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Electronics => Repair => Topic started by: TiN on August 20, 2018, 04:39:23 am

Title: Fluke 8846A repair shenanigans.
Post by: TiN on August 20, 2018, 04:39:23 am
Yes, another repair thread about benchtop precision DMM. This time it's not so precise, as usual stuff I mangle with, but more typical and commonly used Fluke 8846 6.5-digiter.  :popcorn:
This is possible, thanks to John for his donation in the name of science (and making another article).

(https://xdevs.com/doc/Fluke/8846A/img/meters_1.jpg)

I almost feel like it's Fluke invasion in the lab recently. It went from zero Fluke DMMs (87V is not accounted for) to three in no time.  :-DMM

Rear side already show some damage to us, by broken tab of the power entry block. No biggie, just 26$ part.

(https://xdevs.com/doc/Fluke/8846A/img/rear_1.jpg)

However when I try to power on thing, it just locks up in booting logo and nothing happens.

(https://xdevs.com/doc/Fluke/8846A/img/error_1.jpg)

Let's see who's inside? Good old LM399H, Fluke resistor networks, ALTERA Cyclone 1 FPGA's and bunch of other goodness.

(https://xdevs.com/doc/Fluke/8846A/img/in_like_flynn_1.jpg)

Transformer is rusty special, that's for sure. Nothing obviously broken. According to date codes on chips, it's made early 2006.
So I mangled with it for few hours, replaced all electrolytic caps (usual rule when doing any older than 10yr equipment repairs), applied freeze spray on Cyclone FPGAs and stuff around in testing for cold joints, and poof, thing suddenly came to life..  ::)

(https://xdevs.com/doc/Fluke/8846A/img/poweron_1.jpg)

Too easy repair, I thought! I turned it off, on, off, on, seem to be working fine.

Okay, let's have it meet the Hulk (that's nickname for my zombie calibrator).
Connected, turned on for 10 minute warmup, hooked cable, and...

(https://xdevs.com/doc/Fluke/8846A/img/test1_1.jpg) (https://xdevs.com/doc/Fluke/8846A/img/test4_1.jpg)

-3.8ppm on 10V, -3ppm on 1V, no worries.

(https://xdevs.com/doc/Fluke/8846A/img/test5_1.jpg) (https://xdevs.com/doc/Fluke/8846A/img/test6_1.jpg)

-6.6ppm on 100V, spot on at 1000V, woohoo.

(https://xdevs.com/doc/Fluke/8846A/img/testr3_1.jpg) (https://xdevs.com/doc/Fluke/8846A/img/testr2_1.jpg)

Resistance checks, +10.4 ppm on 10kohm 4W, -47 ppm on 10 ohm. Not too shabby.

(https://xdevs.com/doc/Fluke/8846A/img/testacv10_1.jpg) (https://xdevs.com/doc/Fluke/8846A/img/testdci_1.jpg)

ACV and DCI also working okay.
Almost spot on, lol, with zero warming up time. Too good to be true, right?  :-//

LAN port however does not work, cannot connect to it either in static IP mode, or DHCP. DHCP does not get any IP address from network. Perhaps LAN Phy is killed?
Whatever, connected GPIB, that worked. So I setup simple python script to datalog 10VDC and went to bed (it was 5:30 am already).

(https://xdevs.com/doc/Fluke/8846A/img/f8846_10v.png)

And sure enough, 10 minutes after I closed my eyes, poor meter died.  :-BROKE  :palm:
It hangs on same power on initializing screen.

BTW, Firmware on it is really old 1.0x, does anybody have newer 2.xx firmwares for 8846A? Fluke removed it from website for no good reason  :palm: :rant:

Any ideas what to pursue next?  >:D
Title: Re: Fluke 8846A repair shenanigans.
Post by: coromonadalix on August 20, 2018, 10:35:51 am
Ask Fluke first for any FW updates, and on a previous thread someone had some boot up issues, check eevblog threads (maybe you have seen it ?)

Fluke must had a good reason to remove it loll    to keep some curious eyes away loll  or complicated updates procedures, i don't know, you loose nothing to ask.

Retry a more region precise  freez spray to replicate your findings, as you say it can be any "cold joint soldering" and maybe an Flir camera to check thermal problems ?
Title: Re: Fluke 8846A repair shenanigans.
Post by: Zucca on August 20, 2018, 02:17:48 pm
... the Hulk (that's nickname for my zombie calibrator).

You don't know I searched few days ago in google the "Hulk calibrator" nothing, "Fluke Hulk" nothing... and I gave up.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Mario87 on August 23, 2018, 08:29:35 am
....applied freeze spray on Cyclone FPGAs and stuff around in testing for cold joints, and poof, thing suddenly came to life.

So just to clarify, you didn't reflow or rework the solder joints? Just used the freeze spray? If you just used the freeze spray to test for cold solder joints and it started working again, then suddenly stopped once left on for a while I would look at reworking the solder joints, as it sounds like the freeze spray was enough to make the joint contract and make contact, but when on for a while it expands and breaks the connection.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on August 24, 2018, 04:08:13 am
Correct, didn't reflow anything. I freezed FPGA (as my suspects for BGA ball contacts) - nothing happened. Then freezed one of the IR diodes, and it got to work those 30 minutes.
I have opto's and FPGA already in upcoming digikey order.
Title: Re: Fluke 8846A repair shenanigans.
Post by: dacman on August 28, 2018, 01:38:48 am
I searched for
   Fluke8846A-Firmware2.10.882.24.zip (which I think should also work for the 8845A)
and got a hit at
   https://doc.xdevs.com/doc/Fluke/8846A/fw/
but I get a forbidden error.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Mr.B on August 28, 2018, 01:57:07 am
(https://www.eevblog.com/forum/repair/fluke-8846a-repair-shenanigans/?action=dlattach;attach=508199;image)
Title: Re: Fluke 8846A repair shenanigans.
Post by: lowimpedance on August 28, 2018, 02:55:23 am
LOL  :D........

But on the "Forbidden" ...
I also ran into this error when looking to see what keithley 177 schematic quality was, (linked to it in another thread recently).
Couldn't see the xdevs one so I uploaded a decent copy to that 177 thread.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on August 28, 2018, 03:09:58 am
There is easier way (https://xdevs.com/fix/f8846a/#firmware)?  ;)
Repository tree migrated, so old URLs borked, sorry.

I have parts from Digikey ordered for meter repair, will see if my intuition is right end of the week.  :-DMM

(https://xdevs.com/doc/Fluke/8846A/img/f8846_ir.png)

IR shot reveals not much wrong :)
Title: Re: Fluke 8846A repair shenanigans.
Post by: coromonadalix on August 28, 2018, 10:21:18 am
What the part heating up at 78.43 degree, i find it very hot for an small part ?
Title: Re: Fluke 8846A repair shenanigans.
Post by: glarsson on August 28, 2018, 10:43:53 am
If I remember correctly it is the LM399.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on August 28, 2018, 10:52:37 am
Yep, that is ovenized LM399. It's internal constant temperature by design is about 95 °C.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on August 31, 2018, 03:14:32 pm
I have  a couple of questions about 8846A. I hope you dont find it irrelevant to this thread though

-most serial numbers for this unit start with 9xx like 923 962 etc...but there is a unit I am negotiating for and the serial number starts with 118
and I also have seen SN starting with 108. How do the firmwares match to these serial numbers?

