Fluke 187 corroded battery terminals - how to clean?

[retiredcaps]

Also posted on eevblog where most of the multimeter people hang out, but I want to get more opinions and suggestions from people here.

I bought this used Fluke 187 off ebay. Opening up the battery compartment reveals some past battery leakage/corrosion. The supplied batteries are not leaking and are Duracell Procell with expiry date 2017.

I have read about using baking soda and vinegar to neutralize the corrosion as per

http://www.eevblog.com/forum/beginne...ked-batteries/

So I applied the mix using a q-tip, but as you can see, there is still corrosion (the two middle cell holders)? Is it just a matter of applying more of the mix over and over again? Ideally, I would like to "soak" the entire back case overnight, but I'm afraid of damaging or staining the case.

I don't *think* the main pcb was affected by the corrosion due to the design of the back plastic casing. I can't detect any corrison on the main board. All the rotary functions seem to work correctly.

I want to make sure there are no long term problems as I expect this multimeter to last a long time. I will be using nimh batteries for this Fluke 187.

Suggestions are welcome.

[ratdude747]

Re: Fluke 187 corroded battery terminals - how to clean?

The meter should be ok, electrolyte is only conductive as a liquid (not a crystallized salt). As for the batteries, who knows... I'd try the meter with some fresh alakalines before I risked some NiMHs on it.

[t.j.]

Re: Fluke 187 corroded battery terminals - how to clean?

emery cloth an a small screw driver, the baking soda vinegar neutralized it, can clean it with the emery an a small screw diver.

[ratdude747]

Re: Fluke 187 corroded battery terminals - how to clean?

Baking soda is for acid batteries. Duracell Procells are alkaline batteries. Baking soda is not of use.

if it's dried already, it shouldn't be of electrical concern, see my post above.

[999999999]

Re: Fluke 187 corroded battery terminals - how to clean?

Both of those battery contact strips are removable. There may be a little tab that needs depressed or rebent to provide tension again when you reinstall them. Pull them off, agitate the plastic casing in hot detergent solution and briefly scrub with a toothbrush, rinse, shake remaining water out, and air dry.

Probably was alkaline batteries that leaked, you could try applying a mild acid to the contact strips then polish the metal with a toothbrush and metal polish or use fine sandpaper. As a last step if you happen to have any, you could very lightly tin the contacts with silver solder, though if you apply too much they won't fit back in the casing so in the worst case just heat the contacts and fling excess solder off while molten. Retinning the contacts isn't really necessary but it may be a longer lasting fix that way as the bare metal can oxidize again.

Depending on the contact size and perhaps your ability to whittle, you might be able to get replacement contacts to fit. Either contact Fluke to see if the parts are available or places like Digikey have a few random styles though I don't know which are most compatible.

http://www.digikey.ca/product-detail...209K-ND/299941
http://www.digikey.ca/product-detail...210K-ND/151586
http://www.digikey.ca/product-detail...209K-ND/151583
http://www.digikey.ca/product-detail...90K-ND/2137886

[budm]

Re: Fluke 187 corroded battery terminals - how to clean?

I use the car batteries terminal corrosion protection that you spray on the car batteries terminal, I just spray it on q-tip and rub on the batteries area, so far so good on most of my equipment that are damaged by leaking batteries.

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

@ratdude747
As always, thanks for the comments and hints.

@t.j.

Thanks for the suggestions regarding the emery and screwdriver. PS. Where is wonk, AB?

@999999999

I didn't know replacement parts existed, but Excavatoree over at eevblog mentioned they were available.

However, they are $9.56 EACH (ripoff).

http://www.ebay.com/itm/370609154201

The seller also doesn't ship outside USA.

So I will look through digikey for a possible replacement.

@budm

Check your Fluke 187.

Previously, I purchased a Fluke 87IV which is essentially the same as a 187, but the seller completely didn't bother to test it and listed it as working. When I got it, the most basic functions didn't work. I opened it and found that the battery compartment has signs of leakage/corrosion and it got onto the main pcb.

So I don't know if the 187/189/87IV are prone to corrision or not? Or am I just unlucky? I have purchased other used Fluke multimeters before and never had battery corrosion problems.

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

So thanks to all the helpful suggestions and comments, I ended being able to get the contacts out thanks to a-fluke's ebay auction photos. I couldn't see the "hidden" tabs late last night and it has been cloudy all day.

I was able to get the worst corroded contact out without any damage and let it soak in vinegar for about 1 hour. Then I neutralized it by adding baking soda and let it sit for about 30 minutes. Then I gave it a wash with tap water (I don't have any distilled at home).

Here is the result. Do you think it is the best I can do given the tools (vinegar, baking soda, toothbrush)?

I wasn't able to remove the other not so badly corroded contact for fear of damaging it so I left it alone and tried my best to use a toothbrush/q-tip.

