Author Topic: Old Fluke Multimeters  (Read 230223 times)

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Offline andywander

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Re: Old Fluke Multimeters
« Reply #775 on: September 19, 2020, 02:58:27 pm »
I have read through this entire thread, and learned a lot about the 8060A, and other Fluke meters.

I have 3 of the 8060A meters, and use them all the time.

One of them needs to have the Zebra Strips cleaned, as the display is getting flaky.

2 of them have no-name electrolytic caps, which I plan on replacing.

The third meter has Nichicon-branded electrolytics. Am I correct that these should NOT require replacement?
 

Offline rsjsouza

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Re: Old Fluke Multimeters
« Reply #776 on: September 19, 2020, 04:05:20 pm »
Nichicon capacitors can leak as well, depending on age and usage conditions. I would inspect them and see if any is leaking or swollen.
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Offline andywander

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Re: Old Fluke Multimeters
« Reply #777 on: September 19, 2020, 04:21:48 pm »
Thanks for the reply.

From what I read, the only real way to inspect the caps is to remove them from the board and look at the "bung".

If that's the case, I might as well replace them while I have them out, I guess.
 

Offline Shock

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Re: Old Fluke Multimeters
« Reply #778 on: September 19, 2020, 08:52:20 pm »
It makes sense to replace them so they are identical. It's a good idea to buy a few spares when ordering components anyway.
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Offline andywander

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Re: Old Fluke Multimeters
« Reply #779 on: September 20, 2020, 04:52:46 am »
Well, I replaced all of the electrolytic caps on the oldest meter.

I noticed that the circuit board has marking for "+ on most of the capacitors, and the marking for C19 showed that the pin closest to the display is "+". However, the cap I removed had it's negative pin installed closest to the display.

I checked the other 2 8060As I have here, and they both had the cap installed negative pin closest to the display.

I didn't see reference to this in any of the writeups I have read about recapping these meters, and from what I can make out in the photos in mrmodemhead's blog posts, he installed C19 the way the board is labelled, positive pin closest to display.

I see no sign that these 3 meters have been molested in the past, one has a SN beginning with a 4, one begins with a 5, and the newest one begins with a 6.

From the dates on the chips, they look like they were built starting around 1987, and ending around 1995.

Has anyone seen this? Or am I on drugs?

Andy
 

Offline rsjsouza

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Re: Old Fluke Multimeters
« Reply #780 on: September 20, 2020, 01:45:26 pm »
Photos would help.

I have a number of old (1970s-1980s era) electrolytic capacitors with marks on the positive terminal instead. Perhaps that could explain this?

I suspect you are not confusing tantalum (which marks positive) with electrolytic (which marks negative), but I have to ask. :)
« Last Edit: September 20, 2020, 03:02:19 pm by rsjsouza »
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline andywander

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Re: Old Fluke Multimeters
« Reply #781 on: September 20, 2020, 05:50:06 pm »
Yes, you're right about the pictures. Here are some:

EDIT: my pictures were too large, and didn't upload. Here they are now, though!

This is SN 4220786; this meter was purchased on ebay this year(2020), and from the chip date codes I think it was new in 1987 or so.  This is the one that I already removed C19 from, but it had been installed with the negative post toward the display. You can see the "+" on the ckt board for C19. I also laid the old C19 on top of the buzzer.
[attach=1]

Here are some photos of SN 5135102, this meter was inherited from my Dad, around 1999. From the chip dates, I think this was new in around 1990 or 1991. The photos are an overall shot of the board, and then a closeup of the C19 area. It looks pretty clear that the C19 negative is installed toward the display
[attach=2]
[attach=3]

This is my 3rd 8060A. It is SN 6520032, and I purchased this unit new in the mid 1990s. Chip date codes make me think it was produced in 1995 or so. This one also has C19 installed with negative terminal toward the display.
[attach=4]
[attach=5]

This is a shot from Mrmodemhead's blog, and appears to show C19 with the negative terminal away from the display:
http://mrmodemhead.com/blog/wp-content/gallery/f8060a_01/IBM8060A_013.JPG

And finally, here is the schematic, which shows the "+" side of C19 tied to Pin 6 of U2. I confirmed that on the board itself, the terminal labeled "+" goes directly to U2 Pin 6.
[attach=6]

So, what I can't understand is how 3 different meters, produced over a span of 8 or 9 years, could have this capacitor installed backwards, and still work just fine!

