Electronics > Repair
Fluke 5440B repair
Rax:
--- Quote from: Tony_G on July 25, 2024, 08:13:15 pm ---Random question Rax, did you replace/check the relays? One of my 5440s Fluke rejected for cal due to relays and I've never got around to addressing.
Just wondering,
TonyG
--- End quote ---
Tony,
Not really, no. I've just ran some of the corresponding diagnostics and I think my next step will be to swap modules to localize the issue (as I have this other 5440A that works correctly).
On checking the relays as its own thing, I am not entirely sure how I'd ago about that, need to think about it and figure it out. It's a good recommendation though.
Tony_G:
I wouldn't have bothered getting the unit calibrated but I live down the road a bit from Fluke so I could drive the unit to their location rather than shipping it - I'm not sure how they determined that the relays were an issue (metrology, volt-nut noob...) but I haven't tried some of the suggestions of cleaning the relays.
Interested to see what you discover.
TonyG
leighcorrigall:
--- Quote from: Rax on July 25, 2024, 06:35:35 pm ---The other things I'd like to see as a 3D print file is the spacers used inside these 5440s (see pic). I'll dig up the part number and real name, but anyone having opened one of these has stumbled upon these little knoblets. They become very brittle with time, and I have not run into the situation where I'd pull them with "no victims" in a new unit having landed at my desk.
I'll give a shot to making some 3D files for this and see what comes out.
--- End quote ---
If you keep the parts, they can be glued back together with epoxy and care. Once dry, you can use a razor blade to clean off the excess. I think I have a CAD file for them somewhere, as I was also concerned about them breaking. Unfortunately, I have no time to print them right now, but if you remind me after August 12th, I can see if I can fabricate them with a high-quality printer. You have my email.
I think I also saw a talk about calibrating this unit. I highly recommend that you do not calibrate a unit until you have had plenty of experience with it (> 6 months of operation and use). If there is a subtle fault, you may be wasting your money. Believe me, I made the mistake of being hasty a while ago with an Advantest R6581T.
Rax:
--- Quote from: Rax on July 25, 2024, 06:35:35 pm ---The other things I'd like to see as a 3D print file is the spacers used inside these 5440s (see pic).
--- End quote ---
I think these are Fluke 421776 ("DORCAS?..."). So I made this in Fusion.
Rax:
This afternoon I finally got the earthmover (...) to carve out some room at the bench, enough to have two of these behemoths open side by side. Not sure I'll be able to get the car we usually garage inside the garage tonight...
So, I was able to swap modules from the known good unit to the issue unit such that I'd isolate the issue. And this far tests are a bit confusing. Per SM (p.4-14), given the error message, A8, A9, and A4 are prime candidates for issues. A4 and A8 A9 seem to change nothing, essentially, so I'm deeming them good. Swapping A9 A8 doesn't fix the issue, but instead returns a different error. Actually, errorS! Initially, there was something about, I think, "inside guard" (it was one time and I didn't write it down immediately), and now I'm consistently getting "OUTPUT LIMIT FAULT. OUTPUT OVER VOLTAGE." But, this was upon me asking it to output 10V, and I didn't see it outputting more, so that's a bit weird. It seems there's some false flag errors triggering or something.
I'll dig down deeper, but if anyone sees any sense in the above, I'm all ears. All I can conclude this far is that the issue may have to do with A9, though a known good module didn't fix it. For anyone asking, the module in both units is a "5440A" module, so I don't suspect any updates to the "B" unit modules make the swapped "A" unit unfit.
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