Old Fluke Multimeters

[Jeff eelcr]

Portable Test Instrument (PTI) in the description of the 7260A and 7261A.
Jeff 

[mqsaharan]

I'm mostly puzzled by the fact that I can't find a C19, either in the schematic, or the parts list. There are 7 electrolytic caps in my 8060A, which matches the parts list. All the silkscreen polarities seem to be correct, though I can't see the polarity or silkscreen for C16, the 1uF tant without sucking it off the board.
The build date for my meter is going to be late 1999 or early 2000 judging by the IC date codes, with the date of the PDF 2000 or later.

In 8060A, C19 is 47uF 10V capacitor, used with U2 SC77174P, Flukes custom made TRMS converter. If your meter has Fluke's TRMS converter then C19's placement is at the lower right side of the LS1, Piezo Transducer or adjacent to the pin 1 of U2. And if your meter has AD636 TRMS converter mounted on a daughter board, C19 is not required. But if you still want to know its position, it is under the lower edge of that daughter board.

[AVGresponding]

I'm mostly puzzled by the fact that I can't find a C19, either in the schematic, or the parts list. There are 7 electrolytic caps in my 8060A, which matches the parts list. All the silkscreen polarities seem to be correct, though I can't see the polarity or silkscreen for C16, the 1uF tant without sucking it off the board.
The build date for my meter is going to be late 1999 or early 2000 judging by the IC date codes, with the date of the PDF 2000 or later.

In 8060A, C19 is 47uF 10V capacitor, used with U2 SC77174P, Flukes custom made TRMS converter. If your meter has Fluke's TRMS converter then C19's placement is at the lower right side of the LS1, Piezo Transducer or adjacent to the pin 1 of U2. And if your meter has AD636 TRMS converter mounted on a daughter board, C19 is not required. But if you still want to know its position, it is under the lower edge of that daughter board.

Ah, mine has the AD636 daughter board. Thankyou for explaining that.

[BeBuLamar]

Make me want to buy a 8060a to go with my Simpson 260.

[mansaxel]

Make me want to buy a 8060a to go with my Simpson 260.

You'll find them on the 'Bay for about $100 from Israel.  My personal record is 150 SEK, for one that turned out to be in excellent shape. Before that I'd bought one from USA for about $75, which was OK. But not fantastic.

A re-cap of course is important. All info is here and in the blog post from Mr Modemhead, which is found both upthread and as a courtesy here.
 

[rsjsouza]

Make me want to buy a 8060a to go with my Simpson 260.

You'll find them on the 'Bay for about $100 from Israel.  My personal record is 150 SEK, for one that turned out to be in excellent shape. Before that I'd bought one from USA for about $75, which was OK. But not fantastic.

Holey moley! Your post prompted me to look at eBay for 8060A and the prices are in the hundreds of dollars from insane sellers! Sure the actually sold items are much lower priced (US, though).

[Fungus]

Sure the actually sold items are much lower priced (US, though).

They'll be much lower in the USA.

I've got a spare one here in Spain. If anybody's interested, PM me.

[rodcastler]

In my case even though none of the usual electrolytics showed leakage, there was one point showing evident corrosion, and that was under C37.

It's a small blue 0.01uF ceramic that was leaking after breaking (there was a visible crack, and one of the legs fell off when I removed the part). The photo shows the fix with an orange cap.
I'm fairly confident this meter was never plugged to an external power supply, so I can only assume this cap gave up out of age, while under 9v from the battery

You may want to inspect C37 for corrosion just in case. The meter will most likely function correctly if this cap fails open.

[rsjsouza]

Interesting. Ceramic disc capacitors have solid dielectrics.
Since the corrosion was close to the battery wire, I (and others) have seen leaky battery corrosion migrate through the wire from the contacts to the PCB. Perhaps this was indication of such past event?

Of course it could also be simply contamination or fluid ingress into the housing.

[rodcastler]

You must be right.
Although there are no signs of corrosion anywhere else: the battery connector and wires are intact. Corrosion was present on the board, in the area but now I can't remember exactly if it was right under the cap or right between the wires.

