Fluke 8060a meter interconnect strip

I have an old IBM labelled Fluke built DMM (8060a equivalent) that hasn't worked in years for reasons I don't recall exactly, but seem to think it was stone dead. I had it apart and left in a box and, since my last 87 crapped out a few weeks ago, I needed the low ohms feature of one or the other so I took another look at the old IBM.

I found just about every electrolytic on the board physically leaky, and most down in value and ESR, some considerably. I replaced them all but when assembling the meter, I checked the two flexible rubber interconnect strips.. One of them is round and reads zero ohms all across it's length, so that one's good.

The other is a flat rectangular piece, and I cannot get any kind of resistance reading *anywhere* across it. I've cleaned it several times including using an abrasive last time and cannot get a whiff of conductance, and I've put considerable pressure on the test leads. I guess it being unassembled and sitting in free air must have poisoned it somehow as I don't recall it having any issues with erratic segments before the meter died.

It will be easy to hard wire this but was wondering if this is a low ohm transfer strip of something maybe a few ohms to a few thousand. If it's low ohms, I'll just hard wire it. If it's something other, there's plenty of room to put in 1/8 w resistors of appropriate value.

Anyone know the approximate resistance of the strip?

 

[pfjw@aol.com]

On Sunday, May 1, 2016 at 3:41:23 PM UTC-4, ohg...@gmail.com wrote:

> Anyone know the approximate resistance of the strip?

It would not be in the best interest of any (legitimate) manufacturer to build a precision-resistance into an interconnect strip. As you have discovered, they can be volatile, and any actual planned resistance will necessarily generate heat - leading to even quicker failure.

Hardwire it - and if it works properly (and it should if this is the only problem), you are done.

Peter Wieck
Melrose Park, PA

 

On Sunday, May 1, 2016 at 4:17:44 PM UTC-4, pf...@aol.com wrote:

On Sunday, May 1, 2016 at 3:41:23 PM UTC-4, ohg...@gmail.com wrote:

Anyone know the approximate resistance of the strip?

It would not be in the best interest of any (legitimate) manufacturer to build a precision-resistance into an interconnect strip. As you have discovered, they can be volatile, and any actual planned resistance will necessarily generate heat - leading to even quicker failure.

Hardwire it - and if it works properly (and it should if this is the only problem), you are done.

Peter Wieck
Melrose Park, PA

Thanks Peter. I don't think any resistance (assuming there is any) would be a problem. The strip in question feeds the LCD display glass and the draw would likely be few micro amps at 5V. I was thinking in terms of the conductive pads used to active scan lines in cheap keyboards. Those measure from a few dozen ohms to a few K ohms and work properly.

In any case, I'll take your advice and hard wire it when I get to work tomorrow and see what happens.

John

 

[Wolfgang Allinger]

On 01 May 16 at group /sci/electronics/repair in article 1ec60e64-b347-4d72-8754-44536d9bd8ad@googlegroups.com
<ohger1s@gmail.com> wrote:

I have an old IBM labelled Fluke built DMM (8060a equivalent) that
hasn't worked in years for reasons I don't recall exactly, but seem to
think it was stone dead. I had it apart and left in a box and, since
my last 87 crapped out a few weeks ago, I needed the low ohms feature
of one or the other so I took another look at the old IBM.

I found just about every electrolytic on the board physically leaky,
and most down in value and ESR, some considerably. I replaced them
all but when assembling the meter, I checked the two flexible rubber
interconnect strips. One of them is round and reads zero ohms all
across it's length, so that one's good.

The other is a flat rectangular piece, and I cannot get any kind of
resistance reading *anywhere* across it. I've cleaned it several
times including using an abrasive last time and cannot get a whiff of
conductance, and I've put considerable pressure on the test leads. I
guess it being unassembled and sitting in free air must have poisoned
it somehow as I don't recall it having any issues with erratic
segments before the meter died.

It will be easy to hard wire this but was wondering if this is a low
ohm transfer strip of something maybe a few ohms to a few thousand.
If it's low ohms, I'll just hard wire it. If it's something other,
there's plenty of room to put in 1/8 w resistors of appropriate value.

