Author Topic: [Volt-nut] "HULK" Fluke 5720 calibrator rig build out of random broken boards. (Read 41029 times)

TiN · « **Reply #125 on:** November 26, 2018, 11:22:10 am »

Xmas is early this year at xDevs.com labs...

Thanks to international support and USPS services, I am busy again, building something dangerous... Hulk deserves some more juice....

JohnG · « **Reply #126 on:** November 26, 2018, 01:53:26 pm »

syau · « **Reply #127 on:** November 26, 2018, 02:33:02 pm »

Transconductance Amplifier

TiN · « **Reply #128 on:** November 28, 2018, 04:30:44 am »

Yes, it is. I had thing shipped in bits and pieces with 3 boxes, due to international weight and shipping limitations. Don't ask how much that cost..

Pile of parts, eh?

PCBs set in a way how they are in the unit.

Key metrology component in the 5725A booster is High voltage sense assembly:

I was lucky to get one of later versions of this module in the unit, perhaps replaced during service sometime around year 2002 in the life of the box, as rest of the boards are dated 1993. This board have Fluke Thermal Sensor chip for AC/DC transfers, just like AC function boards in 57xx/792A and 5790A. Attenuator for 1100V AC and DC range is custom Fluke hermetic resistor network hiding under PCB block on top middle section.

How is all together in one piece again, so Digikey parts ordered to proceed with further repairs/troubleshooting as required. All electrolytic (except four huge 50000uF 20V caps, don't have those in stock) and tantalum capacitors, all carbon composition resistors will be replaced without questioning first, as preventive measure.

Quick power on check didn't cause any fires or smokes, and Hulk happily reported fan problem and locked down all controls. Good start I guess.
In case you wonder what's wrong with the fan:

Echo88 · « **Reply #129 on:** November 28, 2018, 10:56:47 am »

Is that a mini-version of the Guildline MightyMux-scanner on the ip-cam?

TiN · « **Reply #130 on:** November 28, 2018, 10:57:45 am »

No, it is not.

picburner · « **Reply #131 on:** November 28, 2018, 02:38:44 pm »

1529-R Chub-E4 Thermometer Readout......

SilverSolder · « **Reply #132 on:** November 28, 2018, 04:43:14 pm »

The fan looks like a low air restriction model!

TiN · « **Reply #133 on:** December 05, 2018, 07:30:28 pm »

Bob's your uncle!

Repair concluded that....there was no repair needed...

My intuition didn't fail me this time too, and building DIY interconnect cable between Hulk and Booster was a right move.

It may not look much, but I did my best educated guess, provide guaded low-noise Keithley PTFE coax for analog signals, low triboelectric noise Gore coax for calibration signals, guaded PTFE twinax for current lines (MFC can move all current ranges to booster output terminals, not just boosted 11A range) and multiwire digital shielded cable for data/comms/isolated power.

Now my little homelab capability extended to 11ADC/11AAC 10kHz and 1100VAC 30kHz/750VAC 100kHz.
Time to cook some DUT's

P.S. another progress is that I managed not to kill myself working on this. These boxes are very well capable of lethal shocks, with high-power 500V present on heatsinks and exposed connectors! Time to go for some sleep, 3:30 am here..

CalMachine · « **Reply #134 on:** December 06, 2018, 03:50:58 am »

Quote from: TiN on December 05, 2018, 07:30:28 pm

Bob's your uncle!

Repair concluded that....there was no repair needed...
My intuition didn't fail me this time too, and building DIY interconnect cable between Hulk and Booster was a right move.

That bright green power cable is remarkable

TiN · « **Reply #135 on:** December 06, 2018, 04:31:04 am »

Calibration check of 5725A before ACAL:

Code: [Select]

+    ------------------------------------------------------------------------
+                   ARTIFACT CALIBRATION DATES AND TEMPERATURES
+    ------------------------------------------------------------------------
+    Specification Interval:     24hour        Confidence:     99%`
+
+    MAIN OUTPUT:   (Most recent)  10/19/18,  22.6 Degrees C
+                      (Previous)  10/17/18,  24.0 Degrees C
+           (Days since last cal)  48
+
+    ZERO:          (Most recent)  12/06/18
+           (Days since last cal)  0
+
+    5725:          (Most recent)   5/03/16,  23.0 Degrees C
+                      (Previous)   4/28/16,  23.0 Degrees C
+           (Days since last cal)  946

It was last calibrated in 2016, some 946 days ago.