PS. I have a reminder now to check my batteries in all my multimeters every 6 months.

[Evil Lurker]

Re: Fluke 187 corroded battery terminals - how to clean?

I would definitely hit them with some emery cloth or fine grit sandpaper or something to brighten them up a bit.

[smason]

Re: Fluke 187 corroded battery terminals - how to clean?

Personally I always use mechanical means (scrape with a blade, then fine-grit sandpaper) rather than chemicals.

[budm]

Re: Fluke 187 corroded battery terminals - how to clean?

That is pretty good clean up jobs, may be you can coat it with Silicone grease.

[999999999]

Re: Fluke 187 corroded battery terminals - how to clean?

They are clean enough except that I would use mechanical means to further clean the area of contact with the batteries like very (VERY) fine grit sandpaper then a metal polish. Same goes for the contact(s) still in the meter housing.

[Kiriakos GR]

Re: Fluke 187 corroded battery terminals - how to clean?

As for the batteries, who knows... I'd try the meter with some fresh alkaline before I risked some NiMHs on it.

Recently I have updated my research over NiMH, due my experiences with many different brands and models of NiMH, I love digital photography and so I am big spender about AA NiMH.

Half of my story is here. http://www.ittsb.eu/mini_articles.html#SanyoEneloop

What I consider as good news, and it would also be one direct suggestion to retiredcaps, would be to try out those latest Sanyo Eneloop HR-3UTG-4BP,
that are capable to keep their 75% of charge even for three years.

Personally I have just receive 8xAA & 8xAAA so to use them exclusively in expensive multimeters.

With those batteries, there is no chance to have a corroded battery contact ever.
This new generation of eneloop it will kill the market share of alkaline in just few months from now.

This is my wild guess.

[budm]

Re: Fluke 187 corroded battery terminals - how to clean?

I also use Eneloop in my Digital camera which is great, but when use them in my 187, since 4 of them is = 4.8V full charge, the batteries warning keep coming up.

[Krankshaft]

Re: Fluke 187 corroded battery terminals - how to clean?

I have a bunch of Eneloops they're great batteries and have a real low self discharge rate.

Unlike the other brands that will self discharge in a few weeks if you don't constantly recharge them.

They have a 6 hour charge time but the slower charge rate is gentler on the batteries. As a result they can go through more charge / discharge cycles than the quick charge batteries. Stay away from the 15 minute charge batteries the rapid charging destroys them pretty quickly.

If you need a noisy fan to keep the cells cool during charging they're not going to last very long .

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

I also use Eneloop in my Digital camera which is great, but when use them in my 187, since 4 of them is = 4.8V full charge, the batteries warning keep coming up.

I just put in some eneloops (taken from my Canon A80) into the 187 and they work fine with no battery warning. All 4 eneloops measured 1.2655V DC. When they are fully charged the eneloops can read as high as 1.501 fresh off the charger.

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

Half of my story is here. http://www.ittsb.eu/mini_articles.html#SanyoEneloop

Yes, I saw that when your site came alive. Congrats on the new site.

I have been a very long time nimh battery user.

[budm]

Re: Fluke 187 corroded battery terminals - how to clean?

I wonder what is the set point for the batteries warning point is, and how accurate the meter will be with low batteries.

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

Dave Jones, Kiriakos GR, and Martin Lorton do a lot of multimeter testing and one of their "standard" tests is to connect a variable DC power supply to the multimeter. The multimeter is then set to measure some precision component (resistor or some DC voltage). They turn down the power supply until the low battery warning comes on and they see if the multimeter is still within spec or not.

I'm fairly sure all the modern Flukes will display "batt" and won't let you take a reading well before they are out of spec.

I just got a Fluke 27 and it came with a weak battery. It displayed the low battery indicator and I did a simple shorting out of the probes. The readings wouldn't settle and fluctuated. I thought I got a dud Fluke 27.

However, I put in a fresh battery and got 0.2 ohms when shorting out the probes. So for the Fluke 27, the multimeter allows you to take readings with a low battery indicator with possible erroneous results.

I think the "batt" is definitely the way to go. You don't want your multimeter showing 0V DC only to find out the big filter capacitor is still charged at 400V DC.

A lot of people don't appreciate this small nuance.

Martin's multimeter reviews
http://www.youtube.com/playlist?list...6&feature=plcp

Dave Jones
http://www.eevblog.com/episodes/

Kiriakos
http://www.ittsb.eu/index.html

PS. I didn't realize how BIG the Fluke 27 is. I have always seen pictures and knew it was made for the US government and military, but until I got it in my hands, I had no idea how hefty it is.

[retiredcaps]

Re: Fluke 187 corroded battery terminals - how to clean?

I wonder what is the set point for the batteries warning point is, and how accurate the meter will be with low batteries.

If you have time, hookup the Fluke 187 to a variable DC power supply.