Fluke 5440A repair

[Rax]

Hi all,
I've been weirdly unable to find a datasheet for this DC Calibrator. Does anyone have one? All of the manuals I have are missing that "attachment."

Also, would appreciate some thoughts on it. What's the level of this really? Up to par for 6.5, or maybe 7.5 digit meters calibration?

It's a huge and heavy box for just DCV, for a while I thought I must be imagining things and it must include more functionality than just that.

[Swainster]

Do you mean the schematic? The datasheet should be easy to find. That said, I don't recall that the schematic was hard to find either...

Anyway, the 5440B is indeed a large heavy box, just for DCV... and it does it really well. To my mind, it's the best DCV reference that you can get in the kilobuck price range, and i seem to recall that it's in the 7.5 digit class. I mainly use it to transfer DCV from my in-cal 7.5 digit meter to 6.5 digits and below.

The down side is that you will still need a rack full of other instruments to give you ACV, current, resistance etc.

[alm]

It's a huge and heavy box for just DCV, for a while I thought I must be imagining things and it must include more functionality than just that.

The 5440 series is the most linear and stable DCV calibrator next to the Datron 4000/4708/4808 or Fluke 5700/5720 series. The latter can contain more functionality in the box (in the case of Datron depending on options), but certainly aren't any much smaller or lighter. The 5440 has the advantage over the Datron calibrators that the 11V range and higher ranges can be calibrated using artifact calibration using a single external 10V standard. Something the 5700/5720 can also do, but not many other calibrators (none of the Datron units). I have a paper 5440A manual but unfortunately it's also missing the specifications section. So it's not just scanned manuals that are missing it...

Apparently the 5440A is described in the 1985 (and probably 1984 and possibly 1983) catalogs, so if you could find a (digital) copy of one of these catalogs, they would probably give you some abbreviated specifications. You could message Bill158 to see if they still have access and would be able to scan those pages. Please share them if you find them.

I would expect them to be very close to the 5440B/5442A. It should be sufficient to calibrate 7.5 digit meters, and should be good enough for 8.5 digit meters in the presence of other standards (e.g. a more stable 10V DC standard).

[Rax]

The datasheet should be easy to find.

I have the component-level SM from Fluke (which is pretty spectacular face-value, but not unusual for the time), but no trace of the specifications anywhere. At least where I looked.

[Rax]

Converting this thread into a repair thread.

I essentially have a unit here which upon receipt had completely nonsensical display annunciations (8000000 on the left and a bunch of squares and a "?" on the right) and no output at LO/HI. Given these drastic symptoms I suspected power supply issues, and I did find that TP7 to TP8 and TP9 were completely off. Other voltages on the Inside and Outside Guard Regulators (A10 and A17) seem to be reasonably close (didn't try any adjustments at this point).

Replacing C17 through C20 resolved this issue (including CR21 turning off). Definitely not out of the woods yet, I still have roughly the same weird stuff displayed (and, BTW, one red LED is lit on A1, Keyboard Assembly), and no output from the unit.

I do see diagnostic LEDs lighting on different boards (just like CR21 was lit before fixing A10, and as I mention just above). I can't find anything on the SM on these... Can anyone point me to where this stuff is, please?

Any repair path forward recommendations are welcome. Thank you!

[bdunham7]

These guys say their manual has specs, I'd just ask them if they really have them and ask for your money back if they aren't in there.

https://www.ebay.com/itm/370513925603

Repair is probably going to be a challenge.  But that's what you're after, right?

Here's an advertising blurb.  I'd say these have a good enough TUR for any 6.5-digit meter and probably with guardbanding good enough for 7.5-digit.

[Swainster]

Apologies to Rax, I missed that he was looking for info on the 'A' version.

Looking forward to the repair - I have a 'B and the only issue that I've had so far is a couple of blown PCB fuses, which depowered the in-guard processor. Never found any reason for the blown fuse and its been fine since being replaced, so may have been due to aging.

These guys say their manual has specs, I'd just ask them if they really have them and ask for your money back if they aren't in there.

https://www.ebay.com/itm/370513925603

Satisfied Artek customer here (I've bought 2 or 3 manuals from them so far). I have found that Dave at Artek has always been really friendly and helpful, and their manuals to be their own scans. Should be no problem asking them for more info before purchasing.

[Andreas]

Hello,

the specs can be found here:
https://www.amplifier.cd/Test_Equipment/other/Fluke5442A.html

with best regards

Andreas

[Dr. Frank]

Hello,
it's not useful to ask about 6.5, 7.5 or 8.5 digit DMM calibration.
You only need to compare the possible uncertainty of the 544x A/B vs. the uncertainty of your intended DMM.
In principle, as the 10V output of the calibrator is extremely stable over time, much better than specified, and maybe better than usual 10V standards, it's also possible to calibrate DCV of a 3458A.

I append the specification table from a Fluke / Philips catalogue.

I have the 5440B_AF operation and service manuals, and both contain the specifications, of course. There are only small differences between 5440A / B, and 5442A as well. These might be available at xdevs.com.

Frank

[alm]

These guys say their manual has specs, I'd just ask them if they really have them and ask for your money back if they aren't in there.

https://www.ebay.com/itm/370513925603

Satisfied Artek customer here (I've bought 2 or 3 manuals from them so far). I have found that Dave at Artek has always been really friendly and helpful, and their manuals to be their own scans. Should be no problem asking them for more info before purchasing.

I 100% agree with the positive comments, but note that Dave has passed away recently, and while his wife is taking over the business, expect slower service. Also, I have that manual, and while section 1 is in the table of contents, the section is empty. Just like in my paper copy. I guess the leaflet was easily lost.