Anyone know the approximate resistance of the strip?

see
http://mrmodemhead.com/blog/fluke-8060a-repair/

with the answer from Jack on August 18,2014 near the end



Saludos (an alle Vernünftigen, Rest sh. sig)
Wolfgang

--
Wolfgang Allinger, anerkannter Trollallergiker reply Adresse gesetzt!
Ich diskutiere zukünftig weniger mit Idioten, denn sie ziehen mich auf
ihr Niveau herunter und schlagen mich dort mit ihrer Erfahrung!
(lt. alter usenet Weisheit) iPod, iPhone, iPad, iTunes, iRak, iDiot

 

[Jeff Liebermann]

On Sun, 1 May 2016 12:41:20 -0700 (PDT), ohger1s@gmail.com wrote:

>Anyone know the approximate resistance of the strip?

Some photos of the insides of an 8024a, which is fairly close in
construction to an 8060a.
<http://www.eevblog.com/forum/testgear/fluke-8024b-33-years-old-and-still-going-strong!-beware-3mb-photos/>
The ribbon cable:
<http://s193.photobucket.com/user/Bl4ckW0lfi3/media/Fluke8024B-09_zps4b433951.jpg.html>
The ribbon cable between the two boards is made from screened
graphite, which tends to crack if flexed. I found a similar ribbon
cable, but made from flattened copper wire that looked more reliable.
I removed the original ribbon cable, clamped in the new cable, and
after a bit of jiggling, got it to make a connection without
soldering. Once it was working, I used hot melt glue to hold it in
place. I suppose soldering would have been easier, but at the time, I
didn't want to wreck the meter.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Sunday, May 1, 2016 at 5:53:42 PM UTC-4, Jeff Liebermann wrote:

On Sun, 1 May 2016 12:41:20 -0700 (PDT), ohger1s@gmail.com wrote:

Anyone know the approximate resistance of the strip?

Some photos of the insides of an 8024a, which is fairly close in
construction to an 8060a.
http://www.eevblog.com/forum/testgear/fluke-8024b-33-years-old-and-still-going-strong!-beware-3mb-photos/
The ribbon cable:
http://s193.photobucket.com/user/Bl4ckW0lfi3/media/Fluke8024B-09_zps4b433951.jpg.html
The ribbon cable between the two boards is made from screened
graphite, which tends to crack if flexed. I found a similar ribbon
cable, but made from flattened copper wire that looked more reliable.
I removed the original ribbon cable, clamped in the new cable, and
after a bit of jiggling, got it to make a connection without
soldering. Once it was working, I used hot melt glue to hold it in
place. I suppose soldering would have been easier, but at the time, I
didn't want to wreck the meter.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Other than the shape of the boards, they're not much alike. The 8060 has no flexible membrane circuit.

For the heck of it, I took a straight edge and a sharp razor and removed about a 16th from both sides of the rubber conductive strip, and still no continuity whatsoever, so I hard wired the display.

It now starts, boots, and passes the power up test. The display is clear and has full contrast.

The problem is that it's reading voltages and resistances that don't exist, even though it does read my test voltages and resistances. I guess I have to take this apart again and do a better job of cleaning the electrolyte off the board.

The link posted by an earlier poster shows problems with leakage below the main chip/socket only. If I knew that would be the only problem to address, I'd pull the socket and try it. The problem is is that every individual solution requires undoing the display hardwire, so I'm trying to formulate a plan to effectively clean this in one shot.

John
John

 

On Sunday, May 1, 2016 at 5:53:42 PM UTC-4, Jeff Liebermann wrote:

On Sun, 1 May 2016 12:41:20 -0700 (PDT), ohger1s@gmail.com wrote:

Anyone know the approximate resistance of the strip?

Some photos of the insides of an 8024a, which is fairly close in
construction to an 8060a.
http://www.eevblog.com/forum/testgear/fluke-8024b-33-years-old-and-still-going-strong!-beware-3mb-photos/
The ribbon cable:
http://s193.photobucket.com/user/Bl4ckW0lfi3/media/Fluke8024B-09_zps4b433951.jpg.html
The ribbon cable between the two boards is made from screened
graphite, which tends to crack if flexed. I found a similar ribbon
cable, but made from flattened copper wire that looked more reliable.
I removed the original ribbon cable, clamped in the new cable, and
after a bit of jiggling, got it to make a connection without
soldering. Once it was working, I used hot melt glue to hold it in
place. I suppose soldering would have been easier, but at the time, I
didn't want to wreck the meter.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Other than the shape of the boards, the 8026 and 8060 are not much alike. The 8060 has no flexible membrane circuit.

