Fluke 87V screen goes crazy with WIFI & Cell phone signals

[Twistx77]

Hi,

Today I was measuring some stuff with my 87 and suddenly the screen went crazy (turned on and off quiclky) I thought there was something wrong with the MM but then I moved and it went back to a normal state. I figured it was my router which was like 20 centimeters away from the MM.

Then I tried to get it close to my cell phone and make a call and it could pick up the signal from 40 cm away.

I thought that at least the WIFI signal wasn't strong enough to interfere with the MM. How reliable can this MM be close to a 2kW motor for example?

 

[Kiriakos-GR]

The only MM type that RF has an very minor effect on it , its the analog ones .

[Mambo]

How reliable can this MM be close to a 2kW motor for example?

Very....you should be using the low pass filter mode. Decent meters have a wide AC input typically 100kHz (still well below what I'd expect your router to be outputing) which allows noise to appear. Cheap meters due to limitations normally only show AC voltage upto 500Hz and this is where problems can arise.  Many meter's have issues with motors and noise, normally from Pulse Width Modulated Drives (also known as Varaible Speed Drives). I can't talk for noise from Routers, but good practice is to use the low pass filter in any area that has other sources floating around. Lesser meters don't have that function, but to be honest they often don't need it because they can't see the higher frequency voltages anyway. This is not a fault of the 87-V, it actually highlights how good they are...but it can have it's downside.

Is it possible that you have a noisy switchmode power supply within thr router or other causing the noise, as the RF output of the router is not the likely cause imo.

 

[JohnS_AZ]

Wow, a whole new course of tests for Dave to do with all of his multimeters. :-)

[Kiriakos-GR]

Wow, a whole new course of tests for Dave to do with all of his multimeters. :-)

About what ?   Testing RF interference ..

If so , i would make the challenge larger ,
and I would suggest the DMM to be tested next to TV and Radio  ( UHF - FM  band ) transmitters  with RF output  of 2 - 20 KW  ..      

[Twistx77]

Very....you should be using the low pass filter mode. Decent meters have a wide AC input typically 100kHz (still well below what I'd expect your router to be outputing) which allows noise to appear. Cheap meters due to limitations normally only show AC voltage upto 500Hz and this is where problems can arise.  Many meter's have issues with motors and noise, normally from Pulse Width Modulated Drives (also known as Varaible Speed Drives). I can't talk for noise from Routers, but good practice is to use the low pass filter in any area that has other sources floating around. Lesser meters don't have that function, but to be honest they often don't need it because they can't see the higher frequency voltages anyway. This is not a fault of the 87-V, it actually highlights how good they are...but it can have it's downside.

Is it possible that you have a noisy switchmode power supply within thr router or other causing the noise, as the RF output of the router is not the likely cause imo.

 

I understand that it could pick up noise from a motor and give you a miss reading. That's when the low pass filter would be helpful the problem is that I don't get a miss reading but the screen just turns or and of or shows a "----" reading.

Also I've test the issue with my own cell phone since the first time was with anothers person cell phone and I think both times I saw the problem was only the cell phone and not the router and the cell phone since both were in the same table and I tried today with my own router and it doesn't happen anymore. Also I tried with my own cell phone and it doesn't happen " as much" as before, only when I have my cell phone like 5 cm away, if I take it farther it doesn't happen.

[Mechatrommer]

so the Fluke87 is not so that undestructable huh? they should design a EMI proof DMM, the Fluke 88 or something and "double the price" of Fluke87! then we will get a super high end super reliable super everything DMM.

[Kiriakos-GR]

so the Fluke87 is not so that undestructable huh?

Personally I do not accept as fact , an single report about an such issue ...
Specially with out an proof .. picture or video ..  

There is people who do the maintenance of very powerful re-transmitters (non cable TV systems ),
no one had report an issue so far .

Mobile phones operate at 1G and above ..

Every DMM have inner frequency clocks ,  an instant interference its not the end of the world . 

