Portable calibrator repair attempt and success (Accidental connection to 220V)

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Electrical Metrology | Measurement Tips & Products | Calibration standards > Electrical Standards & calibration accessories

Kiriakos GR:
Even in the best houses shit happens, I was using this TE 1048 for several hours when I was testing software performance of TsDMMViewer.

At that day I was more tired than the calibrator and by the thought that my test cables were connected at the multimeter, I did connect the cables to Mains 220V.
But these test cables was actually connected to TE 1048 process calibrator. :(
This thing has Max input protection up to 25V DC and internal circuity designed at handle a peak of no more than 50V DC.

Yes my loved TE 1048 were seriously injured and chances for repair / recovery these were looking very slim.
My first thought was that such over-voltage it did fried any Integrated Circuit in it (IC) plus who knows what else.

By opening up my 1048 for inspection and damage assessment, I did notice a few PCB tracks them be totally burned.
Additionally few passive components were burned too beyond identification, and the PCB around those parts were also painted black from the blast.

Then I did contact my friends at Time Electronics in UK, and my email were received by them, when 48 hours previously the entire UK got in lock-down due the Corona Virus.
Therefore my email (Help request about receiving an schematic) this find them at their homes.

Even so, I am very thankful because they did find the way ( Thank you Brian !!) so I to receive help from one of their engineers who was having some files at his home computer.
And I did receive half schematic as assistance to parts recognition.

After making my own home work by inspecting this PCB (centimeter per centimeter) and its one component (all of them), I did succeed replacing anything burned by quality parts from my own stock.

And I did also restore point to point connection of any damaged PCB tracks and last stage this were careful entire PCB traces cleaning and removal of any blast marks residue.

Slowly and carefully and by every repair task this be made with precision and professionalism, in the fourth day the TE 1048 this shown first indication of LIFE :)
At the fifth day (today), I did managed to restore entire of it functionality!! 8)

At the time of the accident the 1048 this were at DC Volt & Source mode, and therefore the internal volt meter this using ICL7129ACPL, this also received 220V at it measuring input and this is now half dead (half sorted).
By removing the (half sorted) ICL7129ACPL all support signals and reference voltages at the IC socket they were restored!! (according to ICL7129ACPL schematic requirements).

Now I am in need for a new ICL7129ACPL which no one has in stock in Greece, but I did find a source in China (eBay).
This is an adventure that I will remember for my entire life time. :)

Now I am in need for a spare part when entire planet this is at temporally lock down or almost. ;D

Either way the smile this returned back to my face and I am in celebrating mode !! TE 1048 process calibrator this is alive and kicking, and factory calibration this is undamaged!
Now I am at hunting mode for the acquisition of a Not Fake MAXIM chip (to be continued.....)

Kiriakos GR:
This is a quick update. :)

About 26 days ago I did order all necessary spare parts for my calibrator 100% as NEW restoration.
At Corona virus times, cargo transport this is moving but much slower than before.

After a long waiting for a month time, my spare parts from China they did appear at Belgium, I am assuming now of another two weeks of added delay.
I am also waiting for a precision resistor, I found stock in Italy and placed my order two weeks ago.

Kiriakos GR:
We are getting back on the game! :)

Our new stock arrived:
2x ICL7129ACPL
10x IRF610
4x 12R 2W ±1% 50ppm/°C ROYALOHM MF02S

Newer 12R will replace a 12R which was a poor choice at product assembly line, the old one was just half watt and it shown to overheat and getting discolored.

Kiriakos GR:
Quick Update..

My Joy were taken away :( by the discovery that both received IC they were half damaged and or the second were a FAKE printed one.

I were refunded but this incident added 50 days of delay in this project all ready.
Now I am getting ready to re-order from another seller.