Author Topic: Old Fluke Multimeters  (Read 223593 times)

0 Members and 2 Guests are viewing this topic.

Offline andywander

  • Contributor
  • Posts: 5
  • Country: us
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

  • Super Contributor
  • ***
  • Posts: 4022
  • Country: us
  • Eternally curious
    • Vbe - vídeo blog eletrônico
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.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

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

  • Contributor
  • Posts: 5
  • Country: us
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.
 

Online Shock

  • Super Contributor
  • ***
  • Posts: 3336
  • Country: au
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.
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline andywander

  • Contributor
  • Posts: 5
  • Country: us
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

  • Super Contributor
  • ***
  • Posts: 4022
  • Country: us
  • Eternally curious
    • Vbe - vídeo blog eletrônico
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 »
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

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

  • Contributor
  • Posts: 5
  • Country: us
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

  • Super Contributor
  • ***
  • Posts: 4022
  • Country: us
  • Eternally curious
    • Vbe - vídeo blog eletrônico
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.

Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

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

  • Contributor
  • Posts: 5
  • Country: us
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

  • Contributor
  • Posts: 12
  • Country: us
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.
 

Online ogdento

  • Regular Contributor
  • *
  • Posts: 112
  • Country: us
Re: Old Fluke Multimeters
« Reply #785 on: Yesterday at 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
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf