Fluke 189 multimeter repair advice needed

[BILLPOD]

My 189 still has the protective film on the screen that came on it when I bought it new in 2007.  I don't think it is an 'official' screen protector, but it has worked well.  I buy cheap cell phone screen protectors and cut them down for use on all my other meters.  Good job getting your 189 working again.

[sw2022]

Thanks, it made me very happy 😀. I’d used that meter for years even if I temporarily forgot how expensive it was to buy. Part of you thinks all through the process that it’s going to be scrap, people here inspired me to keep the faith!

Steve

[daisizhou]

fluke 189 Note that there are lithium batteries inside, which are easy to leak.
While 189 can store data, I prefer fluke 187

[sw2022]

Wonder if it’s possible to replace the lithium battery with new

[Shock]

It's not a battery, it's a super cap. A known issue and source of contamination due to physically leaking. It's well documented on the forums here in several threads.

[alm]

What I've done in the past, though this was on flat display lenses, was to sand them with wet-and-dry sandpaper from coarse enough to remove the scratch down to the finest grit I could buy, and then polish until its smooth again.

[sw2022]

Sounds possible I might try that, a bit scary in that it will dull the plastic and will definitely need the right polish to finish I guess

[alm]

Yes, you basically go to fully opaque but no big scratches down to polished and transparent again. Search this forum, I'm pretty sure people have written about this and recommended specific plastic polishes. Quite possibly by robrenz.

[sw2022]

Will do thanks!

[rsjsouza]

Great job in restoring one more fine piece of equipment!

I would be very careful with the polishing process: it is easy to make mistakes which, if anything goes wrong, will feel much worse now the meter is working. I would practice and practice on anything else before even trying something on the 189. The user Robrenz mentioned by alm is an incredible machinist with gobs of practice on his hands.

[sw2022]

Comments noted. Still thinking on whether to do anything more at all. I used the meter in anger yesterday and was very happy with it!

Steve

[alm]

I agree that you should consider if you want to fix this. For what it's worth, I certainly don't have the experience Robrenz has, and I did this without any problems. But I can see a potential problem polishing close to the edge of the frame.

User modemhead used to repair a lot of multimeters. You could search this forum and his website if he came up with a simpler solution.

[sw2022]

Thanks. His pics of a 189 overhaul were really helpful. Especially when a couple of switch contacts dropped loose, I sorted the orientation from there,

Steve

[Trader]

So ... I’ve measured the resistance across the split socket, best way seemed to be to press the meter probes on the cleaned tips of the jack sockets pins. See my pics. I get 1.31M accross the 10A socket and 1.38M for the 400mA socket. That’s of course with the board out of the meter case as pictured. Seems lower than what was suggested though almost identical for the two, obviously there’s an input circuit in the loop here though. Certainly nowhere near a short...

Steve

Hi sw2022, congrats you solve that problem.  I have the same issue, when you measured 1.31M (on A) and 1.38M (on mA), I measured 1.35M and 1.25M (oscillating between 1.2M and 1.3M).

It's possible for you to check again the same places?

I removed the jack, and even without the input jacks and cleaning the PCB, the LEADS beep doesn't stop.

If I blow warm air, the LEADS warning stops, but returns after a while.  Weird.

[sw2022]

Hi,

The meter still works well, the resistance readings across the two socket shells are 400mA socket 2.97M, 10A socket 2.43M. These are higher than yours. I pre cleaned the sockets physically using a sharp probe then pipe cleaner socked in alcohol. I then soaked my board for days in 100 pc isopropyl alcohol, with also lots of spray rinses with clean alcohol after the soak. I sprayed out the sockets also using a syringe. I then dried it both with hot air then leaving it in a cupboard for days. It’s interesting that function returns to your board when you warm it, are you sure there is no damp? Was the isopropyl alcohol 100 pc, I guess any water is not good,

Steve

[Trader]

My F189 was stored in a humid environment for several years.

I kept hot air (150F) on it for 10 hours, I guess the DMM is super dry and cleaned, I also removed the input jacks. Is weird that up to now the only solution for this problem is "cleaning", I wonder if some components (diode, resistance, etc) could be defective.

After warming, it works and the measures are correct, when the temperature returns to normal, starts beeping.

So, you soaked the Entire Board in 100% alcohol?

Thanks.

[sw2022]

I soaked approximately the bottom half of the board. I left the sockets in place and stood the thing in a plastic container, leaving the display end out.

Steve

[ewtotem]

It is somewhat common for the 189 and 187 to have the 4 post assembly break. The only solution is to replace it (Fluke 4611374)