For the heck of it, I took a straight edge and a sharp razor and removed about a 16th from both sides of the rubber conductive strip, and still no continuity whatsoever, so I hard wired the display.

It now starts, boots, and passes the power up test. The display is clear and has full contrast.

The problem is that it's reading voltages and resistances that don't exist, even though it does read my test voltages and resistances. I guess I have to take this apart again and do a better job of cleaning the electrolyte off the board.

The link posted by an earlier poster shows problems with leakage below the main chip/socket only. If I knew that would be the only problem to address, I'd pull the socket and try it. The problem is is that every individual solution requires undoing the display hardwire, so I'm trying to formulate a plan to effectively clean this in one shot.

John

 

On Monday, May 2, 2016 at 11:39:00 AM UTC-4, ohg...@gmail.com wrote:

The link posted by an earlier poster shows problems with leakage below the main chip/socket only. If I knew that would be the only problem to address, I'd pull the socket and try it. The problem is is that every individual solution requires undoing the display hardwire, so I'm trying to formulate a plan to effectively clean this in one shot.

John

I pulled the main IC/socket and there's no sign of leakage on or under the socket pins or board. The capacitor leakage seems to be contained under the switch assy.

I removed three variable caps which hugged the board and removed the power switch. Every other part is either high enough off the board not to be touched by a very shallow bath or would not be unaffected by one. Next plan is to give it a hot shallow bath of distilled water followed by a wash of IPA and a few hours in the hot box. I have other things on my bench right now so I won't play any more with this for a few days at least.

John

 

On Monday, May 2, 2016 at 2:14:13 PM UTC-4, Jeff Liebermann wrote:

Never mind. I found the type in the user manual on Pg 6-5 in:
http://assets.fluke.com/manuals/8060a_3vimeng0200.pdf
SCREW,PH,P,THD FORM,STL,7-19,.750

You lost the screws, somewhere along the way I lost one of the push buttons. Too bad I can't get one of those in a hardware store!

John

 

[Jeff Liebermann]

On Mon, 2 May 2016 08:37:14 -0700 (PDT), ohger1s@gmail.com wrote:

Other than the shape of the boards, they're not much alike.
The 8060 has no flexible membrane circuit.

Oops. I couldn't find any decent 8060a photos other than the repair
article, so I guessed that they were the same from memory. Sorry for
the misinformation.
<http://mrmodemhead.com/blog/fluke-8060a-repair/>

The problem is that it's reading voltages and resistances that don't
exist, even though it does read my test voltages and resistances.
I guess I have to take this apart again and do a better job of
cleaning the electrolyte off the board.

The link posted by an earlier poster shows problems with leakage
below the main chip/socket only. If I knew that would be the only
problem to address, I'd pull the socket and try it. The problem
is is that every individual solution requires undoing the display
hardwire, so I'm trying to formulate a plan to effectively
clean this in one shot.

Well, I may join you on this repair. I just found my long lost Fluke
8060a. About +1.5mv of residual reading on the 200mv scale. I'll
drag it to my office, take some photos, and measure the Zebra strip
resistance for you (probably tomorrow). Meanwhile, this might offer a
clue as to the resistance;
<https://en.wikipedia.org/wiki/Elastomeric_connector>
<http://www.fujipoly.com/usa/design-guidelines/89.html>


Unrelated dumb question. The three case screws for this Fluke 8060A
seem to have walked away. What's the thread designation so I can buy
some replacements? There's plenty similar screws on eBay:
<http://www.ebay.com/sch/i.html?_nkw=fluke+screws>
but none specifically for the 8000 series DMM. $1.50/ea including
shipping. I'll probably do better at the hardware store
Never mind. I found the type in the user manual on Pg 6-5 in:
<http://assets.fluke.com/manuals/8060a_3vimeng0200.pdf>
SCREW,PH,P,THD FORM,STL,7-19,.750




--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Mon, 2 May 2016 13:57:02 -0700 (PDT), ohger1s@gmail.com wrote:

On Monday, May 2, 2016 at 2:14:13 PM UTC-4, Jeff Liebermann wrote:

Never mind. I found the type in the user manual on Pg 6-5 in:
http://assets.fluke.com/manuals/8060a_3vimeng0200.pdf
SCREW,PH,P,THD FORM,STL,7-19,.750

You lost the screws,

I several large candy jars that are full of random hardware. I
probably tossed the screws in one of them. It's easier to buy
replacements than to excavate them from the jars. Needle in haystack.
The local Ace hardware store didn't have any plastic screws.

somewhere along the way I lost one
of the push buttons. Too bad I can't get one of those in a
hardware store!