[MegaVolt]

Does anyone have one? All of the manuals I have are missing that "attachment."

You can use the documentation from the 5440B. The schemes coincide completely except for the control scheme of the front display.

[Rax]

the only issue that I've had so far is a couple of blown PCB fuses

This is a very good point, I need to evaluate all PCB fuses.

Satisfied Artek customer here (I've bought 2 or 3 manuals from them so far). I have found that Dave at Artek has always been really friendly and helpful, and their manuals to be their own scans. Should be no problem asking them for more info before purchasing.

Unfortunately, Dave has recently passed. Manuals are still available and the business is still attended to, but with some delays and a backlog. I think the eBay orders are being well catered for, but the ones through the website are not processed as well.

[Kosmic]

I 100% agree with the positive comments, but note that Dave has passed away recently, and while his wife is taking over the business, expect slower service. Also, I have that manual, and while section 1 is in the table of contents, the section is empty. Just like in my paper copy. I guess the leaflet was easily lost.

About Artek, I ordered a manual yesterday on ebay and it was shipped on the same day. So look like it's business as usual.

[Rax]

So look like it's business as usual.

See my post above, AFAIK only on eBay currently. I don't think the website is up yet. 

[Kosmic]

So look like it's business as usual.

See my post above, AFAIK only on eBay currently. I don't think the website is up yet.

I mean, for the ebay store. The web site is up but apparently (from the discussion on groups.io) they can't process orders from there. Probably better to avoid the website for the time being.

[Rax]

The web site is up but apparently

You're misreading what I meant by the "site being up."

[Rax]

Further work on this.

• pulled most boards and cleaned their header contacts with pure IPA
• also, checked their fuses
• ...and replaced a couple of electrolytics where I think they placed 85C ones far too close to toasty heatsinks... If the PCB is dark, that cap can't be doing well. Put 105C ones instead and tilted them a bit for heat clearance

No smoking gun yet. Again, if anyone has any information on the PCB LEDs error codes, I'd appreciate some direction. I can't find those anywhere. There are flickering LEDs on some of the boards.

[Rax]

Here are the fault codes I am getting from the LEDs on the boards:

• A16, Controller: CPU blinks very rarely; MEM, INT blink about 2x more often; FPC is continuously lit
• on the keyboard assembly, the FAULT LED is also continuously on

It looks like I am on the 2-13 2-41 pages on the SM, which I'm still "close reading..."

[Swainster]

Regarding the fuses which I changed, I recall that they looked just like an axial leaded resistor i.e. not a cartridge type. I dont think your issue is related to a fuse though, as they caused a whole section to go dead.

So far, my personal experience with old Flukes is that tantalum beads are often the culprit. That anecdotal evidence is based on a very limited sample size - I have hopes of increasing that sample size, however my lottery numbers have yet to come up.

[MegaVolt]

Again, if anyone has any information on the PCB LEDs error codes, I'd appreciate some direction. I can't find those anywhere. There are flickering LEDs on some of the boards.

[MegaVolt]

I gave initial setup tips in the topic:

https://www.eevblog.com/forum/metrology/another-fluke-5440baf-repair/

You can remove most of the boards and start by setting up the digital part.

[Rax]

I gave initial setup tips in the topic:

https://www.eevblog.com/forum/metrology/another-fluke-5440baf-repair/

You can remove most of the boards and start by setting up the digital part.

Thank you for this. I read your saga, but I'm not sure how much of it is applicable here. I think you had a bad IC on A16 (or A14? It's not clear which, and neither is which IC was bad). Also, you had a PS issue - which I also had (the +-30V rails), but fixed. I've also checked all fuses in sight and nothing seems open. Like I mentioned, I started selectively replacing stressed electrolytics, but may just go ahead and replace all dipped tantalums I see (probably with Nichicon HEs, unless anyone tells me they're not the right pick for the job in some of those tantalums duty).

On the logic/digital side of things, I am a bit raw. Different put, I am not sure how to read comms and bits and such. It sounds to me like you're suggesting taking all boards out (probably except all the supply boards) and see how that changes the codes?

If yes, given the codes (they seem pretty much exactly like yours in your thread), which would be your sequencing of swapping out and in?

[MegaVolt]

It sounds to me like you're suggesting taking all boards out (probably except all the supply boards) and see how that changes the codes?

List of removed boards.
https://www.eevblog.com/forum/metrology/another-fluke-5440baf-repair/msg3722311/#msg3722311

[Rax]

List of removed boards.
https://www.eevblog.com/forum/metrology/another-fluke-5440baf-repair/msg3722311/#msg3722311

Oh! One more thread to read!... Didn't realize there's that one also. Thank you.

I think you're saying - remove all boards from inside the guard cage and also A14 and watch for just the comms error with A14 to pop up? If yes, what error code would this be? Please have in mind I see nothing legible displayed on the right panel, and the left displays 800000H or something like this, where the last # changes occasionally depending on what I do to the unit (for instance, clean the edge connector on a board, etc.).

[MegaVolt]

Oh! One more thread to read!... Didn't realize there's that one also. Thank you.

)))))))

I think you're saying - remove all boards from inside the guard cage and also A14 and watch for just the comms error with A14 to pop up? If yes, what error code would this be? Please have in mind I see nothing legible displayed on the right panel, and the left displays 800000H or something like this, where the last # changes occasionally depending on what I do to the unit (for instance, clean the edge connector on a board, etc.).

This is problem ((

Then you have to watch the LEDs.

If you had a logic analyzer, you could stand on the display board and track the writing on the letter bus to the display.