Author Topic: Metrix MX4940 (Metrel) electrical installation tester  (Read 969 times)

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Offline shakalnokturn

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Metrix MX4940 (Metrel) electrical installation tester
« on: September 25, 2018, 11:07:10 pm »
I recently picked up this tester sold as "without leads therefore untested" for a reasonable price, obviously I don't believe that it wasn't tested.
Anyway the price/functionality ratio looked good enough to give it a go, besides I quite like all the Metrix equipment of that era that I've used.

Upon first tests the U.I. is pretty basic and will take some time to get used to, (obviously absolutely no documentation to be found throughout the WWW), only low Ohm measurement seems to work correctly, other tests will not run as the meter shows a false voltage reading of about 80V and will not allow tests to run on a live circuit.

Leaving the meter powered long enough voltage reading drops low enough for the insulation test to run, test voltages are well below normal on all ranges, resistance measurement is off by a few MOhms for a test resistance of 10MOhm (DMM input).

On opening the meter, battery compartment has some remains of leakage, main PCB has small signs of corrosion, so with a little luck I may get away with a good wash.

The odd thing is that the main PCB is marked "Metrel", so nothing to do with Metrix... Unless Metrix maybe designed the front panel PCB.

So just in case there is more information available with Metrel, I'd be curious to know if anyone can tell me of a Metrel model that is mostly equivalent to the Metrix branded meter I have?

Offline coromonadalix

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Re: Metrix MX4940 (Metrel) electrical installation tester
« Reply #1 on: September 26, 2018, 03:36:55 am »
Surely an good pcb clean up may or would help ...   maybe trying to write down all the trimpots values before playing with them ???
Metrel was established in 1957 as a factory for the production of electrical measuring instruments and components for the domestic market and grew from there to become one of world’s leading manufacturers of measuring and testing equipment.

Metrix is now known as Chauvin Arnoux, some Beckman industrial meters where Metrix based  ....  you can ask them a few questions, you could have some answers ???
« Last Edit: September 26, 2018, 03:42:36 am by coromonadalix »

Offline shakalnokturn

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Re: Metrix MX4940 (Metrel) electrical installation tester
« Reply #2 on: January 25, 2019, 01:23:43 pm »
Dumped the firmware EPROM today, examining contents it seems to support 4 or 5 similar meters, one of which is the HT Italia Macrotest HT2033, there are a couple of pictures of it on the www.
The firmware also reveals that it seems to have multilanguage support for the RS232 data export, I wonder if there was specific software for this and where it can be found today. Will have to get in touch with Metrel / Chauvin Arnoux some time once it has been repaired.

Offline sorenkir

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Re: Metrix MX4940 (Metrel) electrical installation tester
« Reply #3 on: January 25, 2019, 02:54:13 pm »
I have a 9100 EXPERT from Francaise d'Instrumentation which is also made by Metrel.
It also sold by Beha (UNITEST 9020) and the user manual is online :
Maybe it can help to understand how to use it,as it seems to have comparable features...
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Offline shakalnokturn

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Re: Metrix MX4940 (Metrel) electrical installation tester
« Reply #4 on: March 24, 2019, 01:09:25 am »
Thanks sorenkir for the tip, that actually will be of some help.

I finally got this tester fixed. Started replacing the IC's that had the most corrosion (a couple of TL064 and a TL062) no better, still the slow decaying electrolyte contamination symptoms. I could't improve this by scrubbing patches with a toothbrush and IPA.

In the end I removed the laminated core transformer (earth resistance test) to prevent it from rusting and took all but the display assembly for a nice hot shower, white vinegar and scrub, followed by washing-up liquid scrub and a good rinse and 2 days drying in the sun.

Then it took me a couple more hours to find my mistakes: One small transformer wire broken by the scrubbing, and one of the earth resistance test transformer's pins I forgot to re-solder in the rush getting it back together.

Anyway, it now all seems to work and in reasonable enough calibration form me to not want to attempt any better.

Now I'm looking for any of the RS-232 data collection software that may be suitable for this, be it from Chauvin/Metrix, Beha, F.I., HT Italia, or maybe the older Metrel "installtest" software if anyone out there has a copy of that I'd be greatfull.

Offline shakalnokturn

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Re: Metrix MX4940 (Metrel) electrical installation tester
« Reply #5 on: March 25, 2019, 09:57:21 am »
I'm keeping this updated in case it is any use to someone else.
I found an Italian PDF user manual for the HT Italia Plustest HT2043.

Regarding the RS-232 link this says:

Parametri di comunicazione
Formato: 1 start bit, 8 data bits, 1 stop bit, nessuna paritĂ .
Baud rate: 2400 Baud.
Protocollo di trasferimento: xON / xOFF

(1 start ; 1 stop ; 8 data ; no parity ; flow Xon/Xoff ; 2400 bps)

It also shows the link with a 3 wire null-modem (crossed) cable.

Also found the old Metrel software (previously named it wrong, it's called "Installink"), it's a 32bit only MS Windows application.
Anyway, there is no way it will communicate with the MX4940 no matter the settings.

All I have so far is the "Print" capture from the MX4940 (1 stop ; 8 data ; no parity ; no flow ; 2400 bps) using a straight cable and Realterm.

It spits-out data in this format:

MX  4940     No 98032680





L:001     P:001         
   1 A.v.:     .00 m/s 
   2 A.v.:     .00 m/s 

   3 RH:        .0 %   

   4 L.l.:      0  lux 

   5 I:        .14 A   

   6 R:     >1999  Ohm 

LOW Ohm 200mA
   7 R:     >19.99 Ohm 

   8 PHASE R.: 0.0.0   

   9 R:     >199.9 MOhm

  10 R:     >199.9 MOhm

  11 R:     >199.9 MOhm

I'll get in touch with Chauvin / Arnoux about the software and manual although I think I know the answer (if any at all).

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