You can get another carcass on eBay. Or buy one from the test
equipment cannibals:
<http://www.ebay.com/sch/i.html?_nkw=fluke+dvm+switch+cover>
Notice that the LCD display is starting to turn black along the bottom
edge. Most of my various Fluke meters have the same problem.

I tore my 8050a apart and tooks some photos and measurements:
<http://802.11junk.com/jeffl/pics/Fluke%208060a/>

This Zebra strip measures about 1K ohms:
<http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-1.jpg>

while this one measures about 5 ohms:
<http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-2.jpg>

Measuring the resistance was a PITA. The problem was determining
whether I was measuring the resistance of one contact, or a bunch of
them in parallel. I didn't want to drag out the microscope, so I
resorted to a trick. I placed the flat side of one DVM probe across a
section of the strip so that it would connect to a large number of
conductive strips. I then used a very sharp needle tip to make
contact on the other side. It wasn't perfect, but I think it was good
enough.

More photos when I have time. Anything else you want photographed or
measured?


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Mon, 02 May 2016 11:14:14 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

Well, I may join you on this repair. I just found my long lost Fluke
8060a. About +1.5mv of residual reading on the 200mv scale. I'll
drag it to my office, take some photos, and measure the Zebra strip
resistance for you (probably tomorrow).

Curses, foiled again. While tearing apart the meter, taking photos,
and putting it back together, I managed to transfer enough blood,
sweat, and tears onto the PCB and components to wreck the calibration
and add some more leakage. Instead of +1.5mv of residual junk on the
200mv scale, I now have about -7mv of leakage. The next time I work on
this meter, I'll remember to use latex or nitrile gloves. 90% alcohol
and bake dry scheduled for next weekend.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Monday, May 2, 2016 at 9:06:34 PM UTC-4, Jeff Liebermann wrote:

This Zebra strip measures about 1K ohms:
http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-1.jpg

while this one measures about 5 ohms:
http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-2.jpg

Measuring the resistance was a PITA. The problem was determining
whether I was measuring the resistance of one contact, or a bunch of
them in parallel.

The conductors are *very* dense in this particular zebra strip and I'd guess that there's at a minimum 10 conductors presented across the large pads on the boards they make contact with, so I'd venture that if they're 5 ohms each and 10 or more are paralleled across the pads, a wire jumper is just fine.

More photos when I have time. Anything else you want photographed or
measured?

Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

No, I think I'm OK at this point. After it takes it's IPA bath I'll reassemble and see where I'm at. Thanks for the information!

If the meter turns out OK, I'll probably pick up a DOA meter on ebay for parts, including the missing button. If the meter still is a bit wonky, I'll remove the switch pack and give it an ultrasonic bath.

The bottom of my display looks exactly like yours. Are you sure this is abnormal? The bottom edge is where the round zebra strip contacts the LCD electrically on the back side, so maybe that thicker area is normal. The border around the entire LCD display is black although much thinner.

John

 

[Jeff Liebermann]

On Tue, 3 May 2016 04:46:25 -0700 (PDT), ohger1s@gmail.com wrote:

On Monday, May 2, 2016 at 9:06:34 PM UTC-4, Jeff Liebermann wrote:

This Zebra strip measures about 1K ohms:
http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-1.jpg

while this one measures about 5 ohms:
http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-2.jpg

Measuring the resistance was a PITA. The problem was determining
whether I was measuring the resistance of one contact, or a bunch of
them in parallel.

The conductors are *very* dense in this particular zebra strip and
I'd guess that there's at a minimum 10 conductors presented across
the large pads on the boards they make contact with, so I'd venture
that if they're 5 ohms each and 10 or more are paralleled across
the pads, a wire jumper is just fine.

