Restoring / Repairing an old Fluke 8000A

[vinlove]

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.

[joeqsmith]

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

[vinlove]

Thanks for the link.  Will investigate.

[NoisyBoy]

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.

[joeqsmith]

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.

Looks 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? 

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.

If you can, post a few clear pictures of it.  Both the outside case and the inside.

[vinlove]

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.

[edavid]

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.

[NoisyBoy]

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.

[vinlove]

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.

[vinlove]

Great advice NB. Yup, will replace the capacitors, and see how it will perform.

[joeqsmith]

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. 

Great advice NB. Yup, will replace the capacitors, and see how it will perform.

I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.   

[med6753]

I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.   

Apparently 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. 

[med6753]

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.

Don'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. 

[NoisyBoy]

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.

[edavid]

10$ in USA? I see on eBay a few of 8000A are going for $40 there about, but it is not about money.

You 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.

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.

I 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 

[joeqsmith]

I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.   

Apparently 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.

No 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

[med6753]

I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.   

Apparently 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.

No 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.   

Quite simply we got there because they are the most common fail point and have the least life expectancy of most other components.

[joeqsmith]

I 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 

It 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....

[joeqsmith]

I wonder how we ever made it to the point where the first step in troubleshooting electronics is change all the capacitors.   

Apparently 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.

No 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.   

Quite simply we got there because they are the most common fail point and have the least life expectancy of most other components.

I 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.   

[med6753]

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 the real issues.

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. 

[joeqsmith]

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 the real issues.

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.

Had 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.   

[med6753]

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 the real issues.

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.

Had 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.

I 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.   

[GregDunn]

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.

[joeqsmith]

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 the real issues.

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.

Had 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.

I 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.

It'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 failure 
Used Fluke 189, a wannabe tech lost one of the switch contacts
Used Fluke 97, damage to front end and solder fracture
My bench meter & GPIB controllers, damaged ICs from lightning strike
Neighbors sound system, solder fracture
Friends calculator, solder fracture
Laser printer, bad Alum Elec (only changed one)
RF generator, bad relay
Used spectrum analyzer,  blown mixer
VNA, bad mechanical switch
Friends old service monitor, bad Alum Elec.
Old ham radio, solder fracture
My 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 IC
Electrometer, damaged op-amp IC
Old HP logic analyzer, tant cap in power supply, one bad but replaced two of them

Now, 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....

[vinlove]

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.