-can this Noritake display work in this DMM http://noritake-vfd.com/gu256x64d-7000bx.aspx (http://noritake-vfd.com/gu256x64d-7000bx.aspx)

-finally, does this meter has the measurement auto HOLD feature that holds the measurement and shows the last few of them like the newer Keysight models? I cannot see a hold key on the front panel

EDIT: attached is the datsheet for that Noritake VFD

sorry if this seems out of scope for this thread but since TiN is here and most other DMM experts will visit this thread I am hoping someone could help
Title: Re: Fluke 8846A repair shenanigans.
Post by: coromonadalix on August 31, 2018, 06:08:44 pm

http://noritake-vfd.com/gu256x64d-7000bx.aspx (http://noritake-vfd.com/gu256x64d-7000bx.aspx)

 
Ohhhhhhhhhhhh  nice display    would be nice on a HP 34401   like the eevblog thread ...
https://www.eevblog.com/forum/repair/hp-34401a-dmm-with-leaking-segments/ (https://www.eevblog.com/forum/repair/hp-34401a-dmm-with-leaking-segments/)
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on August 31, 2018, 06:12:32 pm
even mouser has it.

although it does not have the BX suffix. I dont know what is the difference.

however, my question remains: does this fit 8846A?

https://www.mouser.ca/ProductDetail/Noritake/GU256X64D-7000?qs=sGAEpiMZZMvkC18yXH9iImO64zrkImZBrdAMGtROkPM%3d (https://www.mouser.ca/ProductDetail/Noritake/GU256X64D-7000?qs=sGAEpiMZZMvkC18yXH9iImO64zrkImZBrdAMGtROkPM%3d)
Title: Re: Fluke 8846A repair shenanigans.
Post by: Kleinstein on August 31, 2018, 09:56:43 pm
The display is a graphics type display with driver board  -so it at least the same class of display like in the 8846. So there is still a chance is might work, but I don't know.

It would definitely not fit the 34401 or the Keithley 200x meters, as these use 7 seg based displays.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Vgkid on August 31, 2018, 10:28:36 pm
@TiN
Where did your manual repository go . I really liked it.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on September 01, 2018, 04:34:47 am
Its all there, just update links due server config changes.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on September 05, 2018, 12:36:38 pm
I was still hoping someone could answer my earlier question:

does this meter (8846A) has the auto HOLD feature that holds the measurement and shows the last few of them like the newer Keysight models? I cannot see a hold key on the front panel
Title: Re: Fluke 8846A repair shenanigans.
Post by: Samogon on September 05, 2018, 04:27:34 pm
I was still hoping someone could answer my earlier question:

does this meter (8846A) has the auto HOLD feature that holds the measurement and shows the last few of them like the newer Keysight models? I cannot see a hold key on the front panel

As i understand they implemented "Histogram Function" which is more advanced, but not really hold function as we used to.
Title: Re: Fluke 8846A repair shenanigans.
Post by: dacman on September 05, 2018, 09:34:55 pm
It has a Memory key (next to F5).  If memory is turned on, the meter can store several thousand readings internally or optionally externally if it is an 8846A.  (The 8846A has a USB port that can be used to store readings.)  If you wanted to see the last few readings, it has a Last softkey that could be used then you could scroll backward.  It also has an Analyze key (which is separate from the Memory function) that can be used to turn on STATS.  Then things like average and standard deviation and high/low can be displayed and it can show a graph of the readings.  Histogram is a graph of the standard deviations.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on September 05, 2018, 10:05:32 pm
It has a Memory key (next to F5).  If memory is turned on, the meter can store several thousand readings internally or optionally externally if it is an 8846A.  (The 8846A has a USB port that can be used to store readings.)  If you wanted to see the last few readings, it has a Last softkey that could be used then you could scroll backward.  It also has an Analyze key (which is separate from the Memory function) that can be used to turn on STATS.  Then things like average and standard deviation and high/low can be displayed and it can show a graph of the readings.  Histogram is a graph of the standard deviations.

yes, I know  but that would also store all the readings between probings. With reading hold (or probe hold as keysight call it) it stops
capturing when you take your probe away and reads a new measurement when you touch the probe and only if the new value
is different than the last one by more than 1%. With simple memory it keeps reading and storing the noise when you are not probing.

I have looked all over the manuals and I am 100% convinced now that neither 8846A nor DMM6500 have this simple useful feature.
All keysight multimeters and most older Fluke have it and even rigol and siglent have this. It's a simple software thing and i dont know why they decided to do away with it
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on September 24, 2018, 04:29:42 pm
Just curious what it took to fix unit ? If you needed FPGA.

Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on September 24, 2018, 05:20:41 pm
It's still dead.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on September 24, 2018, 05:44:02 pm
 Bummer

Just asking cause I had chance to buy a couple of non-functioning units or a couple of functioning units.

After your answer I decided on functioning units.

I have to correct that... I bought a couple of units with errors which keep unit from functioning!
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 06, 2018, 05:26:05 pm
Hmm...
Seems like this could be a common problem. :-BROKE


Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 06, 2018, 06:40:45 pm
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)

Title: Re: Fluke 8846A repair shenanigans.
Post by: GreyWoolfe on October 06, 2018, 08:15:34 pm
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)

At least you didn't ask that question in the TEA thread!!
Title: Re: Fluke 8846A repair shenanigans.
Post by: DC1MC on October 06, 2018, 08:20:39 pm
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)

The cost of sending them to Fluke for service is acceptable, on the other side, the cost of the servicing, this is what kills you ;).

Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 06, 2018, 08:43:01 pm
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)

The cost of sending them to Fluke for service is acceptable, on the other side, the cost of the servicing, this is what kills you ;).

 :-DD

Yep. IME, it costs about as much, if not more, than a used one in good working order. The four I have appear to have the same fault, but one is a bit different in it's behavior... More tomorrow.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 06, 2018, 08:47:07 pm
Yea, why did I even ask  :palm:

I should know better! Waaaaayyyyy too expensive.

I have two units with same error but one has all power rails working properly and one has shorted -15 and +15.
So same error covers a lot of different issues.
Title: Re: Fluke 8846A repair shenanigans.
Post by: giosif on October 06, 2018, 09:01:17 pm
Anyone getting bored of one of these sick puppies, I'd be glad to alleviate the burden.  ;D
Title: Re: Fluke 8846A repair shenanigans.
Post by: coromonadalix on October 07, 2018, 03:01:10 am
Sad to see theses meters having problems and Fluke does'nt acknowledge a thing ???
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 07, 2018, 03:33:01 am
What would you want Fluke to do? :) I'm sure they will help you with repair for 90% of new unit cost  :-DMM

So far my experience with this 8846 just tend to consider it as overcomplicated design filled with unfriendly firmwares. BGA FPGAs with NIOS SoPC, no way to backup firmware, Fluke withdrawal of their own published FW and poor service documentation. Sure I'd accept that in meter like 8508A, but not in benchtop unit like 884X.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 07, 2018, 12:18:49 pm
Yea, why did I even ask  :palm:

I should know better! Waaaaayyyyy too expensive.