Yep. I can measure the resistance from PCB pad to pad in that area
if you want. However, it will need to wait a few days. Bizzeee.

I had quite a struggle reassembling the LCD display. The LCD glass
fits into a slot of sorts in the plastic frame that requires the Zebra
strip to be compressed. Insert just the glass LCD plate first and use
brute force to compress the Zebra strip. Then, slide in the plastic
screen protector and frame. If anyone has a better way, I would be
interested.

After it takes it's IPA bath I'll reassemble and see where I'm at.
Thanks for the information!

The article at:
<http://mrmodemhead.com/blog/fluke-8060a-repair/>
(near the bottom) says to let it dry for a few hours after an alcohol
bath. I've had the same experience. Alcohol absorbs moisture from
the air and will dump this moisture onto the PCB during cleaning. It
takes a while to evaporate.

If the meter turns out OK, I'll probably pick up a DOA meter on ebay
for parts, including the missing button. If the meter still is a bit
wonky, I'll remove the switch pack and give it an ultrasonic bath.

I've destroyed a few two-way radios using a 10 watt ultrasonic
cleaner. It tends to kill semiconductor devices with unsupported wire
bonds to the chip. I suggest using a brush instead. A brush doesn't
get under IC sockets and overhanging components, so I like flood the
area with alcohol, let it sit for about 30 seconds, and blow it out
with compressed air. Not the best way, but better than shaking the
meter to death. I haven't done too many DVM's so I don't know what a
solvent bath will do the rotary switch.

The bottom of my display looks exactly like yours. Are you sure
this is abnormal? The bottom edge is where the round zebra strip
contacts the LCD electrically on the back side, so maybe that thicker
area is normal. The border around the entire LCD display is black
although much thinner.

No, I'm not sure. My eyesight isn't that great any more. I've seen a
much more extreme black edge smear on other Fluke LCD displays. Here's
an 8020A display disassembled:
<http://s1259.photobucket.com/user/mrmodemhead/media/Fluke%208020B/F8020B_018.jpg.html>
It has a black border, but it's very different from the 8060a:
<http://802.11junk.com/jeffl/pics/Fluke%208060a/Fluke-8060a-LCD-1.jpg>

You might be right as the black line seems rather consistent instead
of the creeping black blob caused by case leakage. I'll put it under
the microscope later and double check. This is what it *MIGHT* look
like eventually:
<http://www.vintage-radio.net/forum/attachment.php?attachmentid=31080&d=1260895739>
<http://www.eevblog.com/forum/chat/recovery-of-an-old-fluke-8020a-with-a-bad-lcd/?action=dlattach;attach=5445>
<http://www.eevblog.com/forum/chat/just-got-my-'new'-multimeter-the-family-become-larger/?action=dlattach;attach=1305;image>

Still looking for the missing case screws. No luck so far.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Sunday, May 1, 2016 at 3:41:23 PM UTC-4, ohg...@gmail.com wrote:

I have an old IBM labelled Fluke built DMM (8060a equivalent) that hasn't worked in years for reasons I don't recall exactly, but seem to think it was stone dead. I had it apart and left in a box and, since my last 87 crapped out a few weeks ago, I needed the low ohms feature of one or the other so I took another look at the old IBM.

I found just about every electrolytic on the board physically leaky, and most down in value and ESR, some considerably. I replaced them all but when assembling the meter, I checked the two flexible rubber interconnect strips. One of them is round and reads zero ohms all across it's length, so that one's good.

The other is a flat rectangular piece, and I cannot get any kind of resistance reading *anywhere* across it. I've cleaned it several times including using an abrasive last time and cannot get a whiff of conductance, and I've put considerable pressure on the test leads. I guess it being unassembled and sitting in free air must have poisoned it somehow as I don't recall it having any issues with erratic segments before the meter died.

It will be easy to hard wire this but was wondering if this is a low ohm transfer strip of something maybe a few ohms to a few thousand. If it's low ohms, I'll just hard wire it. If it's something other, there's plenty of room to put in 1/8 w resistors of appropriate value.

Anyone know the approximate resistance of the strip?

I removed the switch assy, the main IC socket, and the variable capacitors from the board. Several rounds of 91% IPA bathing has not cleaned the sticky electrolyte off the board, except where I could get an acid brush in to scrub. Two remaining options are to remove every other part off the board and scrub with a fiber brush or go to a more aggressive cleaner. I'm going with option two and see what happens.

