Another Fluke87 problem

[planenut2000]

I cleaned the circuit board twice with Mac's Electronic cleaner from napa auto parts, with a little light tooth brush action. And when my wife wasn't looking i put in her oven at 175 for about 45mins. i would have heated for longer but she caught me!!!  But that fixed it. All readings are normal now!
Thanks to all you guys for the help!!!

[james_s]

Glad to hear this worked out. It should give you many years of service now that it works.

[planenut2000]

Well almost fixed. I'm getting beeping like the leads are in the wrong position, but leads aren't plugged in. This happens when the meter is first turned or when its in a cooler building and usually clears by itself.
Anything come to mind that could be temp related?
Are the stray mv readings on the ac and dc ok?
Otherwise when i use it to measure something it always seems to be working.

[bdunham7]

The input jacks are all split and the two halves are connected by the lead when you plug it in.  The COM and VOLT/OHM jack are tied together but the two current jacks remain split between a lead sensing circuit and the current circuit.  Any contamination that allows leakage from one side of the jack to the other will cause this problem.  It could be caused by more contamination on the board right near the current jacks or it could be problem inside the input jack assembly itself.  For the jacks, I would try pouring in some IPA or your board cleaner, swishing it around, emptying it out and then blowing out with compressed air.

[james_s]

Maybe try cleaning the jack out with a Q-tip dipped in alcohol? Looks about the right size.

[planenut2000]

I made some head way again. I re-soldered the input jack block again, re-soldered RT1 and R1, actually bridged them together, they were only a mm apart anyways. re-soldered R7, also W1 and W2. Re-soldered the 9volt battery wires. Cleaned the PCB with electronic cleaner and put it in the oven for 20min at 180. So far the meter shows only 2.8mv on the ac scale, 0 volts on the dcv scale, .2mv on the dcmv scale, OL on the ohm scale.
Hopefully i don't get the lead beeping alarm tomorrow when i retry it.

[planenut2000]

i think i am going to say the meter is fixed. i had it in the refrigerator overnight and all readings were normal with no stray voltages on the dcv or dcmv ranges and less then 1.5 mv on the ac scale. Ohm scale showed OL
Thanks to everyone who guided this repair!

[james_s]

Certainly sounds like it's working properly. Glad it all worked out.

[planenut2000]

Well I just give up!!!!
I had this meter working great, none of the problems that were talked about earlier. I put it away on the shelf and when i went to use it a couple of days ago its beeping on every setting! i blew compressed air in the input jacks and made no difference.

[planenut2000]

Very interesting update to this repair!
The fluke 87 is working perfectly now!! I did nothing to it except remove it for a few days from a protective foam lined hard case i purchased for it.
Is it possible that a sealed case could be holding high moisture or fumes from its mfg process that could be causing the fluke to show stray voltages and beep like the leads are in wrong?
Could this be because the prior PCB repairs need to be resealed?

If i leave it out of the case everything is normal, If i put it back in the case, the fluke messed up within a few days!

[m3vuv]

I once had an issue with my fluke 83v saying probes were in wrong and beeping,drove me nuts,i first tried cleaning the jacks with cotton buds but didnt help,in the end i unsoldered the jack assy,put it inside a sock and threw it in the washing machine when i did a wash,gave it 2 days in the airing cupboard to dry then refitted it,its  been perfect ever since,that must of been 4yrs ago.

[m3vuv]

why tf,do ppl say use ipa to clean corrosion,since when has alcohol dissolved corrosion?,i think you would do better pissing on it imho.

[Swake]

My 30-years old Fluke 85 has the same 'beeping' behavior when it is located in a high humidity environment for too long. Typically this would happen when it is stored overnight in an unheated shed, especially during the winter period. I believe it is due to condensation.

I never store it in the shed anymore in the winter months and have not had the beeping error since. Didn't change or clean anything.

[planenut2000]

My fluke is doing good for now. Its in a cold aircraft hanger and working. It does mess up if it rains for a few days. Right now the humdity is low due to lower temps and snow in the forecast.
There should be something to seal the pcb that i repaired previously