I have two units with same error but one has all power rails working properly and one has shorted -15 and +15.
So same error covers a lot of different issues.

You're probably right. I can see the self test routine:
1 to 199: Run a whole bunch of self tests.
200: If anything fails, sit there and look stupid.

So the four units I have were bought by a friend of mine who brings me lots of repair work from a Govt. auction. Normally, he doesn't buy test gear, but other industrial equipment (hardness testers, etc)
https://www.govdeals.com/index.cfm?fa=Main.Item&itemid=17539&acctid=2863 (https://www.govdeals.com/index.cfm?fa=Main.Item&itemid=17539&acctid=2863)

If he had asked me about them before buying, I would have told him to stay away!

Symptoms:

1. All hang at the init screen.
2. When there is a USB thumb drive plugged in, three of them access the drive at 2 seconds and 8 seconds after powering on. No further accesses are done after that. The fourth one accesses the drive at 2 seconds, then at 3 second intervals over and over forever.
3. All voltage rails are verified and correct.
4. None respond to a GPIB scanning
5.All connect to LAN, and activity pulses can be seen at two second intervals. One time I saw one of them connect to my Asus router and get an IP address. I was unable to get it to repeat this though...
6. I never see any data going across the opto-coupler transmitter at DS3. The other one is transmitting a steady stream of pulses. I'll have to check whether the receiver is getting them, but you got to pull the board or remove the cover to access it. @ TiN: Does this sound like yours?

EDIT: The data stream from DS2 is making it across fine. Whether the data is correct, though... :-//

Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 07, 2018, 12:43:55 pm
Yea, why did I even ask  :palm:

I should know better! Waaaaayyyyy too expensive.

I have two units with same error but one has all power rails working properly and one has shorted -15 and +15.
So same error covers a lot of different issues.

Shorted to GND? Do you have a 4 wire DMM?
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 07, 2018, 01:54:32 pm
The 15 V rail sits at 2.18V the -15 at 0.434V

Found a comparator, IC LM393, that is running over 200 degrees F, on the second unit only 87degrees.
Will be investigating that today.


Title: Re: Fluke 8846A repair shenanigans.
Post by: Shock on October 07, 2018, 03:03:26 pm
Tin these look under done, please bake yours more. :D

Might be something to look at I cannot see from the thermal image what temp the right hand one is at. Did you check them and are those tantalums between?

Did you freeze spray that area at all? You may have hit a cap.

(https://www.eevblog.com/forum/repair/fluke-8846a-repair-shenanigans/?action=dlattach;attach=541460;image)
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 07, 2018, 03:41:44 pm
Tin these look under done, please bake yours more. :D

Might be something to look at I cannot see from the thermal image what temp the right hand one is at. Did you check them and are those tantalums between?

Did you freeze spray that area at all? You may have hit a cap.


A better pic you can zoom in on:
https://xdevs.com/doc/Fluke/8846A/img/fixed_in.jpg (https://xdevs.com/doc/Fluke/8846A/img/fixed_in.jpg)
Title: Re: Fluke 8846A repair shenanigans.
Post by: HighVoltage on October 07, 2018, 04:37:47 pm
I used to have a 8846A because it was so much praised here on eevblog.

My unit was bought used with a very weak VFD, but I thought that would be an easy fix.
I tried forever to get a new VFD from Tektronix or other sources and I finally gave up and let go of the instrument.

Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 07, 2018, 11:48:52 pm
All power on my 8846 is fine, nothing cooking or shorted. It is not relevant to the "init screen hang" issue, because meter should boot even with inguard section completely unpowered (removed transformer cable from inguard).

Jwalling, yes, there is no life on optos from outguard to inguard. There is slow square wave on pair from inguard to outguard (perhaps just heartbeat signal).
I have tried so far things like:
* Replace RJ45 magnetics and Eth phy (suspected dead LAN input, that get NIOS CPU in FPGA stuck waiting) = no help.
* Replaced outguard SDRAM = no help
* Replaced outguard FPGA (bought new Cyclone from Digikey) = no help
* Freezespray bunch of stuff around  = no help anymore. Originally it helped and made meter work randomly for shortime.

When it was working, it took about 10-20 seconds to boot from init screen, and you can hear relay click after 2-3 sec from power on. Now it however does not click anything, just sitting silly.

Supervisor chip that drive reset to NIOS FPGA is ok, reset is correctly toggled high on power on. There is some life to SDRAM data pins, so it's doing something.
I tried to probe RS232 chip in hope to find debug CPU console output, but there was no signals.

So far best shot would be to trace JTAG to the debug connector, and connect USB Blaster, to try if anything can be done from that side (perhaps read back NOR flash).
But it's a long shot, as we don't have binary image from the FW flash. 8846A update tool have only bits and pieces, but not the full dump binary.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 08, 2018, 10:40:15 am
What would you want Fluke to do? :) I'm sure they will help you with repair for 90% of new unit cost  :-DMM

So far my experience with this 8846 just tend to consider it as overcomplicated design filled with unfriendly firmwares. BGA FPGAs with NIOS SoPC, no way to backup firmware, Fluke withdrawal of their own published FW and poor service documentation. Sure I'd accept that in meter like 8508A, but not in benchtop unit like 884X.

Re: Firmware for the Fluke version, have you tried contacting Erik?
https://www.eevblog.com/forum/testgear/fluke-8846a-anyone-that-got-the-updated-firmware-downloaded/msg1511872/#msg1511872 (https://www.eevblog.com/forum/testgear/fluke-8846a-anyone-that-got-the-updated-firmware-downloaded/msg1511872/#msg1511872)

https://www.eevblog.com/forum/testgear/fluke-8846a-anyone-that-got-the-updated-firmware-downloaded/msg395578/#msg395578 (https://www.eevblog.com/forum/testgear/fluke-8846a-anyone-that-got-the-updated-firmware-downloaded/msg395578/#msg395578)

Apparently, Fluke removed the update utility as too many people could not follow the instructions. Maybe they were bricking them?
assets.fluke.com/software/bench/readme.pdf (http://assets.fluke.com/software/bench/readme.pdf)
Title: Re: Fluke 8846A repair shenanigans.
Post by: Circlotron on October 08, 2018, 10:46:41 am
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)
You could always couch it in terms of how much money you would be saving ;-)
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 08, 2018, 11:21:38 am
Jwalling
You think where I got this one from? (https://xdevs.com/fix/f8846a/#firmware)
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 08, 2018, 11:39:24 am
Jwalling
You think where I got this one from? (https://xdevs.com/fix/f8846a/#firmware)

Oh. sorry. I thought you were looking for firmware...
Title: Re: Fluke 8846A repair shenanigans.
Post by: Jwalling on October 08, 2018, 11:51:36 am
Doing some more poking around.