Unless the capacitor, in that location, does not see any DC voltage? I'm not knowledgeable enough in circuit analysis to be able to tell...
« Last Edit: September 20, 2020, 06:02:38 pm by andywander »
 

Offline rsjsouza

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Re: Old Fluke Multimeters
« Reply #782 on: September 20, 2020, 07:01:42 pm »
Ok, so I cracked open my two Flukes:

The 8060A (serial number 4245166) has a Siemens orange capacitor (!) that I replaced a few years ago - either I had nothing better on hand or had a mental fart. Negative points to the display, therefore I suspect I followed my golden rule to never trust the silk screen (I have been bitten before).

The 8062A (serial number 4210192) has the original yellow capacitor. Negative also points to the display. I will replace and, in the light of all this, I will probably keep the assembled polarity instead of the silk/schematics one. Not only there is a chance the bias voltage is too small to make a difference, but the weight of 30, 35 years of continuous operation without fail are enough for me to make a decision.

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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline andywander

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Re: Old Fluke Multimeters
« Reply #783 on: September 20, 2020, 08:01:46 pm »
I'm going to install them "backwards" (negative towards display; negative to Pin6 of U2) as well.

Thanks for looking inside your meters!
 

Offline Raindog

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Re: Old Fluke Multimeters
« Reply #784 on: September 20, 2020, 10:10:00 pm »
Ah yes, good old Fluke meters. I have the 8060A (20+ years) that I still use to this day and the 8050A bench version.
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Offline ogdento

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Re: Old Fluke Multimeters
« Reply #785 on: September 21, 2020, 07:11:58 pm »
I cracked open two 8060s and they're both different ;) 

The newer one with Rev J board has '91 date codes and opposes the schematic/silkscreen... the + is not visible on the silkscreen (might be under?), the cap's negative is toward the display and connects to RMS pin 6.
[attach=1]

The older one (an IBM "version") with Rev F board has '82 date codes and matches the schematic/silkscreen... the + is visible on the silkscreen, the cap's positive is toward the display and connects to RMS pin 6.
[attach=2]

Here are the backs of both (notice the differences by the converter)
[attach=3]

**I also looked at 4 or 5 other boards... the Rev F and H boards matched the schematic/silkscreen while the Ref J boards did not
 
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Offline precaud

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Re: Old Fluke Multimeters
« Reply #786 on: September 24, 2020, 10:19:13 pm »
Are the 80xx 3.5-digit LCD's interchangeable between models?

I have an 8012A that needs a new LCD, and a couple 8022B's I could steal one from.
 

Offline bd139

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Re: Old Fluke Multimeters
« Reply #787 on: September 24, 2020, 10:44:11 pm »
Think they are the same. I’ve replaced a few of both with different modules before.

See the following if you want to do it the hard way https://www.eevblog.com/forum/testgear/fluke-8010a-mains-only-conversion-and-display-replacement/

(This works for the handhelds as well)
 

Offline precaud

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Re: Old Fluke Multimeters
« Reply #788 on: September 24, 2020, 10:58:59 pm »
Think they are the same. I’ve replaced a few of both with different modules before.

Hmmm. I just downloaded the manuals, they have different part numbers. 8012A = 698381,  8022B = 504324

Quote
See the following if you want to do it the hard way https://www.eevblog.com/forum/testgear/fluke-8010a-mains-only-conversion-and-display-replacement/

Yes, I read that, very interesting. Hope I can find an easier solution  :)
The 8012A is getting bench space for its low ohms mode.
« Last Edit: September 25, 2020, 12:11:09 pm by precaud »
 

Offline precaud

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Re: Old Fluke Multimeters
« Reply #789 on: September 24, 2020, 11:38:42 pm »
I pulled them and unfortunately they're not the same size.