[Kiriakos-GR]

Also I tried with my own cell phone and it doesn't happen " as much" as before, only when I have my cell phone like 5 cm away, if I take it farther it doesn't happen.

What brand and model is it ?? 

[Mambo]

I understand that it could pick up noise from a motor and give you a miss reading. That's when the low pass filter would be helpful the problem is that I don't get a miss reading but the screen just turns or and of or shows a "----" reading.
Also I've test the issue with my own cell phone since the first time was with anothers person cell phone and I think both times I saw the problem was only the cell phone and not the router and the cell phone since both were in the same table and I tried today with my own router and it doesn't happen anymore. Also I tried with my own cell phone and it doesn't happen " as much" as before, only when I have my cell phone like 5 cm away, if I take it farther it doesn't happen.

Twistx77, I ask again are you using the 87-5's low pass filter when this happens...

[Kiriakos-GR]

What low pass filter had to do , with any interference at the DMM display ?   

[alm]

so the Fluke87 is not so that undestructable huh?

How was the DMM destructed?

they should design a EMI proof DMM, the Fluke 88 or something and "double the price" of Fluke87! then we will get a super high end super reliable super everything DMM.

Nah, they'll just offer you a free bumper .

I would expect some EMI immunity, though not perfect. Interference from 40cm with a cell phone sounds pretty bad, though.

[Kiriakos-GR]

I believe him ... I just damaged my 87-5

The problem stands when the mobile phone transmits ,  the display it does flashing like crazy ..
Random  fixed  labels appear .

The left side its the most unshielded ...  

I got my mobile ( was on call )  close to the range switch , and the display stopped working ,
got blank ...

I switched the meter  off  and on , boots but with an error ..
I am suspecting  that the software of it , become corrupted ..  
I need to go to sleep , its late up here , I will let it with the battery removed all night ,
and see if it will recover ..

If not .. I will have to find out the true face of Fluke support , at a minimum damage of 40 EUR just shipping cost ..

More about it , tomorrow ..  
Pictures as always ..

[PetrosA]

Can anyone narrow it down to GSM vs. 3G and what frequency?

[Kiriakos-GR]

Can anyone narrow it down to GSM vs. 3G and what frequency?

There is no many heroes around, to do such tests ...

My phone was set in manual to operate at standard GSM , as the 3G network its not powerful in my location,
and the continuously search for 3G network , it was killing my battery run time.

Now, about me and the DMM, it looks that I got in deep shit .
I contacted two service centers in Greece   , contacted Holland and England .
The two Greek Fluke centers , asked me pictures and proofs of the problem so to inform Holland .

Holland forward my email in to a third " Dealer " who contacted me saying that ...
I have to send the DMM to him ,  he will send the DMM to Holland ...
If Fluke in Holland  decides that its not an damage caused by the user ,
it will by repaired for free .. and shipped back for free too ..

If not , the shipping cost and just the inspection it will had an cost of 150 EUR ..

I am calm , but I will hunt down Fluke even in Court , if they do not act in good faith ..

Its a fact .... your GSM mobile it can trash your FLUKE 87-5  !!

This is an ridicules cause of damage , totally undocumented and a good reason for fight ..

Today at work , we got an small  Mastech DMM ( of value 15$ ) and we set four GSM phones ( calling  its  other = all active transmitting )   next to it , and it survived and works great.    

I am going to send it , and hope for the best .
I do not like even to think what it will happen if they did not recognize this issue as their fault,
as I said, I will start my personal war against them ..  

[Kiriakos-GR]

wondering and made a test on my Uni-T. i think its EMI passed, with or without the probes connected. this is a big issue IMO. some of our fellas here have caught Fluke "pantless" or "pantyless"

The attachment looks damaged , I can not download the file ..

Yes, thats an ultra major flaw  for the specific model , the Fluke 87-5 ..
And some one , needs to give allot of explanations about it ..  

[Mambo]

 Mastech DMM FTW....wow who would have thought it. I'm glad I never tested my 87-V, as claiming warranty might be a problem.

[saturation]

Revealing thread, if 'Err' appears on the 87V, it can mean the EEPROM has been corrupted!