Cost to repair from Tek is $895.

The three units I have that behave the same with a USB drive attached, were from the University of Central Florida. All three had an RMA generated, but they never sent them in. Probably when they found out the repair cost.  :-DD

The fourth belonged to Entest Inc.

My gut feeling is that the firmware is probably corrupted on these. But it's just a guess...
Oh for the days when firmware was in PLCC sockets.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 08, 2018, 01:06:19 pm
$895.00 Guess that answers my question !

About the price of a used 8846A DMM.

But it comes back calibrated also!
Title: Re: Fluke 8846A repair shenanigans.
Post by: coromonadalix on October 08, 2018, 03:24:23 pm
895$  Each dmm  or the loot ??
Title: Re: Fluke 8846A repair shenanigans.
Post by: Kleinstein on October 08, 2018, 04:16:23 pm
I think from the screen shots it should be clear that this is $895 per unit and excluding shipping and likely sales tax.  Given the rather high price some units might end up as display donors. The repair price is so high, because is in many cases this would be a board swap.

Firmware corruption could be possible, though I would expect a check sum test at the beginning and than a corresponding error message - just like TiN's 3458. Several units with a similar fault might make it worth to dig a little further.  As a broken communication should be caught by the ground based part, I would suspect trouble with the outbound part. Just in case one could do a test with an intentionally broken link - at least this should be caught, as it would be an expected failure mode (e.g. spider at the optical link).

Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 08, 2018, 10:33:10 pm
Kleinstein
Usual NIOS people not thinking the same way as Motorola designers of 3458 FW. Why need to include debug/fault info for user, if we can just demo pretty Fluke intro bitmap on that lovely VFD, and ask user to pay for service? :)

Friend of mine tried to block opto on working 8846 and meter still was able to boot into main UI, just don't show any readings. So if meter no boot = outguard issues.

Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 08, 2018, 11:00:38 pm
Tin, you changed Outguard FPGA correct?

Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 08, 2018, 11:24:20 pm
Yes.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 08, 2018, 11:55:00 pm
On my unit the Inguard is not responding.

I have a functioning Outguard.
But no readings on display...
Removing the shields from the phototransistors reveals  "XC6115 series  high-precision, low current consumption voltage detectors with watchdog. The series consist of a reference voltage source, delay circuit, comparator and output driver".
Which is what triggers my error after a few seconds delay. I can see the pattern on the oscilloscope.

Outguard waiting for a signal, then resetting after time delay, coinciding with the error message appearing on the display.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 09, 2018, 04:16:37 am
Johnny10, slow down, or you will get me wasting time on this 8846 again.  :-DD

On serious note - good find.  I think reversing schematics for isolation interface would be rather easy.
Title: Re: Fluke 8846A repair shenanigans.
Post by: picburner on October 09, 2018, 06:51:31 am
Quote
Removing the shields from the phototransistors reveals  "XC6115 series  high-precision, low current consumption voltage detectors with watchdog.

To me U54 & U63 look like AD8601ARTZ op-amp.
In fact a phototransistor pin is connected to the -in input of the op-amp and this makes sense.
What would it do to connect to the wd terminal of an XC6115??
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 09, 2018, 12:15:18 pm
I am certainly not an expert on SMD markings since I have been wrong before.

SMD part marked AAA 5 pins SOT-25.

I used  SMD-Codes from 2007

Title: Re: Fluke 8846A repair shenanigans.
Post by: picburner on October 09, 2018, 01:23:35 pm
The smd codes are difficult to interpret and often generate confusion because the same code can correspond to many different devices.
I don't have this DMM and then I can't make measurements but to amplify the signal of a phototransistor I would use a hi-speed op-amp not a
voltage detector with watchdog ;)
Title: Re: Fluke 8846A repair shenanigans.
Post by: Miti on October 17, 2018, 02:39:42 am
Hi Tin,

My 8845A had a dying IR LED but it popped an error, I don't remember which error. I replaced it with a regular IR LED from an old TV remote and it works well for about 2 years now. Spray cold those LEDs, replace them. It's worth a try.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on October 17, 2018, 04:37:24 am
Hi Tin,
My 8845A had a dying IR LED but it popped an error..

IR led was second thing I swapped (first one was check and confirmed good, also recap all power supply circuits). Didn't help.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on October 20, 2018, 11:14:03 pm
OK, More testing validates picburner

Pin 1 Signal Out
Pin 4 Input
Pin 5 V+  3.43V

on the AAA 5 pin IC  AD8601ARTZ
Title: Re: Fluke 8846A repair shenanigans.
Post by: massivephoton on October 31, 2018, 02:03:04 pm
LAN port however does not work, cannot connect to it either in static IP mode, or DHCP. DHCP does not get any IP address from network. Perhaps LAN Phy is killed?

Too bad ethernet didn't work even while the unit worked. Telnet on port 23 asks for login/psw, which is disclosed in plaintext in the available 2.x firmware files. Once inside, there's uCLinux basic commands, ftp server, some scripts for comm configuration as well as default settings stored.

Symptoms:
(...)
5.All connect to LAN, and activity pulses can be seen at two second intervals. One time I saw one of them connect to my Asus router and get an IP address. I was unable to get it to repeat this though...

Did you ever manage to get an IP again? You could try to login on port 23 and inspect. Also, there are chances that the firmware update (or downgrade?) tool works from this point.

My unit runs the latest firmware listed in Xdevs.com, and I'm having a minor issue that if I break the telnet connection sometimes it no longer accepts SCPI connections on port 3490, but keeps alive at port 23. I know I shoudn't be using wi-fi with instruments, but hey, it's pretty good when it works. Already tried to reboot each network devices in the path between the notebook and the DMM, but didn't work. I'd like to telnet connect on port 23 and restart the telnet process to regain SCPI control on port 3490, but when I kill the only telnetd process listed on `ps aux` command, the connection on port 23 is interrupted. I can reconnect on port 23, but  it doesn't restore telnet connection on port 3490. Also, if I run a reboot command, it restarts the outguard processor, the DMM keeps measuring and updating the display, but still no connection on telnet on port 3490.
I can try to replicate tests or copy files from the instrument if needed. You may try to convince me, but I just don't feel inclined to open the unit, since it's still under warranty. Sorry, I couldn't resist and turned it on instead of tearing it apart. :-(

Hope your meters return from the dead soon!
Happy halloween!
Title: Re: Fluke 8846A repair shenanigans.
Post by: SilverSolder on November 02, 2018, 02:03:18 am

(https://xdevs.com/doc/Fluke/8846A/img/meters_1.jpg)


What is the purpose of the aluminum box over the input connections on the 8508A in the picture?  In later pictures, it (or a clone) appears on the calibrator as well.
Title: Re: Fluke 8846A repair shenanigans.
Post by: massivephoton on November 06, 2018, 02:58:01 am
Had a little more time to play on the weekend.

