Fluke 87 IV - repair log

[frenky]

I have locally bought (for 50€) Fluke 87 IV that wouldn't power on.

It looks like it was used a A LOT. 




On first inspection i noticed heavily corroded battery terminals (and one broken) which I took out for cleaning.


Dumped in vinegar for an hour:



I will solder a thin layer over contacts to prevent future corrosion. And also need to fix one broken tab.



For the first test of DMM I quickly soldered wires directly to PCB and It seems to work just fine...



Full resolution:

While trying to pry out dial knob, the screen plexiglass cracked, so there is more work to do... 

[Phil Smith]

Hey frenky,

Hah, looks like this meter has seen better days...or a lot of torture tests))
Anyway, as far as I can see, the PCB is in a nice condition

Keep up good work, looking forward to your log)

Regards,
Phil.

[Bushougoma]

This is the reason why I try to avoid meters that take AA or AAA batteries and prefer 9 volt cell models. 9 volt cells are actually multiple AAAA cells inside a metal case which contains the crud when they leak I've yet to see an old 9 volt cell leak. Bulge sure but not leak.

I'd highly recommend only using AA primary lithium cells like Energizer Ultimate Lithium if you intend to store the meter long term with batteries inside.

I made the same mistake with my Fluke clamp meter and the original alkaline cells luckily I caught it early and the contact damage was minimal.

Just curious what's that super cap for near the flat flex connector it's usually to preserve something like SRAM for a short time while you replace the batteries does this meter have a data logging function?

The 87-V sure doesn't.

[saturation]

... or use NiMH AA;AAA LSD cells as required, they rarely leak.  9V rarely leak too, but with increasing poor manufacturing by made in China you never know.  LSD cannot be made too poorly else the recharging and self discharging qualities would disappear.  A good charger would recognize the bad battery and reject it before it went too far bad.

Only 9V ruptures I've seen are occasional reports on the net.  Typically it pictures a failure of the 9v subcells to vent discharge byproduct gasses gently, leading to a subcell rupture, then a rupture of the 9v jacket.  If the subcells leaked without rapid gas discharge it often does so into the outer jacket and contains it from contaminating your powered device.

[frenky]

@Phil:
I was really happy to see that pcb is completely clean and that contact corrosion did not affect it.

@Bushougoma:

From what I have read online model 87 IV is completely different from other 87-? models. "87 IV" was later re-branded into Fluke 187.
87IV should have logging capability and also IR for safe serial communication with PC.

Super cap is Panasonic GC5.5V0.10F:


Full resolution:

[retiredcaps]

Modemhead has a Fluke 189 clean up blog at

http://mrmodemhead.com/blog/gallery/fluke-189-clean-up/

I purchased a Fluke 187 with corroded battery terminals as well.

https://www.eevblog.com/forum/chat/fluke-187-corroded-battery-terminals-how-to-clean/

I use Eneloops in my 187.  Alkaline will never be used.  Lithium is too expensive for me.

[tooki]

This is the reason why I try to avoid meters that take AA or AAA batteries and prefer 9 volt cell models. 9 volt cells are actually multiple AAAA cells inside a metal case which contains the crud when they leak I've yet to see an old 9 volt cell leak. Bulge sure but not leak.

Some use six AAAA cells, others use six flat rectangular cells in a stack.

[mzacharias]

This is the reason why I try to avoid meters that take AA or AAA batteries and prefer 9 volt cell models. 9 volt cells are actually multiple AAAA cells inside a metal case which contains the crud when they leak I've yet to see an old 9 volt cell leak. Bulge sure but not leak.

I have seen 9-volt types leak to the outside world, but I agree, not often. And not all 9-volt types uses AAAA's. I have seen some that use non-standard square, flat cells in series.

[Wytnucls]

Apparently they are not really AAAA. The cells are slightly shorter, by some 3.5mm.

[frenky]

Well that looks much better. 

Before:


After:


The white smudges on gray plastics are probably scratches because there is no way to clean it...

[frenky]

This will be the cleanest 87IV out there: 

[pelule]

How did you get the rupper case such clean again?
Have a Fluke 87, which likes to have the same...
/PeLuLe

[frenky]

First I tried with dish washing soap and it did not work.
Then I tried vinegar and baking soda and it also did not work.

Then I used sponge + hand cleaning paste for mechanics (from Aldi/Hofer) + brute force and got most of the dirt off.
After that I did another pass with isopropanol and now its very clean.

[frenky]

I had to finish up this one quickly so here are some photos:

[frenky]

And some measurements:

[SkyMaster]

Congratulation for giving a second life to this, previously abused, Fluke 87 IV.

 

[frenky]

Tnx.

I have also bought two different 2mm polycarbonate sheets for new screen protector which is broken.
One is "LEXAN CLEAR EXELL D" and the other is "LEXAN CLEAR 9030". Ebay: http://www.ebay.com/itm/2MM-LEXAN-POLYCARBONATE-SHEET-A5-SIZE-210MM-X-148MM-/121002572741

Replacing this broken plexi in front of lcd will be tricky because it's embedded into housing and sandwiched between two layers of plastics.

[SkyMaster]

Tnx.

I have also bought two different 2mm polycarbonate sheets for new screen protector which is broken.
One is "LEXAN CLEAR EXELL D" and the other is "LEXAN CLEAR 9030". Ebay: http://www.ebay.com/itm/2MM-LEXAN-POLYCARBONATE-SHEET-A5-SIZE-210MM-X-148MM-/121002572741

Replacing this broken plexi in front of lcd will be tricky because it's embedded into housing and sandwiched between two layers of plastics.

Are you planning to replace the clear plastic lens that is over the LCD display?

If this lens is fused to the front housing, I suspect that it could be difficult to remove and replace it.

I see that the lens is cracked in the upper right corner. If it was me, I would polish the clear plastic lens to improve it (if required), and for the crack; I would just live with it.

Mr. ModemHead, who is also active on the forum, is covering this on his own website:

http://mrmodemhead.com/blog/dirty-multimeter-clean-up

 

[Dr.Trinity]

very nice repair
Usually we throw meters away when they don't work anymore

[retiredcaps]

Usually we throw meters away when they don't work anymore

If you were in Canada, I would have you send me all the ones that don't work anymore especially if they are yellow or orange colored. 

Like your post below ...

https://www.eevblog.com/forum/blog/eevblog-933-keysight-u1272a-emc-issue/msg1178756/#msg1178756

[pelule]

How did you get the rupper case such clean?
I have a similar looking Fluke 87.
/PeLuLe

[frenky]

Are you planning to replace the clear plastic lens that is over the LCD display?

I was.

The plan was to drill a few holes into the lens and then try to wiggle out separate parts of the plexi.
And use hot-air to loosen any glue that might hold it.

But for now I'll just live with it.

I might still polish the lens with baking soda mixed with water...

[Smith]

The rubber case can be cleaned with IPA, very fast and easy.  Never had any side effects, still shines like new.

[Cerebus]

If it's just a crack in the screen, as it appears, you could seal it again with a solvent welding 'adhesive' for acrylic/polycarbonate judiciously applied through a fine, blunt hypodermic needle. You will need a tiny, tiny amount - one drop is often all it takes. That 'adhesive' (solvent really) will happily pull itself into that kind of crack by capillary action. Leave it to dry for as long as you can bear waiting, I'd suggest at least 48 hours. Might need a bit of polishing afterwards as it often spreads a little and hazes the area next to where it is applied.

[psykok]

How did you get the rupper case such clean?
I have a similar looking Fluke 87.
/PeLuLe

A good way to clean this cases is to use WD-40.
Looks strange but trust me it's working.

Alex