John

 

On Wednesday, May 4, 2016 at 2:59:17 PM UTC-4, Jeff Liebermann wrote:

On Wed, 4 May 2016 10:23:09 -0700 (PDT), ohger1s@gmail.com wrote:

I removed the switch assy, the main IC socket, and the variable capacitors from the board. Several rounds of 91% IPA bathing has not cleaned the sticky electrolyte off the board, except where I could get an acid brush in to scrub. Two remaining options are to remove every other part off the board and scrub with a fiber brush or go to a more aggressive cleaner. I'm going with option two and see what happens.
John

Older electrolytic capacitors used ethylene glycol and boric acid for
electrolyte. Later versions used dimethylformamide,
dimethylacetamide, or butyrolactone. If you look these up on
Wikipedia, the table on the right includes solubility:
https://en.wikipedia.org/wiki/Ethylene_glycol
https://en.wikipedia.org/wiki/Dimethylacetamide
https://en.wikipedia.org/wiki/Dimethylformamide
https://en.wikipedia.org/wiki/Gamma-Butyrolactone
I would try detergent and water first, followed by a distilled or
deoinized water rinse. If that fails, start up the ladder of
chlorinated hydrocarbon solvents, starting with alcohol. I wouldn't
go much past trichlorethane or trichlorethylene which will probably
peel off the PCB printing, labels, and maybe the silk screening. Some
of these will also attack the epoxy that holds the PCB together. Be
careful and good luck.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

That makes a lot of sense. As I was unsoldering all the leaky caps, I never once got a whiff of low tide. When I was rebuilding Sony and Canon camcorders in the 90s most of them needed 40 or 50 smd caps, and my bench smelled like catch of the day. Clearly the formulation is different for the caps in the Flukes from what we see nowadays.

Anyway, your advice to avoid ultrasonic cleaners made way too much sense so I went ahead and soaked the board with my favorite circuit board cleaner; Fantastik. After a few soaks and rinses, the board looks, well, fantastic. It's clean as a whistle and all the goo is gone, including the crap under the inline packages and ICs. I rinsed in distilled water and now it's getting it's last IPA bath. I'll let it dry and reassemble in a few days and hope for the best.

And if that's your ground mail, I can send you two screws I have off a non-working 85 that I think needs a main chip. This meter crapped about 8 years ago and I misplaced one of the screws, but if you want the other two, they're yours. I'm on the east coast so it'll be a week.

John

 

[Jeff Liebermann]

On Wed, 4 May 2016 10:23:09 -0700 (PDT), ohger1s@gmail.com wrote:

I removed the switch assy, the main IC socket, and the variable capacitors from the board. Several rounds of 91% IPA bathing has not cleaned the sticky electrolyte off the board, except where I could get an acid brush in to scrub. Two remaining options are to remove every other part off the board and scrub with a fiber brush or go to a more aggressive cleaner. I'm going with option two and see what happens.
John

Older electrolytic capacitors used ethylene glycol and boric acid for
electrolyte. Later versions used dimethylformamide,
dimethylacetamide, or butyrolactone. If you look these up on
Wikipedia, the table on the right includes solubility:
<https://en.wikipedia.org/wiki/Ethylene_glycol>
<https://en.wikipedia.org/wiki/Dimethylacetamide>
<https://en.wikipedia.org/wiki/Dimethylformamide>
<https://en.wikipedia.org/wiki/Gamma-Butyrolactone>
I would try detergent and water first, followed by a distilled or
deoinized water rinse. If that fails, start up the ladder of
chlorinated hydrocarbon solvents, starting with alcohol. I wouldn't
go much past trichlorethane or trichlorethylene which will probably
peel off the PCB printing, labels, and maybe the silk screening. Some
of these will also attack the epoxy that holds the PCB together. Be
careful and good luck.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Ralph Mowery]

In article <rtgkibdr3po7m4lknc64kkn04ndlvdk0hu@4ax.com>,
jeffl@cruzio.com says...

I would try detergent and water first, followed by a distilled or
deoinized water rinse. If that fails, start up the ladder of
chlorinated hydrocarbon solvents, starting with alcohol. I wouldn't
go much past trichlorethane or trichlorethylene which will probably
peel off the PCB printing, labels, and maybe the silk screening. Some
of these will also attack the epoxy that holds the PCB together. Be
careful and good luck.

