FLUKE 107 - absolute garbage lasted 2 years

[christian.burger]

I have a Fluke 107 that is giving me just above 30% error in my voltage, current, resistance readings.
I've asked an authorized Fluke repair center how can I calibrate it. They gave me a quote which is the price of a brand new one.
From what I could find, there's no way to adjust the readings, there' s no calibration mode or calibration procedure available for this model.
This is absurd in so many levels, so I wanted to vent a bit and find out if anyone faced this issue.
Also, just in case I'm wrong and someone knows how to calibrate manually, please let me know.

[mendip_discovery]

What did you do to the poor thing?

How do you know it's that far off?

You have tried new batteries.

[coppercone2]

if that dont help you can still do some basic checks like measure the power rail  voltage inside the device if you can find it, it might be as simple as a bad LDO or something. There is a chance its actually broken, not that it needs adjustment.


One part of the reason why some calibration is not recommended is because.. cheap asses will just "favor" the idea that the calibration drifted, not that there is a problem with the meter.

Software people especially. Reads 2V should read 6? it means add +4 to calibration duh

meanwhile the reference is bad and its providing like 1.5 instead of 2.5v and everything is totally whacked out


A sway bar thing fell off my lawn mower. I stopped for 30 min to find the bolt in the dirt and fix it. I can see the software guy duck walking around with his back at a 45 degree angle to keep the lawn mower steady so he can finish the job 


if fluke sees a 30% error in full scale, it means something is FUCKED. They gave you a parts replacement bill

[christian.burger]

@mendip_discovery: You made me laugh, thank you for that.
Yes, I replaced the batteries.
I'm not sure what happened, I've always treated with a lot of care...
I know it's that far off because I have other multimeters.

[christian.burger]

@coppercone2: You also made me laugh, thanks, and I see your point, even being now a software guy myself
It looks like now I have a yellow paper weight.
I will inspect a bit inside sometime also to see what I can find.
Hopefully you see how this is absurd, they offer no fix, no attempt to fix, just a replacement... and I don't even get a discount.

[coppercone2]

you need to look for burned out parts and if you can ID some chips see if the voltage is near where you think it should be.

A CRACKED solder joint can cause big error too. Its handheld, that stuff gets cracked joints

[xrunner]

A sway bar thing fell off my lawn mower. I stopped for 30 min to find the bolt in the dirt and fix it.

Dude get a magnetic pickup tool from Harbor Freight - I have one it's a lifesaver. 

https://www.harborfreight.com/long-reach-magnetic-pickup-tool-with-quick-release-93950.html?_br_psugg_q=magnetic+pickup+tool

[coppercone2]

oh yeah i have that but it did not work for some reason. it fell into a clump of grass, it would need to be dangerously strong. that is good tool for cleaning wire brush strands after angle grinder or bench wheel.

[xrunner]

oh yeah i have that but it did not work for some reason. it fell into a clump of grass, it would need to be dangerously strong. that is good tool for cleaning wire brush strands after angle grinder or bench wheel.

I dunno what brands you have tried but that one I linked has a crazy strong magnet that will pull a nail or nut from a clump of grass ... but back to your topic. 

[Kleinstein]

When such a meter is off calibration, there is a reason to it and it needs more than just recalibration / adjustment (maybe except for the rare case of lost / faulty cal data).
Just a readjustment would only gove you an unreliable meter that has a good chance to drift even further.
With most lower cost handheld meters a repair is not really sensitble: unless there is a known weakness typical defect the cost of the repair can get too high. Part of the problem is cleaning the board after soldering. Also the calibration after a repair is relatively expensice compared to the costs of the meter - with handheld one it often need someone to actually more the switch.

The Fluke quote for a "repair" is close to a new meter, because you would likely get a new meter (maybe less the probes).

[Arhigos]

I believe there is cal button in the battery compartment. But if its 30% off you probably have some hardware failure.

Also, calibration mode is for service centers, calibration labs, etc. Not for regular owners.. That applies for any brand of test equipment

[rsjsouza]

As others have hinted, carefully inspect the interior of your meter for any faults.

My experience with its sibling Fluke 101 was very disappointing and hinted to a lower degree of quality control. If the 107 is similar, I wouldn't be surprised that yours could have been a victim of the same reason.

https://www.eevblog.com/forum/blog/eevblog-1574-is-the-$42-fluke-101-multimeter-any-good/msg5152701/#msg5152701

Good luck in your repair!