Code: [Select]

    ------------------------------------------------------------------------
                        5725 AC VOLTAGE OUTPUT SHIFTS
    ------------------------------------------------------------------------
    RANGE        Point            Full Scale Shift            Spec   Shift  
                                                              (+/-) (% spec)

      5725      FS              0.004  V     3.19   ppm    78.64 ppm    4.06
     1100V  1.0000  kHz         0.007  V     6.63   ppm    78.64 ppm    8.44
     1100V   5.000  kHz         0.003  V     2.67   ppm   110.45 ppm    2.42
     1100V  10.000  kHz         0.003  V     2.47   ppm   110.45 ppm    2.23
     1100V   12.00  kHz         0.001  V     0.54   ppm   110.45 ppm    0.48
     1100V   15.00  kHz         0.005  V     4.39   ppm   110.45 ppm    3.98
     1100V   17.00  kHz         0.005  V     4.21   ppm   110.45 ppm    3.81
     1100V   20.00  kHz         0.022  V    19.86   ppm   110.45 ppm   17.98
     1100V   30.00  kHz         0.036  V    32.43   ppm   240.00 ppm   13.51
      750V   30.01  kHz         0.011  V    14.80   ppm   244.67 ppm    6.05
      750V   40.00  kHz         0.032  V    42.14   ppm   244.67 ppm   17.22
      750V   50.00  kHz         0.027  V    35.63   ppm   244.67 ppm   14.56
      750V   60.00  kHz         0.030  V    39.44   ppm   660.00 ppm    5.98
      750V   70.00  kHz         0.049  V    65.86   ppm   660.00 ppm    9.98
      750V   80.00  kHz         0.065  V    86.42   ppm   660.00 ppm   13.09
      750V   90.00  kHz         0.100  V   133.59   ppm   660.00 ppm   20.24
      750V  100.00  kHz         0.133  V   177.48   ppm   660.00 ppm   26.89

    ------------------------------------------------------------------------
                        5725 DC CURRENT OUTPUT SHIFTS
    ------------------------------------------------------------------------
    RANGE Point     Zero Shift       Full Scale Shift          Spec   Shift  
                                                              (+/-) (% spec)

      5725 +FS     0.00003  A    -0.00055  A -50.26   ppm 372.73 ppm  -13.48
                -FS     0.00003  A     0.00061  A  55.25   ppm 372.73 ppm   14.82

    ------------------------------------------------------------------------
                        5725 AC CURRENT OUTPUT SHIFTS
    ------------------------------------------------------------------------
    RANGE        Point            Full Scale Shift            Spec   Shift  
                                                              (+/-) (% spec)

      5725  1.0000  kHz       -0.0005  A   -46.97   ppm   385.45 ppm  -12.19

Worst deviation is 27% of the spec at 750V 100kHz versus 24 hour spec? I'll take that as a win.

TiN · « **Reply #136 on:** April 19, 2019, 05:52:37 pm »

Call me nuts, but I think the M6 earthquake that happened yesterday noon (April 18, 2019) killed resistor in my 5720A.

I have no other reasonable explanation to this. Nobody touched the unit, it was just sitting, happily running tests since full assembly and calibration 68 days ago.
This network have 10,90,900,19,171,1710 ohms and provide main resistance and current output functionality of the calibrator, among two other hermetical film Fluke resistors next to it.
Enough to say, there is no off-the-shelf replacement for this part

Dr. Frank · « **Reply #137 on:** April 19, 2019, 06:09:58 pm »

That looks awful, you have my deepest sympathy.
Probably the array had been soldered under some tension, which now unloaded due to the strong vibrations.

Hope, that you find replacement part.

