Author Topic: External battery box for Fluke 17B  (Read 1129 times)

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Offline max.wwwang

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External battery box for Fluke 17B
« on: March 27, 2020, 08:33:24 am »
The copper contacts of its internal battery box were corroded by battery leaks when it was sitting idle. I soldered a pair of wires and tied them up to an external battery box. All have been properly done, electrically and cosmetically. But with a new pair of AA batteries, I constantly have this low battery icon and sometimes refusing-to-work all black LCD segments.

The only difference I can think of is the resistance of the wires. But would that be so significant?
 

Offline Fungus

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Re: External battery box for Fluke 17B
« Reply #1 on: March 27, 2020, 08:39:36 am »
But would that be so significant?

No, not at the currents a multimeter will draw.

PS: You could always try measuring it...
 

Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #2 on: March 27, 2020, 08:49:46 am »
No, not at the currents a multimeter will draw.

PS: You could always try measuring it...

What's the cure then?
 

Offline tautech

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Re: External battery box for Fluke 17B
« Reply #3 on: March 27, 2020, 08:56:30 am »
Get some nickel strip like they use to spot weld battery packs together and fashion a new set of battery contacts for the original holder.
I use a 15B and just changed batteries yesterday and IIRC they are pretty basic so should be easy to make.
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Offline The Soulman

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Re: External battery box for Fluke 17B
« Reply #4 on: March 27, 2020, 09:03:28 am »
Warning! Danger!

The battery back isn't electrically isolated from the meters inputs!
i.e. probing mains will cause the battery to become live!
 
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Offline Fungus

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Re: External battery box for Fluke 17B
« Reply #5 on: March 27, 2020, 09:06:17 am »
What's the cure then?

I dunno. You'll have to start measuring things to find where the problem is, eg. what's the voltage at the PCB?

You do have a second multimeter, right? If not, start there.
 

Offline tautech

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Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #7 on: March 27, 2020, 09:10:10 am »
Get some nickel strip like they use to spot weld battery packs together and fashion a new set of battery contacts for the original holder.
I use a 15B and just changed batteries yesterday and IIRC they are pretty basic so should be easy to make.

I think I did that previously without a satisfactory outcome - Can't remember if that was because of poor workmanship or not. Sounds like I have to tear off these nicely tied wires and battery box since it's a pain having to reply on luck using it.

Warning! Danger!

The battery back isn't electrically isolated from the meters inputs!
i.e. probing mains will cause the battery to become live!

This is a good reason of reversing my good effort of doing this. Thanks.
 
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Offline The Soulman

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Re: External battery box for Fluke 17B
« Reply #8 on: March 27, 2020, 09:12:50 am »
As in why its not working,

*the battery's are actually near empty
*a bad solder joint (soldering on corroded wire?)
*some battery holders and battery combinations have size compatibility issue's and have no proper force on the contacts.

Could you measure the voltage (when switched on) on the pcb with another meter?
Does continuity measurement work?
 


Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #10 on: March 27, 2020, 09:15:17 am »
As in why its not working,

*the battery's are actually near empty
*a bad solder joint (soldering on corroded wire?)
*some battery holders and battery combinations have size compatibility issue's and have no proper force on the contacts.

Could you measure the voltage (when switched on) on the pcb with another meter?
Does continuity measurement work?

All connections are soldered. Continuity works when it's working.
 

Offline The Soulman

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Re: External battery box for Fluke 17B
« Reply #11 on: March 27, 2020, 09:17:40 am »
Get some nickel strip like they use to spot weld battery packs together and fashion a new set of battery contacts for the original holder.
I use a 15B and just changed batteries yesterday and IIRC they are pretty basic so should be easy to make.

I think I did that previously without a satisfactory outcome - Can't remember if that was because of poor workmanship or not. Sounds like I have to tear off these nicely tied wires and battery box since it's a pain having to reply on luck using it.

Warning! Danger!

The battery back isn't electrically isolated from the meters inputs!
i.e. probing mains will cause the battery to become live!

This is a good reason of reversing my good effort of doing this. Thanks.

I've had a meter like this for years but only used it for low voltage near the bench and work on cars,
had multiple layers of insulation tape as I didn't wanted to cause a short thru the metal body of the car..
 

Offline retiredcaps

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Re: External battery box for Fluke 17B
« Reply #12 on: March 27, 2020, 06:58:09 pm »
The copper contacts of its internal battery box were corroded by battery leaks when it was sitting idle.
After any leakage, I suggest a thorough IPA cleaning with a clean toothbrush of the entire board. Sometimes the leakage wicks its way onto other components that are not visible to the naked eye.  Let it dry completely overnight or use a PC fan to dry it for a few hours.

If you have a DC power supply, set it to 3V and see what the current draw is.  Or measure the current draw using another multimeter.

Many of us are now using low LSD nimh cells like Eneloops instead of alkalines in meters.
 

Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #13 on: March 27, 2020, 10:52:59 pm »
After any leakage, I suggest a thorough IPA cleaning with a clean toothbrush of the entire board. Sometimes the leakage wicks its way onto other components that are not visible to the naked eye.  Let it dry completely overnight or use a PC fan to dry it for a few hours.

If you have a DC power supply, set it to 3V and see what the current draw is.  Or measure the current draw using another multimeter.

Many of us are now using low LSD nimh cells like Eneloops instead of alkalines in meters.

Yes, that's what almost always happens. I did clean as thoroughly as practicable, though only with a damp cloth (was too frugal to use IPA!).

Does this imply it would work, except for the hazard (which I can manage in an alternative way), if with Eneloops? Thanks.
 

Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #14 on: March 27, 2020, 10:57:28 pm »
I've had a meter like this for years but only used it for low voltage near the bench and work on cars,
had multiple layers of insulation tape as I didn't wanted to cause a short thru the metal body of the car..

Yes, I only recently realised it's only a Cat.II meter - I had no idea about the Cat's when buying it. Anyway, I would not use it for higher than 240V AC.
 

Offline max.wwwang

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Re: External battery box for Fluke 17B
« Reply #15 on: March 28, 2020, 02:28:30 am »
Had another check, resoldering and desoldering, cleaning and checking again. Eventually, I found a trace behind the Nickle spring was open (with some trace of copper oxide here and there). Cleaned with acetone (have no alcohol in stock, no IPA as well - had run out and I didn't do panic shopping), cut the unneeded part of the contacts (to avoid bending stress), and soldered the contact/trace and wires, tidied everything up again. Now in perfect order, bingo!
« Last Edit: March 28, 2020, 02:33:57 am by max.wwwang »
 


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