But the 698381 LCD is available on eBay for 12 bucks, so I ordered one:
https://www.ebay.com/itm/Fluke-LCD-3-5-Digit-Direct-Drive-698381-Display-For-Multimeter-/124265554466
 

Offline bd139

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Re: Old Fluke Multimeters
« Reply #790 on: September 25, 2020, 06:24:21 am »
Bah that’s annoying. At least there are spares available at the moment.

About two years ago I spoke to a Chinese company about getting some new ones made up. Small run (200 pieces) was cost prohibitive. Worked out at 22 GBP a display.
 

Offline precaud

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Re: Old Fluke Multimeters
« Reply #791 on: September 25, 2020, 01:24:03 pm »
Yeah, that's pricey, indeed. And 200 pieces would take quite a while to move.

At first glance it looked like the seller I bought from had multiples of the 698381, but it looks like I got the last one.

Is there a trick to reinstalling the LCD? I was afraid it would break when I put it back in yesterday, getting the plastic frame's clips over the glass. Didn't impress me as a procedure the factory would use to install them.
 

Offline bd139

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Re: Old Fluke Multimeters
« Reply #792 on: September 25, 2020, 04:06:30 pm »
It's not great I agree. I've never broken one (yet  :-DD)
 

Offline AVGresponding

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Re: Old Fluke Multimeters
« Reply #793 on: September 25, 2020, 05:37:07 pm »
Maybe thoroughly warm the plastic on a radiator beforehand, to reduce its brittleness?
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Offline precaud

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Re: Old Fluke Multimeters
« Reply #794 on: September 25, 2020, 05:52:19 pm »
Yeah, I did warm it up with a heat gun for just that reason. I don't have a replacement! But I still can not believe this is what they did on the assembly line.
 

Online mansaxel

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Re: Old Fluke Multimeters
« Reply #795 on: September 25, 2020, 07:00:10 pm »
Perhaps the plastic was less brittle back then.

Offline AVGresponding

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Re: Old Fluke Multimeters
« Reply #796 on: September 26, 2020, 09:25:32 am »
Perhaps the plastic was less brittle back then.

It would have been, for sure. Plasticiser tends to leach out and/or degrade with age.
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Offline rsjsouza

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Re: Old Fluke Multimeters
« Reply #797 on: September 26, 2020, 10:01:57 am »
Yes, that is my experience as well. Certain types of plastic and their exposure to UV/Sunlight and other elements degrade it.

It is not uncommon to open an old equipment with these plastic tabs holding its housing together and break several of them in the process applying minimal force.
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Offline precaud

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Re: Old Fluke Multimeters
« Reply #798 on: October 01, 2020, 10:12:10 pm »
The new LCD install went well. I did have to put a thin plastic wedge between the plastic clip and the "hood" that holds the lcd, to press the zebra strip against the glass and get all digits to appear.

One thing I notice about this 8012A compared to other milliOhm-resolution meters I have is, the readings on the last digit are more stable. I think this is because it boosts the output current to 10mA when in low ohms mode. I like it.
 
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Offline 5618

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Re: Old Fluke Multimeters
« Reply #799 on: October 14, 2020, 07:24:37 am »
Hi. Here’s an interesting 8060A with a clear case. Initial checks with a fresh battery showed missing LCD segments. I removed the lens, gave the LCD some wiggling, and reinstalled the lens after cleaning it. That brought the whole LCD to life. It looks like A-D isn’t functional yet. No volts or ohms show, only OL. Ratio self test doesn’t change the display from OL. Switch decoding test checks out fine. Hz changes display to 0.00. Continuity and REL show up in display so all functions look like they go through the motions. Fuses, R1, and R2 are good. Closer inspection looks like C36 has leaked a bit. Next step is get caps and replace them. That’s as far as I got tonight. Old battery clip in pic isn’t from this meter.

« Last Edit: October 14, 2020, 07:58:59 am by 5618 »
 
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