[Volt-nut] "HULK" Fluke 5720 calibrator rig build out of random broken boards.

[MadTux]

https://en.wikipedia.org/wiki/Swage_nut
And a bored person with a lathe

[2N3055]

https://eu.shop.bossard.com/group/en/9504/nuts-inserts/insert-nuts/bn-201_hex-self-clinching-nuts
You put it on the other side (like Fluke did) and you tighten it...

[TiN]

Those all are not the ones used. There is no thread on original insert but a lip for bolts head. Shield does not hold a bolt, it goes thru , just hiding the bolt head under surface.

[Kleinstein]

Does Fluke still sell the shield as a spare part ?  This might be easier than to get one made.

For the bolts, one might get away with just sink holes and mating screws. Not as pretty, but should be easier to get.

[TiN]

They did not even reply any of my parts quote requests before, so those were dead end wishes. Service manual implies that you can order parts, but you likely need to be NMI or big known cal lab for them to even spend time replying?

I could just bolt the shield using regular flathead screws, and it can work just fine. It  is just an idea to make it look kinda like real deal that bothers me . After all this time and funds inversted into this , skipping on little screws feeling like a betrayal .

[DC1MC]

Hi TiN, IMHO you want a set of these guys:
https://apexfasteners.com/fasteners/images/Flush-MountedPanelScrewComponents.pdf

It's true, they have thread on the insert, to retain the screw, but they are so designed that the screw head is flush with the insert, and the threads can be easyly drilled out.

 Cheers,
 DC1MC

[e61_phil]

but you likely need to be NMI or big known cal lab for them to even spend time replying?

My experience with Fluke Calibration is quite good. I had a few questions related to the uncertainties and their calculations of the recently bought 8508A and they answered in a very long detailed email and the contact person also created an excel sheet for me to play with the numbers. I also asked something about the specifications of the 5450A and the 5440B and they answered immediately.
Nevertheless, I bought a new 8508A a couple of weeks before and I asked with my company email.

[TiN]

They'd better answer questions that 22K$ DMM customer asks. However I didn't buy any 5700/5720A calibrators from Fluke, so my parts quote requests not justified I guess. .

Attached better pics of the nut.

[SteveP]

Hi,

How about https://www.mcmaster.com/#94350a130/=1dq264u

[TiN]

I think this is closest we can get, so I'll go with that.

Since outer covers aren't quite fixable, I also made few CADs for those. Like a bought one, eh?
Let's see how hard would it be to get these manufactured in one off qty.

[Zucca]

Solid Works?

[TiN]

They are solid

Little update today.

Took apart frame parts. Inguard frame is easily fixable, but outguard right wall need some work.



Even plastic guide frames are nearly intact, which is good news. I don't want all those boards floating inside willy nilly.



Also chopped off posts area from old ruined front panel plastic. Compare 57XX post construction vs 5500A one with shrouded banana receptacles  .



I'll trim excess plastic on sides, and make it fit just like glove on my 5500A front panel frame. Should all fit seamlessly.

[TiN]

Today's update, work on posts a bit to get the panel fit.

Condition before:



Condition after on my Fluke 5500A frame.



I had to file 0.3mm for key on the rods to make them fit the original Fluke base. Other the cap plastic color, rest of the LowThermal connector is identical.



USD $175 worth of connectors. Done.

[TERRA Operative]

Wow, that panel looked like junk but whatever juice you use in your magic wand turned it into practically a new item. Impressive work.

BTW, super jealous of your stuff, I want it all!


I'm gonna have to make friends with the local test equipment outlet/reseller here in Akihabara to see what gems I can score from their junk pile..

[Zucca]

Midas touch

[TiN]

After few days of bang-bang smash-smash, I got main chassis parts somewhat straight. Today decided to do a test fit and start assembly of the frame.
Here are few shots from today's timelapse footage. 



The cage didn't suffer much damage, and its geometry is acceptable. A3 and A4 motherboards align well.



Couldn't resist, and plugged all (almost) my inguard PCBAs inside to make sure all slides nice. No issue here, yay



Now time for heavy mains transformer frame and cooling fans. You can see transformer repaired wiring (previous owner chopped wiring right off ).



