Author Topic: A Fluke 77 made on a Friday afternoon !.  (Read 4814 times)

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Offline lowimpedanceTopic starter

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A Fluke 77 made on a Friday afternoon !.
« on: September 15, 2015, 05:48:12 am »
 Purchased an old Fluke 77 for sentimental reasons through the usual online 'place'. Listed as tested and working, ie showed a pic connected to a 9 volt battery  ::).
Anyway of course it did not function normaly when received so opening up showed some horrible gunk around the input jacks and some corrsion. A good IPA clean or two later and some deoxit on the input terminals and all was good again for the old timer.
 BUT while it was appart I noticed some rather unusual component placement done at manufacture  :D. See the pics. for the best explanation.
Much comment is made about poor PCB assembly of products and even other upmarket DMMs in the past, and here is a pretty good example of one slipping through visual QC all those years ago.
 AND has it mattered since then for this unit, not one bit and after the cleanup it was still in spec. no tweak needed and back in service.  :-DMM

note: 10V ref and 87V verified at work, so trust me the 77 was in spec.  ;)
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline retiredcaps

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #1 on: September 15, 2015, 05:55:38 am »
BUT while it was appart I noticed some rather unusual component placement done at manufacture  :D. See the pics. for the best explanation.
Thanks for sharing the picture.
 

Offline ModemHead

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #2 on: September 15, 2015, 12:17:02 pm »
Oops.  Looks a bit starved for solder as well, I don't see any fillets.
 

Offline oldway

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #3 on: September 15, 2015, 12:59:29 pm »
Excuse me, but I find it necessary to have the particularly twisted mind to come and to do quality control on a meter which worked perfectly for over 25 years and which will function even more other 25 years without any problem. :palm:
 

Offline linux-works

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #4 on: September 15, 2015, 01:28:41 pm »
your fluke had the POPC feature, I see (physical offset phase compensation) !


lol

Offline quantalume

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #5 on: September 15, 2015, 02:46:08 pm »
I really like those older, trim, 70-series meters, before they bastardized the design with that ugly yellow surround case. In fact, I will not buy a test instrument that has a yellow case.  :rant:
 

Offline mos6502

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #6 on: September 15, 2015, 03:02:26 pm »
Just don't show the 250V glass fuse they used in this thing, or Dave will burst a blood vessel  :)

But hey, at least they give you a spare.  8)
for(;;);
 

Offline commongrounder

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #7 on: September 15, 2015, 07:55:16 pm »
It's a good thing the board is solder starved.  There would have been bridges on almost every pin on those chips if there had been more. :o
 

Offline DanielS

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #8 on: September 15, 2015, 08:38:51 pm »
It's a good thing the board is solder starved.  There would have been bridges on almost every pin on those chips if there had been more. :o
If there had been more solder, surface tension might have pulled the chip into alignment.
 

Offline lowimpedanceTopic starter

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #9 on: September 15, 2015, 11:38:30 pm »
Excuse me, but I find it necessary to have the particularly twisted mind to come and to do quality control on a meter which worked perfectly for over 25 years and which will function even more other 25 years without any problem. :palm:
Umm dude , re read to the end where I said "had it matterred, not one bit" , how ever do you seriously think this construction is acceptable ??  ::).
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline madalf71

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #10 on: September 16, 2015, 02:06:30 am »
Looks like mine was made on a Monday, little bit offset on one side.
 

Offline retiredcaps

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #11 on: September 16, 2015, 06:17:41 am »
With respect to U1, Excavatoree, our resident Fluke expert, mentioned

Has anyone mentioned that some of the early 70 series models suffered from a soldering defect of U1?  Seems some didn't have enough solder, or maybe the installation was bad or something, but the result is poor contact.  I'm not the worlds greatest smd solderer, but I've fixed a few that had that problem.

https://www.eevblog.com/forum/testgear/fluke-77-strange-demise/15/

Since the main IC is dated 1984, maybe this Friday one, is one that Excavatoree has seen?
 

Offline lowimpedanceTopic starter

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Re: A Fluke 77 made on a Friday afternoon !.
« Reply #12 on: September 16, 2015, 11:46:38 am »
With respect to U1, Excavatoree, our resident Fluke expert, mentioned

Has anyone mentioned that some of the early 70 series models suffered from a soldering defect of U1?  Seems some didn't have enough solder, or maybe the installation was bad or something, but the result is poor contact.  I'm not the worlds greatest smd solderer, but I've fixed a few that had that problem.

https://www.eevblog.com/forum/testgear/fluke-77-strange-demise/15/

Since the main IC is dated 1984, maybe this Friday one, is one that Excavatoree has seen?
Interesting, perhaps quite a few more 'Friday ones' exist !.
My meter has the alignment issue on both ICs and yet still functions no problems.
To note I did give the PCB a little bit of twist to see if the soldering or apparent lack off was an issue. It would seem to be okay and I think I will leave it be (if it ain't broke why fix it :D).
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 


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