Author Topic: Fluke 289 does not turn on -> blinking green power button  (Read 6349 times)

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Offline GeoffreyF

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #25 on: January 13, 2019, 05:02:30 pm »
Your link goes to something my computer detects as a virus.

Mind explaining what is there at your link?  Why should anyone click it?
US Amateur Extra W1GCF.
 

Offline ElecSeb

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #26 on: January 13, 2019, 08:44:16 pm »
Just a normal page regarding end of internet, is around for ages (and often used)...

Page can be opened with any browser and tested with, KIS & Norton, so kinda curious what virus scanner/internet security you have...
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #27 on: July 29, 2019, 09:57:03 pm »
Hi all,

I was just pointed to this thread, as it seems I am in the same situation as everyone else here: all three caps, C46, C55 and C92, measure short across their terminals (and are all tied to the battery negative - let's call it "ground" from this point onwards).
First, as I commented in the other thread, I find it strange for capacitors so spread out on the board to all exhibit this issue (not a an issue with the caps themselves, but an issue affecting them) and also in most cases with a dead Fluke 289.
Maybe they are all connected to the same power rail or data bus (and that somehow gets shorted whenever the NXP goes bad)?
Someone here mentioned they removed the NXP from the board and the short went away.
Can you please confirm that, with the NXP removed, the non-"ground" terminal of each of these three caps are linked to one another?

Also, is it just me but, having a really quick read of the NXP datasheet, it doesn't seem to have an internal storage?
If so, could we not just remove the dead NXP and replace it with a brand new one?

Thanks!
 

Offline Per Hansson

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #28 on: July 30, 2019, 08:36:38 am »
Also, is it just me but, having a really quick read of the NXP datasheet, it doesn't seem to have an internal storage?
If so, could we not just remove the dead NXP and replace it with a brand new one?

Thanks!
I agree, it seems that the RAM is in separate IC's U25 & U27 and Flash is in separate IC U28, here is a review with high-res photos:
https://lygte-info.dk/review/DMMFluke%20289%20UK.html
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #29 on: July 31, 2019, 06:35:35 am »
I agree, it seems that the RAM is in separate IC's U25 & U27 and Flash is in separate IC U28, here is a review with high-res photos:
https://lygte-info.dk/review/DMMFluke%20289%20UK.html

Hmm... I suspect the challenge here is the reballing of the replacement NXP chip.

Nice, comprehensive review, BTW.
 

Online mzacharias

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #30 on: July 31, 2019, 04:26:05 pm »
Hi all,

I was just pointed to this thread, as it seems I am in the same situation as everyone else here: all three caps, C46, C55 and C92, measure short across their terminals (and are all tied to the battery negative - let's call it "ground" from this point onwards).
First, as I commented in the other thread, I find it strange for capacitors so spread out on the board to all exhibit this issue (not a an issue with the caps themselves, but an issue affecting them) and also in most cases with a dead Fluke 289.
Maybe they are all connected to the same power rail or data bus (and that somehow gets shorted whenever the NXP goes bad)?
Someone here mentioned they removed the NXP from the board and the short went away.
Can you please confirm that, with the NXP removed, the non-"ground" terminal of each of these three caps are linked to one another?

Also, is it just me but, having a really quick read of the NXP datasheet, it doesn't seem to have an internal storage?
If so, could we not just remove the dead NXP and replace it with a brand new one?

Thanks!

I know this is crude, but it often works to feed a power supply at an appropriate voltage, and current limited as necessary, into the short, and simply wait a bit and see what gets hot.

If it's a true 0.0  Ohm short, then sure, no heat can be generated, but that's actually fairly rare.

I've found numerous bad microprocessors, chip caps, shorted tantalums, etc this way.
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #31 on: July 31, 2019, 07:56:29 pm »
I know this is crude, but it often works to feed a power supply at an appropriate voltage, and current limited as necessary, into the short, and simply wait a bit and see what gets hot.

