 pm
content: Quote from: joeqsmith on January 12, 2020, 06:36:56 pmQuite simply we got there because they are the most common fail point and have the least life expectancy of most other components.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 06:47:41 pm
content: Quote from: edavid on January 12, 2020, 06:10:56 pmIt does sound pretty bad which is why I wondered what it looked like.OP, if you do decide to find another one in better condition, I strongly suggest you pull some of the parts from this one. Those custom IC's, LEDs....

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 06:51:19 pm
content: Quote from: med6753 on January 12, 2020, 06:42:25 pmI can't imagine wasting a bunch of time changing every cap in a product before hunting down the root problem. Maybe the lack of troubleshooting skills drove us there.

author: med6753
author_rank: Super Contributor
timestamp: January 12, 2020, 07:15:54 pm
content: It's not a time waster. It's a time saver. Why troubleshoot the obvious? And why risk damaging other components if you have shorted capacitors. Sorry, but I'm in the opposite camp...it's smart troubleshooting. Then you'll be able to go after therealissues.And in ref to your vintage radio....most likely has wide component tolerances. Not unusual in consumer gear. But I'll bet if you DID recap it the performance would improve.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 07:20:09 pm
content: Quote from: med6753 on January 12, 2020, 07:15:54 pmHad you taken the time to read it, I did have to recap it eventually. It's very possible that the lack of reading and education is what drove us to swapping parts as a way of troubleshooting.

author: med6753
author_rank: Super Contributor
timestamp: January 12, 2020, 07:44:02 pm
content: Quote from: joeqsmith on January 12, 2020, 07:20:09 pmI will admit I did not read the entire thread. All I've tried to present is an opposing point of view. But apparently you want to resort to snide remarks and sarcasm. As far as I am concerned this debate is done.

author: GregDunn
author_rank: Frequent Contributor
timestamp: January 12, 2020, 08:10:35 pm
content: I had both an 8800 and an 8600 which I bought online and they exhibited semi-random displays but when changing modes would occasionally do something sensible for a few moments before becoming chaotic again. One step I'd definitely try before pulling out the soldering iron is to put some Deoxit into the mode selector switch contacts and exercise them all vigorously for a minute or two. Often bad contacts will cause extreme and puzzling behavior all by itself. Cleaning them at least ensured the meter was in a consistent state for further troubleshooting and prevented me from chasing down nonexistent gremlins. IIRC one of the meters required no further action - the other one ended up having a defective IC in the regulator circuit.I also "fixed" a Keithley 197a the same way. If a meter has sat for months or years, oxidation is often rampant.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 12, 2020, 08:57:43 pm
content: Quote from: med6753 on January 12, 2020, 07:44:02 pmIt's not a snide remark. I believe our education when it comes to technology and science is suffering and in place of it, we get tales. I am not a service tech and don't do a lot of repairs. Of the last few things I repaired at home,Several of my own power supplies, always a transistor or diode failureUsed Fluke 189, a wannabe tech lost one of the switch contactsUsed Fluke 97, damage to front end and solder fractureMy bench meter & GPIB controllers, damaged ICs from lightning strikeNeighbors sound system, solder fractureFriends calculator, solder fractureLaser printer, bad Alum Elec (only changed one)RF generator, bad relayUsed spectrum analyzer, blown mixerVNA, bad mechanical switchFriends old service monitor, bad Alum Elec.Old ham radio, solder fractureMy old LeCroy 64xi DSO has been repaired at some point and that area appears to be a problem. Reseating the connectors solved it.I have an old Tek TR current clamp from the 60's that was in very poor condition that required several matched transistors but no caps....RLC meter, damage synthesizer ICElectrometer, damaged op-amp ICOld HP logic analyzer, tant cap in power supply, one bad but replaced two of themNow, my old LeCroy DSO has had several tants fail. I would guess I have changed 10 or so over the years. Just not much of a trend really. I would have done more harm than good recapping these entire systems.If anything I would say my trend is toward mechanical failures. Solder joints, relay, switch.. Besides the people wanting to replace all their caps, the other common repair I see posted a fair amount is where people will reflow every connection.****Forgot a few recent ones....

author: vinlove
author_rank: Frequent Contributor
timestamp: January 13, 2020, 09:03:10 am
content: Fluke 8000a is not that easy to buy in here. It is kind of a rare gear being the 1980s product.It wasn't that cheap either. One is enough for me, unless I went out and happen to bump into them for impossible to resist price or free, I wouldnt intentionally keep buying them just because I like it.Plus I have many other DMMs mostly cheap but recent ones working well.I just wanted something sits on the bench and on all the time, so quickly measure volts and ohms on fly instead of opening the draw, pulling out the handheld dmms.The 8000a already looks cool on my bench with the red display. It worked better yesterday after having been switched on for a few days. DCV reading is good. Then when it is changed to ACV or ohms, it goes unreponsive to the probes.Need to leave it on for a few minutes and switch off and on start again, then it works again.I too, repaired a few gears recently, mostly on the old antenna tuners non working, and when I troubleshooted, it was usually dry solder joints, loose connection somewhere. Just resoldered them, they worked.Also repaired another old bench DMM called Black Star 3225. It was dead on arrival. When opened up, there were fuses one at the back of the unit, one inside the unit. The inside fuse was blown. Replaced it and worked. Easy fix. But this thing needs serious calibration. Ohms reading works fine but volt reading way way out of tune.Recapping is a painful work because it takes time and money. But most of the time it works well after.Once I got this old tube radiogram from 1940s size of a dinning table. When powered on, it made puffing noise and banging noise crackling badly. I replaced about 30 caps and dozens of resistors, took a few weeks for the job. It worked perfect after that. And that was the only way it needed to work perfect.

author: Deccatech
author_rank: Newbie
timestamp: February 25, 2022, 12:54:05 pm
content: I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.A great sentiment, refreshing to read on the web! My very best wishes to you and all who diagnose...

author: Jordanch68
author_rank: Newbie
timestamp: April 11, 2022, 06:19:48 am
content: Hello, I just thought I'd add my experience with three of these meters I've been working on since this post came up in a Google search.1. Download a free PDF of the manual as it has the service info as well.2. Replace the three large caps in the power supply section. I went with Vishay blues from Mouser. Note their cost will likely exceed the value of the meter but it's to be expected.3. I've had some success finding the IC's via the Fluke part number in the manual rather than going on what's printed on the IC. One had a missing U4 and I was able to get it via the Fluke part number.4. Erratic display or button selection issues. Clean each switch. I used Rem Oil in a spray can. Set the unit on it's face. There's a square hole in the back of each switch, give each switch a 2 second spray of Rem Oil there. Once with the switch forward and once when pushed in. Use a short burst of compressed air on each there afterwards and prop it on a front corner to let excess oil drain away. Then cycle each switch 10 times to verify full range of motion.I fixed all three of these "non-working" EBay purchases this way. Just 3 caps and a switch cleaning. In my testing all three match their measured values.Good luck keeping yours going. The only thing I'm looking for are the LED modules. The part number isn't in the manual but in the unit it's :Q2546310Thanks,Chris

author: staticx57
author_rank: Newbie
timestamp: September 07, 2022, 06:08:01 pm
content: Just want to add a data point, I bought one off of ebay that was reported with an erratic display. Spraying contact cleaner in the switches from the back seems to fix that behavior.