[Simon]

Don't confuse sending something for calibration with having it adjusted. Sending something for calibration generally means that it will be tested and you get a pass fail with a detailed report. They will not adjust it for you. As others have said if it is 30% then something in badly wrong. If it were out by twice as much as it is supposed to be then yea maybe it needs a nudge, but 30% is faulty.

[coppercone2]

even from the factory its super suspicious if its 30% error. They will have 1% resistors in there or better and a reference that is pretty accurate.

I don't think it can even be lost cal data for 30%, it must be faulty cal data (bad chip giving bizzaro numbers), and I am surprised the program does not say "this is outside the bounds of adjustment for the chip".

I think it must be a analog problem. The cal just brings the cheapish analog circuit from say 5% intrinsic accuracy to 0.1% accuracy. 30% is extreme

the cal is a virtual version of the litle adjustment screw you have in your dial gauge. In this case the dial gauge is bent IMO

[shapirus]

But hold on, just 2 years? Should it not be still covered by warranty?

[J-R]

Warranty is 1 year on the 107, at least in the US: https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/pocket-107

[christian.burger]

Thanks, that actually helped, I found some 4 contact pins for calibration.
There is a calibration window beneath the battery compartment, which accesses 4 gold plated pads in PCB
(WP9, WP8, WP7, WP6).
I have no idea how to use them though, does anyone know?

[TomKatt]

I’m no expert, but I can’t believe the issue is as simple as calibration…. 30% deviation is pretty substantial - there must be a hardware fault somewhere.  Even if you were able to correct the reading by some calibration routine, I don’t think that I’d ever trust that meter again.

[EggertEnjoyer123]

As others have said, the chance that this is a software error is pretty much zero. I would not mess with the calibration at all.

You’ll have to open up the meter. If everything is off by the same amount, it is probably the voltage reference.

[Arts]

The most common failures that I have found in Fluke meters involve the components in the input circuitry. Over-voltages/transients/spikes are usually responsible.
Oftentimes, these components will only act up after a certain voltage level is applied, but can also cause problems regardless of operating conditions.

I would think that this model has a very similar input arrangement as the usual Fluke meters, so I would suspect the following:

Varistors, Spark Gap, Input Resistors.

[floobydust]

These small Flukes, they deleted the usual protection zener-connected transistors.
So I don't expect them to be robust in certain situations. Not the same protection despite the familiar parts such as surge resistor, PTC, MOV's.
TVS D1 is across the battery so the BAV199 CR1 might dump overvoltages there - still a terrible idea.

[joeqsmith]

These small Flukes, they deleted the usual protection zener-connected transistors.
So I don't expect them to be robust in certain situations. Not the same protection despite the familiar parts such as surge resistor, PTC, MOV's.
TVS D1 is across the battery so the BAV199 CR1 might dump overvoltages there - still a terrible idea.

My Fluke 107 survived five positive and negative 14kV 100us full width half height transients through a 2 ohm source.  Very few meters I have looked at would survive that level.  While the 107 was eventually damaged at 15kV, I was able to repair it and it is still fully functional today.   Sadly I can't say that about many of the meters I have looked at and they get recycled. 

It's not even a question of cost.  I have a Fluke 101 that has yet to be damaged with all my testing and it cost less than $50.  Consider I ran a Keysight U1282A that was closer to $800 which couldn't survive the same levels as my cheap Amprobe AM510.   And with all the custom parts, it could not be repaired.   

[coppercone2]

lol I got it. Calibrating a 30% error with software is like if a dial gauge not reading right, so you take it apart and paint over the scale.

I seen that before when its really underfunded. You get sharpie marks that indicate where the real value is. Then they assume its still linear.

Then the employee training is like how to understand managers sharpie marks.

Like a mark on the 5 psi mark that says 30. So you rescaled a reading of 5 psi to indicate 30 psi. Clearly does not need to be replaced.

The magic of the look up table (just assume its still linear )

[factory]

Was there any battery leakage from the previous set of batteries?

David

[christian.burger]

Yes, there was battery leakage and I've reconstructed the terminals. It's working fine other than the readings which are off, but also I don't think that is related to the problem, unless you know something specific about that.
I agree that it's most likely toast, but would like to try and use the calibration terminals just to see what I can get before I throw it away.
I could not find any reference to the WP9, WP8, WP7, WP6 calibration terminals anywhere.