All power on my 8846 is fine, nothing cooking or shorted. It is not relevant to the "init screen hang" issue, because meter should boot even with inguard section completely unpowered (removed transformer cable from inguard).

Probably, but I wouldn't be so sure on v1 firmware.

Quote
Jwalling, yes, there is no life on optos from outguard to inguard. There is slow square wave on pair from inguard to outguard (perhaps just heartbeat signal).

The measurement app is ca. 1MB in size, /usr/bin/zfp. Killing this process halts measurements, freezing the display. I'd expect the opto communication to halt too. Zfp app is called at the end of /etc/rc script:

Code: [Select]
#!/bin/sh
#
# system startup.

# expand and mount the ramdisk
#/bin/dd if=/usr/bin/ramfs.img of=/dev/ram0
/bin/expand /ramfs.img /dev/ram0
/bin/mount -t ext2 /dev/ram0 /tmp -n
/bin/expand /ramfs.img /dev/ram1
/bin/mount -t ext2 /dev/ram1 /var -n

# mount proc file system
/bin/mount -t proc proc /proc -n

# mount sysfs
/bin/mount -t sysfs sysfs /sys -n

# mount the jffs2 R/W file system
# /bin/mount -t jffs2 /dev/mtdblock2 /usr -n

# mount the romfs RO (SAFE) partition
/bin/mount -t romfs /dev/mtdblock4 /safe -n

# Configure the GPIB interface
/usr/bin/gpib_config

# manually assign ip address (uncomment and edit as appropriate)
# note: first ifattach (no args) sets local loopback
/bin/ifattach

# Set the MAC and IP address
/usr/bin/setmac
/usr/bin/ipenet

# start up the internet superserver
/bin/inetd &

# run 2 sec delay
/usr/bin/me_sleep

#If the application was installed using a windows
#machine the files may not be executable so change
#the permissions just-in-case
chmod 777 /usr/bin/zfp

#Start up the application
/bin/sh -c /usr/bin/zfp &

# that's it... success
exit 0

Quote
I have tried so far things like:
* Replace RJ45 magnetics and Eth phy (suspected dead LAN input, that get NIOS CPU in FPGA stuck waiting) = no help.

It's also possible that eth0 initialization script didn't complete. The firmware update manual mentions the ip 169.254.115.202. Also, setenet script on /usr/bin further mentions the following ip/mac tables:

Code: [Select]
mac_address='00:80:40:00:20:AE'
ip_address='129.196.136.131'

case $1 in
    halfdome) mac_address='00:80:40:00:20:A6' ; ip_address='129.196.136.112' ;;
    mlandich) mac_address='00:80:40:00:20:A7' ; ip_address='129.196.136.116' ;;
    dbartley) mac_address='00:80:40:00:20:A8' ; ip_address='129.196.136.117' ;;
    zippy)    mac_address='00:80:40:00:20:A9' ; ip_address='129.196.136.119' ;;
    rdz)      mac_address='00:80:40:00:20:AA' ; ip_address='129.196.136.122' ;;
    denny)    mac_address='00:80:40:00:20:AB' ; ip_address='129.196.136.125' ;;
    jwitters) mac_address='00:80:40:00:20:AC' ; ip_address='129.196.136.129' ;;
    britz)    mac_address='00:80:40:00:20:AD' ; ip_address='129.196.136.130' ;;
    test1)    mac_address='00:80:40:00:20:AE' ; ip_address='129.196.136.131' ;;
    test2)    mac_address='00:80:40:00:20:AF' ; ip_address='129.196.136.200' ;;
esac

Note how close the mac address found here:
00:80:40:00:56:A9 [on the screenshot]

On my unit the mac address starts with 00:C0:, which might suggest that something is wrong on eth0 initialization. I'd suggest to ping and/or telnet these ips using an auto mdi-x adapter or crossover cable configured with an ip on the same subnet.

Some services to play with:
Code: [Select]
ftp-data 20/tcp
ftp 21/tcp
telnet 23/tcp
uptime 24/tcp
http 80/tcp

I think uptime can be useful to an automation task know that the unit is already warm-up. Telnet connection return an increasing number, not sure, but maybe tens of minutes, and immediately closes connection.

Quote
* Replaced outguard SDRAM = no help
* Replaced outguard FPGA (bought new Cyclone from Digikey) = no help
* Freezespray bunch of stuff around  = no help anymore. Originally it helped and made meter work randomly for shortime.

Any chance that the flash memory got its last breath from a cold breeze?

Quote
When it was working, it took about 10-20 seconds to boot from init screen, and you can hear relay click after 2-3 sec from power on. Now it however does not click anything, just sitting silly.

When zfp app is launched it adjusts measurements, and the relays fill their mag lungs to cry hello world!

Quote
Supervisor chip that drive reset to NIOS FPGA is ok, reset is correctly toggled high on power on. There is some life to SDRAM data pins, so it's doing something.
I tried to probe RS232 chip in hope to find debug CPU console output, but there was no signals.

I didn't see any indicia of console on tty on the files. I didn't even connect using serial yet, but I'd try 115200 baud, at least on later firmwares, since inittab file on /etc shows:
Code: [Select]
# inittab for uClinux
# Format:
# ttyline:termcap-entry:getty-command
  ttyS0:vt100:/bin/agetty 115200 ttyS0

# ttyS1:vt100:/bin/agetty 9600 ttyS1
# ttyS2:vt100:/bin/agetty 9600 ttyS2

# ttyJ0:vt100:/bin/agetty 115200 ttyJ0

Hope there's something like uboot halt on any key here...

Quote
So far best shot would be to trace JTAG to the debug connector, and connect USB Blaster, to try if anything can be done from that side (perhaps read back NOR flash).

I agree, but only if ethernet really not initialized, and also if we don't find any boot console at tty.

Quote
But it's a long shot, as we don't have binary image from the FW flash. 8846A update tool have only bits and pieces, but not the full dump binary.

I must say that the firmware seems to include the full firmware, in pieces, it's true, but integer pieces. After extracting recursively the firmware, we get a folder 'instruments_e6f0b851bdee_zg_ia_sf/884X/bin' holding the firmwares, with the following files: beta_noinfo_reversed.rbf,
busybox, f884x_versions, flashcp, flash_eraseall, jffs2.bin, me_sleep, u69_nios.flash, vmlinux.bin, vmlinuxRev14ptf.bin, vmlinuxRev17ptf.bin, zfp, zfp_837;
and the recipes under /884X/procedures show exactly where each image should go.

One last bit, restarting zfp app restores my measurement telnet connection at port 3490.  :popcorn:

Regards.
Title: Re: Fluke 8846A repair shenanigans.
Post by: TiN on November 06, 2018, 03:07:14 am
Cudos for the investigations, that could be very helpful. Perhaps its possible to build "binary image" that can be flashed to new flash chip to try? My meter have 1.x few so there is no "source" update part for this version. But I'd love to try that and even buy programmer that can do TSSOP56 chips.
Title: Re: Fluke 8846A repair shenanigans.
Post by: massivephoton on November 06, 2018, 01:12:54 pm
Cudos for the investigations, that could be very helpful. Perhaps its possible to build "binary image" that can be flashed to new flash chip to try? My meter have 1.x few so there is no "source" update part for this version. But I'd love to try that and even buy programmer that can do TSSOP56 chips.