My first thoughts were even around some sort of corrosion out of condensation, considering it was a ceramic cap, but then when I noticed that the capacitor had cracked, I began to distrust the ceramic nature of the cap. You brought a good point. I'm not sure what could have happened.

[rsjsouza]

Interesting that everything else was intact and, looking at the wire, it seems indeed original. If you have bought this used, there is a chance it might have been replaced before without your knowledge. Well, that or the capacitor itself was a bad part mounted in factory where a minute corrosion was present and became noticeable only after decades. At this point all is a guess. 

Regarding the cracked capacitor, I also have seen this happen when corrosion in the leads is severe: the leads become so corroded that it weakened the ceramic and it cracked at the slightest touch. But in the cases I have seen, the corrosion was clearly an outside job (humidity, electrolytes, etc.)

Well, it is good that you found the issue before extensive PCB damage happened. These meters are sturdy as they come.

[Fungus]

Now I'm all worried about mine again.

I still haven't got around to recapping them.

[cocosteel]

Hi everyone,
I think I have found here the greatest resources for servicing vintage Fluke DMMs, thank thanks to all contributors.
I have read almost the whole topic regarding the 8060a model and now I would go for a re-cap of my mine, as per DrTaylor's valued explanations here as well as Mr.ModemHead's blog.

I'll order soon all replacement capacitors according to the list published by DrTaylor's some years ago : https://www.eevblog.com/forum/testgear/old-fluke-multimeters/?action=dlattach;attach=344836;image
All is great for all polymer capacitors, but unfortunately for recapping C36, the advised reference is from the Nichicon UTT family which is now obsolete.

Even if major retailers still have some stock to deplete, I wonder if it would be a good idea to find a replacement reference in current production. Could you help me to choose it, please ?
Aluminium electrolytic ; 22 µF/16V ; 105°C 5000hr ; Ø5mmx8mm for the main characterics ... but I'm just unable to think about others specs like ripple current, impedance etc.

The small UTT form factor seems difficult to meet, and the Nichicon's advised subsitute 63YXF22MEFCT16.3X11 is oversized.
Many thanks for your help.

[scopeman]

How about Panasonic's OSCON Organic Aluminum Caps. Very low ESR. I have used  them in high volume production with very good results. No failures or issues in 10 years of service in an industrial environment.

Sam
W3OHM

[rsjsouza]

If you want to stay on Polymer, I can attest the Panasonic OSCON capacitors are good as well, although it is hard to find the exact diameter - all 22µF I found are 6,3mm (Panasonic SEPF), as well as from Kemet A758 and Wurth (also good brands)

If diameter is the hard requirement, Kemet A759 meets the 5mm, although it is much taller.

[Fungus]

Aluminium electrolytic ; 22 µF/16V ; 105°C 5000hr ; Ø5mmx8mm for the main characterics ... but I'm just unable to think about others specs like ripple current, impedance etc.

I think any big-brand capacitor today will be better than what was in it originally.

[mansaxel]

I recently won some old Fluke manuals, for the 8022A and the 8060A. For next-to-nothing. The 8060A also included the quick-guide, a laminated folder, in swedish! 

In the interest of completeness, I'm including a scan of it below.

The manuals are the full manual, with schematics and all. I'll try to publish them too.

[drtaylor]

Hi to all 8060 fans! I have recently completed restoring and recapping 15 8060A Multimeters. They all work fine. However, I do not have an AC Calibrator that is capable of calibrating the AC function. I've tried to do transfer calibrations using a function generator comparing to some of my higher resolution DMMs. But not ideal. I do not know anyone at Fluke anymore that would help, all my former colleagues have either retired or moved on. I have looked at calibration services in the Seattle area, and to calibrate using a commercial service would cost more than each 8060 is worth. I do have an old Fluke AC Calibrator, but it needs to be restored.

Does anyone within driving distance of Seattle have a calibrator they might allow me to use in exchange for a reasonable sum and/or a signed 8060 as well? If I can't get access to a decent calibrator, I guess the restoration of my Fluke 5200A will have to be my next project. But, if I remember correctly, to calibrate the 5200A requires some exotic equipment too, so I may be screwed.