Frank

TiN · « **Reply #138 on:** April 19, 2019, 06:16:50 pm »

Funny enough, I have actually 10 of these networks in my ovenized resistance standard Fluke SL935 prototype.
Their 10 ohm elements are all connected in parallel form 1 ohm.

But I'm not going to vandalize calibrated standard for the resistor. $:-\$

maginnovision · « **Reply #139 on:** April 19, 2019, 06:26:42 pm »

Well hopefully you can find another, that really is a shame after all the work you've put into it.

SilverSolder · « **Reply #140 on:** April 19, 2019, 08:47:02 pm »

Good thing the earthquake didn't break bigger things, like your house!

ramon · « **Reply #141 on:** April 20, 2019, 02:27:39 am »

Sorry to hear that. It could be also your recent lab rearrangment. (or maybe both: earthquake and lab rearrangment).

I was only at first floor of some mall when the earthquake happened. Just on first floor I knew it was strong, so much more at higher floors like your place. Some earthquakes make building to swing (horizontally), other earthquakes make building to shake both horizontally and vertically (those are really scary and could make stuff jump). I felt one of those with jumps 4 years ago, and I was only at a 4th floor. If calibrator had another device stacked then the effect is much worse.

While there are some 'seismic rack' manufacturers in taiwan, I don't think it will be easy to buy, nor cheap. I have found Ikea 'Metod' kitchen cabinets to fit my needs. The metod cabinets also have pull out shelves, so it is easy to take device out and work on rear side of device.

But of course, I don't have a heavyweight Hulk monster at home, so don't know it will be helpful to you at all.

Tony_G · « **Reply #142 on:** April 20, 2019, 02:22:18 pm »

Can you buy it as a spare part from Fluke? I live down the road from them so i'm happy to swing up to Everett, pick it up and post to you if needed.

TonyG

TiN · « **Reply #143 on:** April 20, 2019, 05:52:34 pm »

Quote

Can you buy it as a spare part from Fluke?

I can't even buy innocent parts like plastic handle for 57xxA from Fluke, they are not willing to even reply with a quote a DIY enthusiast like me. Leave alone parts for component-level repair, even though this resistor network is also used unchanged on modern 5730A. But thank you for support

ramon
Rearrangement happen postmortem, after I discovered calibrator is dead and needed access to guts, so remove all parts. Before quake everything was working perfectly fine, it passed my weekly calibration check on all ranges/functions just that day morning.

e61_phil · « **Reply #144 on:** April 20, 2019, 06:47:38 pm »

Did you try to contact the local partner? In germany they work togehter with CalPlus GmbH and many of my contacts to Fluke Calibration are going through CalPlus.

TiN · « **Reply #145 on:** April 20, 2019, 06:49:32 pm »

I did a livestream on A3 board troubleshooting on Hulk-2 project. Beware, 4+ hours long of boring stuff.

https://youtu.be/LTO8yIvzz9M

branadic · « **Reply #146 on:** April 21, 2019, 07:30:20 pm »

Does the broken resistor belong to A11 module? If so, there is one A11 module on ebay.

-branadic-

TiN · « **Reply #147 on:** April 23, 2019, 04:54:55 am »

No, it's ohms assembly, A10. Replacement board on it's way.

Meanwhile I'm fixing A4 PCB for second calibrator project.
Board have internal short on layer 3 and layer 4 (6 layer PCB) between 900VAC and 44VAC winding circuits due to PCB burndown.

Had to carve a well to get access and cut conductive FR4 charr out.

Should I create new thread about this 5700 "B" build or keep posting in this one?

maginnovision · « **Reply #148 on:** April 23, 2019, 06:41:05 am »

Keep it here. When someone comes back years from now they don't have to search for part two.

TiN · « **Reply #149 on:** April 24, 2019, 04:26:27 am »

Okay, we can reference first unit as H1 and second as H2 then.

Some work on A4, restoring layer 3 and layer 4 damages.

Mains switch wiring after cutting out charred board patch:

And cave work in two spots where traces and charred PCB were milled out out:

Once done will fill all with epoxy and solder copper foil on top to restore shielding.


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Author Topic: [Volt-nut] "HULK" Fluke 5720 calibrator rig build out of random broken boards. (Read 41029 times)

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