I think it's possible to build a binary. I'm not sure if mtdblock[0-4] really are partitions of the same flash chip. If so, we can find the offsets and create the image. Also, I can try to copy the entire 2.37 flash from my unit to a single file on a usb pendrive. Just don't know how to do it yet.

Also, the firmware 2.10.882.24 already includes full images to upgrade from 1.x:

Code: [Select]
09/29/06-16:59,null    [OG SW]
10/06/06-22:22,null    [IG SW]
09/26/06-15:16,null    [OG HW]
09/26/06-15:23,null    [IG HW]
Sep 27 2006,null       [OS Build]
r1,proc_649_130        [Rel. 1 --> Rel. 7: upgrade using proc_649_130]
04/02/07-08:10,null
10/06/06-22:22,null
09/26/06-15:16,null
09/26/06-15:23,null
Sep 27 2006,null
r2,proc_688_130        [Rel.2 --> Rel.7: upgrade using proc_649_130]
11/09/07-09:21,null
09/14/07-21:54,null
08/20/07-20:19,null
08/21/07-16:30,null
Aug 23 2007,null
r3,proc_837_200_082307 [Rel.3 --> Rel.7: upgrade using proc_649_130]
11/09/07-09:21,null
09/14/07-21:54,null
08/20/07-20:19,null
08/21/07-16:30,null
Oct 25 2007,null
r4,proc_837_200_102507 [Rel.4 --> Rel.7: upgrade using proc_649_130]
11/09/07-09:21,null
12/12/07-20:15,null
08/20/07-20:19,null
08/21/07-16:30,null
Nov 30 2007,null
r5,proc_837_201        [Rel.5 --> Rel.7: upgrade using proc_649_130]
11/09/07-09:21,null
02/15/08-18:44,null
08/20/07-20:19,null
08/21/07-16:30,null
Nov 30 2007,null
r6,proc_837_210        [Rel.6 --> Rel.7: upgrade using proc_649_130]
02/14/08-08:54,null
02/15/08-18:44,null
08/20/07-20:19,null
08/21/07-16:30,null
Nov 30 2007,null
r7,proc_882_210        [Rel.7 --> Rel.7: upgrade using proc_649_130]

For instance, the code for procedure proc_649_130 is:
Code: [Select]
connect,null
wiz,syst:rem
step,1
tcomm,rm /usr/bin/vmlinux.bin
tcomm,rm /usr/bin/u69_nios.flash
tcomm,rm /usr/bin/vmlinuxRev14ptf.bin
tcomm,rm /usr/bin/beta_noinfo_reversed.rbf
tcomm,rm /bin/busybox
fcwd,/usr/
fget,calparams
fcwd,/bin/
fput,busybox
fcwd,/usr/bin/
fput,vmlinuxRev14ptf.bin
fput,flashcp
fput,flash_eraseall
fput,zfp
fput,me_sleep
tcomm,chmod 777 /usr/bin/flashcp
tcomm,chmod 777 /usr/bin/flash_eraseall
tcomm,chmod 777 /usr/bin/me_sleep
tcomm,rm /usr/bin/config/*
tcomm,mv /usr/bin/vmlinuxRev14ptf.bin /usr/bin/vmlinux.bin
tcomm,/usr/bin/flashcp -v /usr/bin/vmlinux.bin /dev/mtd1
tcomm,rm /usr/bin/vmlinux.bin
disconnect,null
reboot_simple,null
connect,null
wiz,syst:rem
step,2
fcwd,/usr/bin/
fput,vmlinux.bin
tcomm,/usr/bin/flashcp -v /usr/bin/vmlinux.bin /dev/mtd2
tcomm,rm /usr/bin/vmlinux.bin
fput,beta_noinfo_reversed.rbf
tcomm,/usr/bin/flashcp -v /usr/bin/beta_noinfo_reversed.rbf /dev/mtd0
disconnect,null
reboot_simple,null
connect,null
wiz,syst:rem
step,3
tcomm,/usr/bin/flash_eraseall -j /dev/mtd3
tcomm,mkdir /mnt/jffs2_blk3
tcomm,chmod 777 /mnt/jffs2_blk3
tcomm,/bin/mount -t jffs2 /dev/mtdblock3 /mnt/jffs2_blk3 -n
tcomm,rm -Rf /mnt/jffs2_blk3/*
tcomm,dd if=/dev/mtd1 of=/mnt/jffs2_blk3/jffs2.bin
tcomm,flashcp -v /mnt/jffs2_blk3/jffs2.bin /dev/mtd1
disconnect,null
reboot_simple,null
connect,null
wiz,syst:rem
step,4
fcwd,/usr/bin/
fput,u69_nios.flash
restorecal,null
wiz,syst:rem
step,5
wiz,ig_download "/usr/bin/u69_nios.flash"
message,"UPDATE DONE"
disconnect,null
end,end

Procedure proc_882_210 does nothing, since the installed firmware is already release 7.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Nifty on April 22, 2021, 06:16:35 pm
So many brave (or naive) people
Title: Re: Fluke 8846A repair shenanigans.
Post by: Johnny10 on April 22, 2021, 06:40:09 pm
You can buy a working used one on ebay for 550 dollars.  Oops, I take that back, all 12 are sold.

Tektronix DMM4050 6.5 Digit Multimeter
Item Information
Condition:
Used
Quantity:
0 available 12 sold / See feedback
Price:
US $550.00
$47 for 12 months with PayPal Credit
opens a installment calculator layer
*
Title: Re: Fluke 8846A repair shenanigans.
Post by: BU508A on December 13, 2021, 07:50:43 pm
I've found the datasheets for the two display versions:

Noritake Itron VFD Module, 256x64 Dot Graphic

Type 1: GU256x64D-7000
Type 2: GU256x64D-7000BX

Differences I've found so far:

- BX is newer (2016 vs. 2006)
- block diagram
- BX has a higher power consumption / higher current consumption
- to be continued ...


TME has five tpye 1 displays ready for delivery:
https://www.tme.eu/de/details/gu256x64d-7000/vfd-displays/noritake-itron/ (https://www.tme.eu/de/details/gu256x64d-7000/vfd-displays/noritake-itron/)
Title: Re: Fluke 8846A repair shenanigans.
Post by: dew on March 04, 2022, 04:44:40 am
I'm new to this, but AFAIK:
Fluke is using it's own controller for VFD display in 884XA meters. VFD part is MN25664J. It is an older model with 5V supply and logic.
Same VFDs are used in GU256X64D-3900 or GU256X64D-3900B displays
Noritake (manufacturer?) (https://noritake-vfd.com/gu256x64d-3900b.aspx)
Mouser (https://www.mouser.com/c/?q=GU256X64D-3900)
DigiKey (3900) (https://www.digikey.com/en/products/detail/noritake-company-inc/GU256X64D-3900/559551), DigiKey (3900B) (https://www.digikey.com/en/products/detail/noritake-company-inc/GU256X64D-3900B/4879261)
These GU[...] displays come mounted on their own controller with UART interface that you would not need for the Fluke. Very hard to take VFD off the controller. Glued with double side tape across the whole surface.

