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Author Topic: EWM Tetrix 180 Tig welder repair  (Read 7073 times)

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Offline Xaero1982Topic starter

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EWM Tetrix 180 Tig welder repair
« on: November 15, 2014, 07:43:03 pm »
I am trying to repair an EWM Tetrix Tig welder from around 2009. 

The welder powers on, but only displays error code E 5 - overvoltage.  The manual says to check mains voltages, but that is within spec.
Does anyone have any hints about where to start looking?  The schematics in the manual are very simplified, so I'm a bit stuck.

This thing is a pain to disassemble, so I want to take some more measurements before I start tearing it apart.  Because of that, I only have a few
images of the main power board while in the machine.

I know it's not much info, but any hints would be very appreciated.


Operators manual can be found here: https://www.ewm-group.com/ewm-data/partner-web/Betriebsanleitungen/099-000097-EWM01.pdf
Error codes on page 74
Schematics on pages 79-80

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Offline Xaero1982Topic starter

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Re: EWM Tetrix 180 Tig welder repair
« Reply #1 on: November 16, 2014, 02:38:09 pm »
Took some quick measurements today:

AC input - 230.5V
UD+ to UD- = 320V DC
UD+ to PE = 215V DC
UD- to PE = 105V DC
SPW+ to SPW- = 320V DC
SPW+ to PE = 215V DC
SPW- to PE = 105V DC
Could not get any reading between TP and TM

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Offline Xaero1982Topic starter

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Re: EWM Tetrix 180 Tig welder repair
« Reply #2 on: November 18, 2014, 08:57:41 pm »
After e-mailing EWM, I measured between pins 5 and 6 on connector X1. (Lower left)  This was supposed to give -15v, but I measured -30v and decreasing.
Pin 5 (UZWK) comes from the marked pin on the transformer, and pin 6 seems to go through the five caps and to the same area.

I have desoldered and tested the MOSFET and the black diodes in the area, and they seem fine.  All of the caps look good, but I haven't tested them yet.
Any input on what could be wrong would be appreciated. 
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Offline mjrpainless

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Re: EWM Tetrix 180 Tig welder repair
« Reply #3 on: November 18, 2014, 10:35:02 pm »
Buy seem fine, do you mean that they looked fine, or they actually tested fine?
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Offline Xaero1982Topic starter

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Re: EWM Tetrix 180 Tig welder repair
« Reply #4 on: November 19, 2014, 06:41:51 am »
The MOSFET turns on and off, and the diodes measure ok.
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Offline Xaero1982Topic starter

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Re: EWM Tetrix 180 Tig welder repair
« Reply #5 on: November 30, 2014, 05:51:38 pm »
Connected my oscilloscope to the -15v line before filtering, and got this strange waveform.  Then I connected my scopemeter to the primary side of the transformer and the waveform is similar. 
Is this to be expected, or should I investigate this further?
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Offline poxxxy

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Re: EWM Tetrix 180 Tig welder repair
« Reply #6 on: February 03, 2015, 12:47:41 am »
Any other boards in there?

Perhaps one with more mosfets and heatsinks or is it an IGBT based welder?

I have problems with a chinese build welder myself here and hoping I may find some help :).
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Offline LabSpokane

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Re: EWM Tetrix 180 Tig welder repair
« Reply #7 on: February 03, 2015, 03:38:46 am »
If the voltage is incorrect at the current transformer X1, wouldn't be a safe assumption that the problem lies between there and the mains input? 
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