[bdunham7]

If you don't need any sort of traceability, you can ship them to me and I'll be happy to set them up.  An 8060A restored and signed by one of its designers would be more than adequate compensation for me.

I don't have anything fancy, but I use a restored 5100B, which is what I believe Fluke would likely have used to calibrate these originally.  I use a 6.5-digit DMM (8846A) as both a parallel reference and to calibrate/verify the 5100B, so the calibration accuracy is limited to that, but that is probably more than adequate for the 8060A.

I've repaired/restored a 5200A and that is not a trivial job.  I'm not sure that all of the items on its calibration equipment list are readily available in good condition anymore and modern alternatives are frighteningly expensive.

[The Doktor]

Is there any problem re-capping an 8060 with tantalum caps?

[drtaylor]

As far as I know, you could use all tantalums in the 8060. I don't think it will improve anything except perhaps in the charge pump. Tantalums are less forgiving for reverse voltage, so be very careful with polarity. I vaguely recall that a small amount of reverse voltage is possible at C19, but I could be wrong. As long as they are of adequate voltage, and they fit the pads, have at it. I built the original prototypes with a lot of tantalums and it worked fine. Wasn't worth the cost, except unless you expected to be using the 8060 30 years later. Who knew that would happen? I always use at least 5000 hr, 105degC rated Aluminums. If you put those in, the 8060 could easily last another 30 years.

[helius]

How about Panasonic's OSCON Organic Aluminum Caps. Very low ESR. I have used  them in high volume production with very good results. No failures or issues in 10 years of service in an industrial environment.

Solid polymer electrolytics have high leakage. Not ideal for measurement instruments.

[precaud]

Hi to all 8060 fans! I have recently completed restoring and recapping 15 8060A Multimeters

A year or so ago you said you had some spare MAC IC's tucked away somewhere. Did you ever find them? I still have a couple 8060A's with bad MACs and could use a couple.

[drtaylor]

How about Panasonic's OSCON Organic Aluminum Caps. Very low ESR. I have used  them in high volume production with very good results. No failures or issues in 10 years of service in an industrial environment.

Solid polymer electrolytics have high leakage. Not ideal for measurement instruments.

Solid Polymer Capacitors actually perform better in most Electrolytic locations in the 8060A. Leakage does not come into play when the caps are being used in power supply filters and the charge pump. The charge pump in the 8060 performs better with polymers. The only place I would say that the leakage could possibly be an issue would be in the TRMS converter. Note, I'm referring to the original TRMS circuit designed by Fluke, not the later ones using an Analog devices chip. The AC output filter C17 is indeed in the signal path, but with a source impedance of less than 20k, the leakage would not cause a discernible error. C18 and C19 could also be affected by leakage. Also realize that Polymer Electrolytics leakage is measured at full voltage, and high temperature. I don't think you'd have an issue. That being said, low leakage standard aluminum electrolytics work fine in all the locations in the 8060A. I'd use polymers in the charge pump circuit as this does show some improvement at the noise floor. Still compared to the caps we had available in the early 1980s, current caps are superior, as long as you pick a reputable manufacturer. I tend to specify 105deg (or higher) 5000hr rated caps for reliability. So, while I do agree that Polymer Electrolytics should be avoided in the signal path of high resolution measurement equipment, you cannot make a blanket statement that they should be avoided. Just don't use them as a filter in a circuit with a high value source impedance.

[caall99]

Hey all! Great thread and thank you all for the great contributions. I have recently bought 10 different 8000 series handhelds, and have a couple 8060s i am looking to recap. the 8060a multimeters I have are newer PCB revisions and all the test points show they are A-OK. Also, there are no signs of leaking electrolytic fluid, but I intend to replace all the caps either way. Unfortunately, MrModemHead's capacitor purchase list is now obsolete, as many of the components are no longer being manufactured. drtaylor, and co., is there a new purchase list? I am having trouble finding low profile capacitors, branded Rubycon or Nichicon that are actually in stock. Please let me know!