GU256X64D-7000_tme and GU256X64D-7000BX_tme both seem to use MN25664M VFD module (glass part). M version is newer, uses 3.3V and a different interface.
Title: Re: Fluke 8846A repair shenanigans.
Post by: ASEMechanic on January 21, 2023, 04:51:23 am
I'm new to this, but AFAIK:

Fluke is using it's own controller for VFD display in 884XA meters. VFD part is MN25664J. It is an older model with 5V supply and logic.

Same VFDs are used in GU256X64D-3900 or GU256X64D-3900B displays

...

These GU256X64 displays come mounted on their own controller with UART interface that you would not need for the Fluke. Very hard to take VFD off the controller. Glued with double side tape across the whole surface.

Okay, I'm going to revisit this very old thread because it actually helped me out this week. And this will be a long post, so grab your popcorn. :popcorn:

I bought a Fluke 8846A off eBay fairly cheap because it had an aging display with pretty bad burn-in. Still perfectly functional and recently calibrated, so I thought I'd give it a shot. Unit arrived, plugged it in, and fired it up. As expected, the display was a bit dim and the burn-in was noticeable, but otherwise it was perfectly functional. Certainly not disappointed as I knew what I was getting.

Aaaaaaand then I began the process of trying to locate a replacement display. Going through normal channels yielded zip. No Fluke replacement parts anywhere. Well, it's an older discontinued device so I get it. Started scouring forums and came across the XDevs thread regarding a Fluke 8846A teardown. https://xdevs.com/fix/f8846a/ (https://xdevs.com/fix/f8846a/) (This is, incidentally, the exact same article and unit found at the start of this very thread posted by TiN, although I hadn't seen this thread yet.) Anyway, it thankfully indicated the part number of the VFD and gave me something else to work with.

2 days of scrounging, parts sourcing, and even looking for dead units to salvage a display from again yielded nothing. I was about to just give up and resign myself to a dim display, at least until I could procure a reasonable working one later on down the road, when I came across this very thread. The post above gave me hope, although I had to be realistic that it was from almost 5 years ago and that I may not be able to find anything available.

Leave it to Mouser... They actually have 58 (now 57 ;)) of the GU256X64D-3900B displays in stock. Yes, they're pricey at $270.48, but they absolutely do have the MN25664J VFD display on them. The same display that is in the 884xA meters. I ordered one and hoped for the best. In the meantime, I went ahead and opened the unit up to remove the display and controller from the front panel. I wasn't going to touch it until I could verify that I could remove the new display from the controller, but at least it was just that much less to do when it arrived.

Got my display in today (Friday) at about 11:00 AM. Verified that the pinout all looked correct and then went to work. First thing was to separate the adhesive. This was actually easier than I had anticipated. I'm not sure about the display Dew had observed, but this one had 2 thinner strips of double sided tape on the edges instead of one wide sheet. A little Goof-Off and a thin razor knife made quick work of separating the controller board from the VFD, leaving only the terminals. 21 terminals to be exact. Using a couple small pieces of PCB for leverage between the VFD and controller board, I applied a little pressure and used the hot air from my solder rework station to slowly draw the terminals out. This took about 5 minutes as I didn't want to force anything and possibly break a pin or crack the glass of the VFD.

Once I got it all apart, I verified that the part number was identical (it was a match!), and then I then went to work on taking the old display off of the Fluke adapter board. This was considerably easier as I just cut the old one off and removed the terminal pieces one at a time. A little solder wick, a quick wash, and the board was ready to go. I inserted the new VFD into the adapter, spot soldered the end terminals, and then I placed the assembly into the meter panel so that I could get the offset correct with no gaps. With the adapter board screwed back in place, I finished soldering up the terminals. After a quick check to make sure everything looked good, I then reassembled the meter.

Fired the unit up and it worked like a champ! Display is crisp and clear. I ran the display test and that completed perfectly. This whole process went about as well as could have been expected (or hoped) and only took about 2 hours from start to finish.

If anyone is in need of a VFD for the Fluke 884xA, I can tell you that this is about the only option available. If you have a solder rework station and have no qualms about sacrificing the GU256X64 controller, then this is a sure way to get a new display. It works well and it isn't nearly as difficult to accomplish as it appears.

Mouser still has these:
https://www.mouser.com/ProductDetail/Noritake/GU256X64D-3900B (https://www.mouser.com/ProductDetail/Noritake/GU256X64D-3900B)

Noritake also still lists these on their website:
https://noritake-vfd.com/gu256x64d-3900b.aspx (https://noritake-vfd.com/gu256x64d-3900b.aspx)

I hope this post helps someone the same way that the previous post helped me.

Good luck!!

The Noritake GU256X64D-3900B display disassembled (http://thecohrons.com/billcohron/images/GU256X64D-3900B.jpg)

The Fluke 8846A display and adapter board (http://thecohrons.com/billcohron/images/Fluke_8846A_VFD_and_Adapter.jpg)

The Fluke 8846A with new VFD installed (http://thecohrons.com/billcohron/images/Fluke_8846A_New_VFD.jpg)

Title: Re: Fluke 8846A repair shenanigans.
Post by: bdunham7 on January 21, 2023, 05:03:40 am
Well, it's an older discontinued device so I get it.

Good work!  Just to be clear, was the display assembly (p/n 2454039) unavailable from Fluke directly or was it just too expensive?  The meter is discontinued, but just recently and I would expect it to still be supported.
Title: Re: Fluke 8846A repair shenanigans.
Post by: ASEMechanic on January 21, 2023, 05:59:11 am
I did find that part in the manual, but there was nothing I could find anywhere on the internet pertaining to the front panel P/N 2454039. Even the VFD part MN25664J itself was severely limited in information. None of the Fluke parts or repair facilities I contacted had anything available.

I think the problem is that while Noritake still manufactures the MN25664J VFD, they no longer sell it individually. This severely limits availability of the part. The only way you can get them is attached to one of their controllers. I do have an e-mail into Noritake VFD to see if there's any way to be able to acquire the VFD individually. We'll see where that goes.

At least for now, there is a workable solution. My meter has a brandy-new display and I'm a happy camper.  :-+
Title: Re: Fluke 8846A repair shenanigans.
Post by: gamalot on January 21, 2023, 01:14:51 pm
Tonight is Chinese New Year's Eve, I gave myself a gift, upgraded my Tektronix DMM4040 to Fluke 8846.

Just about half an hour ago, I happened to see this topic, and then saw that someone had uploaded firmware to xDevs.com, so I decided to try my luck.

Now I am very happy, as you can see in the pictures it can correctly measure capacitance and temperature, those are not features of DMM4040 nor 8845.