Now test fit with front panel assembly.



Outguard PSU and CPU cards install nicely too.



Like some said - there is distant light in the end of this XXXXX$ USD tunnel .

[branadic]

Congratulation to an almost finished investment. At the end, how much money did you safe compared to a fully functional but used unit?

-branadic-

[TiN]

I paid more than few recent sold ones on eBay, but I also get extra goodies too and few multiple boards to tinker with. It is also not one big payment but spendings over two years since I started collecting bits&pieces. If you want a unit, go buy used one, obviously. I knew from the start that it would be even or more $ than used box.

Anyhow, it's a learning process and fun that matters for me, and I'm happy to be able to do it. If you factor in cost of time , then most of "good deals" of broken T&M are more expensive than complete working units, but we still do it, right?

[Dr. Frank]

I paid more than few recent sold ones on eBay, but I also get extra goodies too and few multiple boards to tinker with. It is also not one big payment but spendings over two years since I started collecting bits&pieces. If you want a unit, go buy used one, obviously. I knew from the start that it would be even or more $ than used box.

Anyhow, it's a learning process and fun that matters for me, and I'm happy to be able to do it. If you factor in cost of time , then most of "good deals" of broken T&M are more expensive than complete working units, but we still do it, right?

Illya,
yep, the end of the tunnel comes closer..congratulations, and again - well done.

In the old days, it was quite easy to get old and damaged equipment for a bargain, with an easy fix.
Even from the US, including tax and VAT, it was possible to get top notch test equipment for a very low price.

Today, it's not that easy any more, up to impossible, maybe also due to the revival of DIY electronics and metrology instruments, by the eevblog effect..

Anyhow, I really appreciate very much all your re-engineering work you've done and that you're still doing.. and probably spending all your income on that stuff..
It's fun for you, for sure, but also a big knowledge benefit for everyone in this community.

And a big fun for me, also, to follow your progress.

At last, I just want to point to your unique final conclusions and categorization of the 3458As minor and major faults (U180!) .. that has helped a lot many people..

Ok, I think that's enough of ultimative adulation .. get this thing running, finally!

Frank

[dl1640]

old A18 can go bad easily due to CC resistors in PA supply section

just my experience, if A18 is too dusty it would cause output tripped if set value above 20V, and we get errors from A14~A16.

[TiN]

Initial chassis works done, so I decided it's time to test fit stuff and give it a smoke test.











There is still some bang-bang smash-smash work need to be done on the rear right corner, to get sh`t align properly, but I don't have patience to deal with that now.

So minimal set of boards installed, to allow me repair and do some checks on inguard A18 regulator board (yes, one that got carbonized by carbon resistor and have drilled holes now  ).

After few hours of jumpwiring and checking, I've got it working. No smoke and blown parts so far, yay!

Positive PA+ 375VDC output: 



Negative PA- -190VDC output. 



Tomorrow last piece arrives, so I'll continue to check regulator rails and voltages, and once all is good, will fit all boards in and see if the Hulk chuch. 

[ManateeMafia]

TiN,

Great job so far. I know you can't wait to run its first calibration. 

[TiN]

Received my bad A8 today (good A8 I had before had to go as part of chassis trade  ) .

Hybrid ceramic assembly looks good, rest I can repair easily. 

So excited, my hands are shaking! (better not when probing 565 volts on A18!) 

[dl1640]

saw the light.

such an epic.

[TiN]

  Yes, all boards are in (except 30MHz WB option, that is next step).



Sorry for ugly photo, just a quick shot, as I went to bed after 4am tonight. This thing sucking my life out.
Who can sleep anyway when there is 5720A in the room? 

And after few days of mangling with random non-documented diagnostics errors and swapping my spare cards, I finally have Hulk running.
Finished ACAL last (this) night, and now it is running thru paces with HP3458B.

Next step is to fix my wideband option board set (it trips output to standby in 12kHz-1.2MHz range, but works fine in 1.2MHz-30MHz range), and wait for some parts to arrive, like metal covers and random bits.



Then I'll have it fully assembled and be on 30-day calibration interval versus my 10K/10V/1ohm/4920M standards, to check if there are any hidden rabbit holes awaiting.