If it's a true 0.0  Ohm short, then sure, no heat can be generated, but that's actually fairly rare.

I've found numerous bad microprocessors, chip caps, shorted tantalums, etc this way.

Very good point, thanks!
Funny thing I've seen this done several times but, for some reason, it didn't really cross my mind in this instance (let's blame it on tiredness  ;) ).
I will try that.
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #32 on: August 01, 2019, 07:28:38 am »
How much current am I supposed to run through this part of circuit?
I set my power supply to 1.5V and, initially, about 0.8A.
I then gradually increased current all the way up to 3A, but still no signs of heating on the board.
Heck, at 3A, the cable I soldered to one of the short points started to heat up, yet, I could not detect any hot areas/components on the board.
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #33 on: August 01, 2019, 09:17:55 am »
So, I bit the bullet and did what I have been considering for a while (but wanted to exhaust all other options before that): I've reflowed the NXP chip (i.e. U26).
This is because the seller of this meter mentioned they had dropped it, thus ending up with a broken screen.
So, I thought the impact may also have affected the connection between U26 and the board.

I am happy to report that, following the reflow, I am seeing a positive evolution: the 5V rail is now coming up and, consequently, the 2.5 reference voltage is present too.
Moreover, on pressing the power button, the LED beneath it turns on for a while, then turns back off, with the meter still drawing some current - from the videos I watched on Youtube, this is the expected behaviour.
Also, if I press the power button once more, the meter turns off (very little current draw from the power supply it is connected to).

The other good news is that, with the rotary switch set to Resistance, if I measure the current between COM and V terminals, I see very exact current being generated.
Moreover, if I press the Range button repeatedly, the current changes to very specific values (e.g. 100uA, 1mA, etc.).
So, at least some part of the meter is alive now.

Now, the not-so-promising observations (all this is done on the blind, as I have no working LCD):
- if I switch to Continuity test mode and short COM and V terminals, there is no sound generated (and I checked outside of circuit that the buzzer is working).
- if I set the rotary switch to DCV, for instance, and insert a lead into the u/mA or A jacks, the meter should beep to warn me I got the lead in the wrong place - however, I'm not hearing any sound.
- (still not sure if this is really an issue or maybe a red herring) the shorts on caps C46, C55 and C92 are still present.
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #34 on: August 01, 2019, 12:24:08 pm »
It's ALIVE !!!

What I've done since my previous post was to test the IR connectivity (thankfully, I had the IR-USB cable for it).
And the connection worked:
- I issued the "ID" command and got the correct response back
- I started issuing some "QM" commands in various settings of the rotary switch and the meter displayed at least the correct function
- Suspecting the meter might have some custom configuration settings from the previous owner, I went ahead and issued a "RMP" to reset to factory defaults.
And, surprise-surprise, the meter beeped when I turned it off.  :-+
So, of course, I then tested the input jack detection and I got the alert when the lead was inserted in the wrong jack.
Also, continuity testing is working now as well.
- Finally, I tested DCV readings from my power supply and they are pretty much spot on.

So, thanks to everyone here, it seems I've now got myself a meter in a fairly decent state (except for the LCD, of course).  :-DMM
Thank you all for your help!

Now off to finding a replacement LCD for it...
 

Offline say

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #35 on: August 01, 2019, 02:31:42 pm »
Congratulations on excellent results.


 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #36 on: August 01, 2019, 07:39:19 pm »
Thank you, say!
I wish it gives a boost of hope to yourself and everyone here in a similar situation with their meter.
 

Online giosif

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Re: Fluke 289 does not turn on -> blinking green power button
« Reply #37 on: August 23, 2019, 11:14:22 pm »
Just a quick update on this: I can confirm that the shorts on caps C46, C55 and C92 are NOT indicative of a problem.
My resurrected 289 measures short across those caps, yet it works just fine.
Moreover, I've recently got my hands on another working 289 (this one is the newer revision, with the coin-cell battery instead of the supercap) and the shorts across these caps is also present.
 


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