K, given you are most affected, have you tried the system status check procedures?  Download the 87V service manual and try the test procedures beginning on page 14, you have nothing to lose.

Report back whatever you find please.

To start, press & HOLD down AUTOHOLD button, then turn the rotary switch to any position from OFF.  The LCD will show all functions on, you rotate from function to function, I forget the sequence, but it should show, light up all LCD annunciators, firmware version number, meter number, etc.,then you can proceed with the other tests.

You can also RESET the 87V, just go through the password reset procedure in the manual.

[Kiriakos-GR]

The attachment looks damaged , I can not download the file ..

database error sh*t was happening and the attachment might got scrambled! here again.

Hey tester    the mobile should be on calling mode , not stand-by .

Edit I can not see clearly the screen , does it call some one ?

[Kiriakos-GR]

Hi saturation  , I will try the tests ... I have nothing to lose .

About the reset , it is only documented as Password reset ... nothing more ..
Any way I will do my homework , and I will post soon my findings .

Thanks for the help, I do appreciate it .

[jahonen]

I'm quite amazed that mobile phone really did permanent change to the DMM. I have seen many times that things go berserk in EMC RF-immunity testing (conducted or radiated) but there has been usually no permanent damage, just temporary malfunction. However, probably no real hardware damage but just some corrupted configuration memory (CPU went berserk and corrupted vital data).

Regards,
Janne

[Kiriakos-GR]

Ok , I did my best about testing , my fast reply will be , that I have lost the firmware ...

The indication F8- translates to  Boot-rom F8X = active .
Normally the DMM posts like F87 and power on ..

The Missing  F87 looks to be the specific firmware , that the specific DMM uses .
And I say " The specific  DMM "  , simply because  the same Boot-Rom IC   it can be used in many Fluke models ..  exactly the same chip as hardware ..

Now , the boot-Rom by it self , holds active some part of software used for diagnostics , like display light - battery status - display status .... all those are working .

The next step for the multimeter after the ROM test , are to load the specific firmware for the Fluke 87-5 .
My firmware got corrupted , there is possibly an file size change to it ,  and the Boot-Rom identifies it and posts  ERROR .

I have awareness of what happens inside it ,  but it looks that there is nothing for me to do about it.

On a second note , the DMM has on the Boot-Rom, storage'd data , like last calibration log and such,
if those got messed up , Fluke will have knowledge about it , and it will cancel the warranty.

I got informed that if everything goes well , Fluke will provide to me another 6 months warranty on a signed paper .


On a third note , I would love to had the choice to reset it , if there is an such progress ,
if some one has an solution , and does not like to write it in public , just use an Private Message ..
 


 

[PetrosA]

I offer my sympathies to you guys! This really sucks and now that Kiriakos has a bricked 87V it's hard not to believe it.

I would hope that Fluke addresses the issue. I can certainly imagine situations where you have your meter on at work, get a phone call, put it on speaker and hold the phone near the meter, or lay the meter and your phone on a counter or bench and talk to someone while taking readings. If a simple GSM signal from a phone can brick a really expensive meter, someone didn't do their testing thoroughly enough. If it's not specific to GSM, would a walkie talkie do the same thing (strong signal burst)?

P.S. some sick, self-destructive part of me wants to test my Agilent, but the more developed part of my brain is holding me back

[EEVblog]

Damn, that's serious!
I would have expected the 87V to be fairly immune to EMC, but I'm not entirely surprised a high power RF source can upset it.
But to permanently brick it?, that's really unacceptable.

I'm led to believe the 87V Ex model has added EMC shielding, but I can't find details on that.

So we have one case of interference by WiFi, and another of bricking by mobile phone. This doesn't sound like a 1-off.

Should I attempt to test the susceptibility of mine? 

Dave.

[MrPlacid]

Should I attempt to test the susceptibility of mine?  

Dave.

Man, it's like Toyota all over again.

Dave, test your DMM and remember to take video. I bet fluke will replace yours free of charge since you're well respected in the DMM community.