Products > Test Equipment

Old Fluke Multimeters

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krivx:

--- Quote from: ModemHead on March 19, 2015, 11:00:59 pm ---
--- Quote from: kwochele on March 19, 2015, 10:09:44 pm ---3) The last digit does fluctuate on the 20V.   When I turn on the meter at the 20V selection connected to the D Cell (pretty confident the battery is 1.5620V based on my other meters) the 8060A/AA meter jumps to “-OL” then 1.574 after the display test and then immediately to 1.540, 1.548, 1.553 then it will count approximately 1 count per second 1.554, 1.555., etc until it reaches 1.560.  I noticed my second 8060 starts out the same way it just reaches the final value quicker.

4) The input jacks look good and I cleaned them with both WD-40 and then the Electronic cleaner.

Since it does eventually read the correct value after 5 – 10 seconds, could this be normal?

--- End quote ---

This has all the hallmarks of a contaminated PCB, assuming you have taken care of any leaking caps and made sure the power supplies are OK.  I do not like the sound of WD40 (or Radio Shack electronics cleaner, either) anywhere near the inside of this meter, it is very susceptible to developing leakage currents due to PCB contamination.  Dunk the whole thing in 91% or better IPA, scrub what you can get to with a brush, then allow to dry overnight.  A fan is a good thing.  I'd remove the MAC first, and make sure the socket is clean.  Scrub the MAC with IPA too.

--- End quote ---

When I repaired mine I had to replace electrolytics and the MAC socket. After cleaning the board I had a small residual reading with no leads, giving the MAC an IPA bath fixed it. Thanks for your article on a similar repair, it was very useful  :-+

kwochele:
lowimpedance / krivx,

I replaced the electrolytic capacitors but I did not see signs of leaking.   I checked U4 (pin3 to pin 5) and it was stable at -5.126 volts.

Interesting that you mention a dodgy socket as a possibility.  When I first received the meter the readings were off.  When I tried to calibrate VDC using R5 I could not get it to be repeatable.  I would set it then cycle power and the voltage reading would be all over the place again.   I took a shot and replaced the MAC from a donor 8060 and that seemed to correct the problem.  I set VDC using R5 to match my other Fluke and it has matched the second Fluke ever since.   What is interesting is that I have disassembled multiple Flukes and I always pull the chip, which up until this meter required a fair amount of effort.  The MAC on this meter can be easily pulled from the socket.

ModemHead / krivx,

A typically I do not admit to shopping at Radio Shack, however our local store was one of the ones closing and well I bought more than I should have.  I did not realize soaking the board in IPA was an option.  I will certainly do that as I noticed the Radio Shack electronic cleaner seems to leave a residue.   The WD40 is only for two areas; the on/off switch which is one of the reasons I pull the MAC and to remove corrosion on the inside of the  input jacks.  I try not to get any WD-40 on the main board.
 
For cleaning you are saying I can remove the MAC and soak the entire main board in IPA?

Thanks to everyone for their inputs.  Ken

ModemHead:

--- Quote from: kwochele on March 20, 2015, 01:41:12 am ---For cleaning you are saying I can remove the MAC and soak the entire main board in IPA?

--- End quote ---
I used to be squeamish about that but now I've done it so many times I don't worry about it anymore.  It doesn't seem to bother a thing, and often cures a number of ills.  The plastic cover on the muRata piezo will hold liquid, so blowing that out, along with the switches, with a duster can or compressed air is a good idea.  I always leave the board in front of a muffin fan for at least an hour or more for drying, overnight is better.

In case you haven't found it yet, you may want to read about my initial experience with an 8060A, especially the update at the very end.

The picture is a Fluke 8024B, but you get the idea.

retiredcaps:

--- Quote from: kwochele on March 19, 2015, 10:09:44 pm ---Since it does eventually read the correct value after 5 – 10 seconds, could this be normal?

--- End quote ---
Meters that take 5 to 10 seconds to settle on the correct range don't have a place in my household.   :--

I don't have my 8060A handy, but I recall it reads and settles on the correct value in probably 1 second.

The manual also say the same.

krivx:

--- Quote from: kwochele on March 20, 2015, 01:41:12 am ---lowimpedance / krivx,

I replaced the electrolytic capacitors but I did not see signs of leaking.   I checked U4 (pin3 to pin 5) and it was stable at -5.126 volts.

Interesting that you mention a dodgy socket as a possibility.  When I first received the meter the readings were off.  When I tried to calibrate VDC using R5 I could not get it to be repeatable.  I would set it then cycle power and the voltage reading would be all over the place again.   I took a shot and replaced the MAC from a donor 8060 and that seemed to correct the problem.  I set VDC using R5 to match my other Fluke and it has matched the second Fluke ever since.   What is interesting is that I have disassembled multiple Flukes and I always pull the chip, which up until this meter required a fair amount of effort.  The MAC on this meter can be easily pulled from the socket.

ModemHead / krivx,

A typically I do not admit to shopping at Radio Shack, however our local store was one of the ones closing and well I bought more than I should have.  I did not realize soaking the board in IPA was an option.  I will certainly do that as I noticed the Radio Shack electronic cleaner seems to leave a residue.   The WD40 is only for two areas; the on/off switch which is one of the reasons I pull the MAC and to remove corrosion on the inside of the  input jacks.  I try not to get any WD-40 on the main board.
 
For cleaning you are saying I can remove the MAC and soak the entire main board in IPA?

Thanks to everyone for their inputs.  Ken

--- End quote ---

My issue with the socket could be seen by eye, a few of the pins were corroded. This probably explained why I needed to clean the IC as well.

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