I have seen references to mixing IPA and acetone 50/50 to do some PC
board cleaning. Any thing good or bad about doing that ?

 

[Jeff Liebermann]

On Wed, 4 May 2016 15:07:53 -0700 (PDT), ohger1s@gmail.com wrote:

That makes a lot of sense. As I was unsoldering all the leaky caps,
I never once got a whiff of low tide. When I was rebuilding Sony
and Canon camcorders in the 90s most of them needed 40 or 50
smd caps, and my bench smelled like catch of the day. Clearly
the formulation is different for the caps in the Flukes from
what we see nowadays.

Yep. Lots of changes in electrolyte. I really don't know what Fluke
was using.

Anyway, your advice to avoid ultrasonic cleaners made way too
much sense so I went ahead and soaked the board with my favorite
circuit board cleaner; Fantastik.

Ugh. I use Formula 409. I had some issues with Fantastik leaving
some residue that didn't evaporate. Fortunately, most seemed to wash
off with deionized water, so it wasn't fatal. Residue was easy enough
to detect by leaving a blob of Fantastik on a microscope slide, let it
evaporate, and inspect the bathtub ring. There wasn't much, but there
was enough to make me worry.

Fantastik has changed their formulation over the years. This should
be the latest (Formula 35*19431):
<http://www.whatsinsidescjohnson.com/us/en/brands/fantastik/fantastik-mini-concentrated-kitchen-cleaner>
I have a small problem with the oily fragrance, which does evaporate,
but very slowly. The stabilizer and dye also might leave a residue,
but I'm not sure. Both 409 and Fantastik are highly alkaline (pH=10.5
to 11.5), which should not be a problem. The grease was cleaned by
the inclusion of ethyl alcohol.

After a few soaks and rinses, the board looks, well, fantastic.
It's clean as a whistle and all the goo is gone, including the crap
under the inline packages and ICs. I rinsed in distilled water and
now it's getting it's last IPA bath. I'll let it dry and reassemble
in a few days and hope for the best.

Sounds good. Check the residual voltage displayed on the 200mv scale
to see if the PCB is still leaking. I know mine is leaking from all
my unprotected handling.

And if that's your ground mail, I can send you two screws I have
off a non-working 85 that I think needs a main chip. This meter
crapped about 8 years ago and I misplaced one of the screws, but if
you want the other two, they're yours. I'm on the east coast so
it'll be a week.

Thanks. The address is my palatial office. I could use the screws to
finish my 8060A. However, if you think you're going to eventually fix
the Model 85, I suggest you keep them. I'll eventually find where I
misplaced my screws or find replacements.

Also, I'm still not sure about the black line at the bottom of the
LCD. However, I'm inclined to believer that you're correct and that
mine is normal. When reassembled, the screen does not show the black
line and everything else looks normal.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Wed, 4 May 2016 17:59:53 -0400, Ralph Mowery
<rmowery28146@earthlink.net> wrote:

I have seen references to mixing IPA and acetone 50/50 to do some PC
board cleaning. Any thing good or bad about doing that ?

No. Bad idea. Don't do that.

Acetone will attack many plastics (ABS, polycarbonate, polystyrene,
polyethylene, vinyl, etc). Before you use ANY manner of solvent, do
some research on a "chemical compatibility chart" for the materials
you expect to be using.
<https://capolight.files.wordpress.com/2010/08/solvent_compatibility.jpg>
Be sure to check compatibility with epoxy, as that's what the PCB is
made from.

For example:
<http://www.coleparmer.com/Chemical-Resistance>
shows that:
ABS plastic and acetone = "Severe Effect"
ABS plastic and 50% acetone and water = "Severe Effect"

Also, I guess I should mention that there are many different types of
alcohols (amyl, benzyl, butyl, diacetone, ethyl, hexyl, ibsbutyl,
methyl, octyl, propyl, etc). Characteristics vary so don't assume
that some random alcohol is safe just because isopropyl alcohol didn't
destroy some plastic. I had to learn that lesson when I switched to
the "alcohol" sold by the local hardware store, and found it far more
aggressive than the 91% drug store variety.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558