Thank you so much everyone!  >:D
Title: Re: Fluke 8846A repair shenanigans.
Post by: ASEMechanic on January 21, 2023, 03:37:05 pm
Wow! That's pretty cool. I didn't even realize that you could upgrade the meter by just changing the firmware. I guess it makes sense, though. All the hardware is there, just need the right software.

Yeah, I downloaded everything xDevs had on their site for the Fluke 884x meters. From the address where you downloaded the firmware, just enter the directory address without the filename. The directories allow indexing so you can see everything in there. Then it's just Right-Click and Save As. You won't be disappointed!

Since 8845s go for less than the 8846 (some as low as $700), I may try to pick some up and upgrade the firmware in them. :-+

Good luck and enjoy your new meter.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on January 21, 2023, 03:44:41 pm
dmm4040 does have the USB while Fluke 8845A does not so in that regard dmm4040 is closer to 8846A/dmm4050

If I am not mistaken the boards on 8845A and 8846A are not identical. Well, they are but there are a couple of missing chips on 8845A
which might be the USB controller. I might be totally wrong...

I have not seen the inside of DMM40xx....
Title: Re: Fluke 8846A repair shenanigans.
Post by: ASEMechanic on January 21, 2023, 03:59:19 pm
dmm4040 does have the USB while Fluke 8845A does not so in that regard dmm4040 is closer to 8846A/dmm4050

If I am not mistaken the boards on 8845A and 8846A are not identical. Well, they are but there are a couple of missing chips on 8845A
which might be the USB controller. I might be totally wrong...

I have not seen the inside of DMM40xx....

Gotcha. Well, it was a thought anyway.

As it turns out, Noritake Elec. *WILL* sell just the MN25664J display directly through them. 8-12 week lead time and ships directly from Japan. Price? $153.00 for 1-9 units and $135.20 for 10+ units.

Anyone with weak displays interested in a group buy??  ;)
Title: Re: Fluke 8846A repair shenanigans.
Post by: alligatorblues on January 22, 2023, 07:17:48 am
What does it cost to send them to Fluke for service?

Or is that a question not allowed in the repair forum. :-)

If you send a 884xA in for calibration (~200$), Fluke will make any small repairs necessary at no charge. Last one I sent in they reflowed the solder joints on front terminals, and updated to latest firmware, both at no charge. But you must have Fluke put on the quote to update firmware, or it might not get done, as was the case with a different meter I sent in for cal.. I had to send it back to get the firmware.

Fluke does not give out firmware, because if you buy the front cover, keypad, and what not, you can make a 8846A from a 8845A. They are nearly identical, except for the cosmetics and firmware. If you complain about no free firmware, Fluke will just tell you to shove it, like, "We're Fluke. We don't have to care. We have no competition."

They've even done some minor repairs on 732Bs when I sent them in for cal..
Title: Re: Fluke 8846A repair shenanigans.
Post by: gamalot on January 22, 2023, 08:14:49 am
dmm4040 does have the USB while Fluke 8845A does not so in that regard dmm4040 is closer to 8846A/dmm4050

If I am not mistaken the boards on 8845A and 8846A are not identical. Well, they are but there are a couple of missing chips on 8845A
which might be the USB controller. I might be totally wrong...

I have not seen the inside of DMM40xx....

The difference between DMM4040 and 8846A I can see from the outside is the color of the case, front bumper, handle, and the printing on the front panel (including the glass window and buttons).

I opened the case to see what's different inside (clear the dust by the way), and I saw an 8846A mainboard inside my DMM4040.

I uploaded some pictures here, you can also find high-res pictures of the board on github https://github.com/gamalot/DMM4040-Pictures (https://github.com/gamalot/DMM4040-Pictures) .
Title: Re: Fluke 8846A repair shenanigans.
Post by: Kleinstein on January 22, 2023, 08:20:22 am
They have tighter specs for the 8846 compared to the 8845. So there can also be  differences in the quality of parts (e.g. better selected resistors or reference) and maybe testing of the whole PCB (those that did not so well in the tests get used for 8845). From the outside a new LM399 looks the same as one with a 3 month burn in and tested for noise.
Title: Re: Fluke 8846A repair shenanigans.
Post by: gamalot on January 22, 2023, 08:59:52 am
They have tighter specs for the 8846 compared to the 8845. So there can also be  differences in the quality of parts (e.g. better selected resistors or reference) and maybe testing of the whole PCB (those that did not so well in the tests get used for 8845). From the outside a new LM399 looks the same as one with a 3 month burn in and tested for noise.

I'm sure they'd save the money if they could.

---

You can see that J10 and J13 are populated in the picture of Illya's 8846A, but not in my DMM4040.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on February 21, 2023, 10:26:14 pm
Tonight is Chinese New Year's Eve, I gave myself a gift, upgraded my Tektronix DMM4040 to Fluke 8846.

Just about half an hour ago, I happened to see this topic, and then saw that someone had uploaded firmware to xDevs.com, so I decided to try my luck.

Now I am very happy, as you can see in the pictures it can correctly measure capacitance and temperature, those are not features of DMM4040 nor 8845.

Thank you so much everyone!  >:D

i am still wondering how this could have worked? FW for 8845A and 8846A are the same, also the FW for 4040 and 4050 were the same so I think there must be something on the board or in the flash that identifies the model number and it should not be erasable and modifiable by a FW upgrade...

So did the fluke FW complately erased the flash including whatever identified the unit as dmm4040 and replaced it with 8846A?

Do you see FLUKE logo at startup now?
Title: Re: Fluke 8846A repair shenanigans.
Post by: gamalot on February 22, 2023, 08:44:33 am
I think all the information is overwritten during the firmware update, except the calibration data.
Title: Re: Fluke 8846A repair shenanigans.
Post by: analogRF on February 22, 2023, 11:32:41 am
I think all the information is overwritten during the firmware update, except the calibration data.
do you know what was the OutG FW version of the unit originally? was it below 2.10?

and one last question, are the Cap and Temp measurements in spec? They should not be I guess...
Title: Re: Fluke 8846A repair shenanigans.
Post by: gamalot on February 22, 2023, 04:07:47 pm
I don't remember the exact original version number, but I'm sure the original DMM4040 firmware had a higher version number than the 8846A I flashed into it.

As for the capacitance and temperature test functions, of course they have not been properly calibrated, and some default values should be used. I found some capacitors and tested them. I can see that comparing the 34465A and the LCR meter, the results of the DMM4040 have very large errors in certain ranges. I didn't do temperature measurements because I don't have the right equipment.
Title: Re: Fluke 8846A repair shenanigans.
Post by: Miti on February 23, 2023, 07:09:11 pm
I can see in the xDevs hi res pictures, there are two SOIC8 ST devices with labels on top. I assume they are configuration devices for the FPGAs. Has anyone tried to dump those and compare a good one with a bad one? Is it possible that something is corrupt there?
Title: Re: Fluke 8846A repair shenanigans.
Post by: charlyd on August 31, 2023, 11:04:58 am
Hi is there any progression on the bootup...initializing...... error?