BOC Transtig 375 problems

  1. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,452
    Location:
    Scotland
    I bought an old BOC Transtig 375 ages ago, and for one reason or another I've never used it until today.

    Unfortunately it seems to have a problem where I have to have it set to max amps on AC to burn a 3.2mm rod on arc mode, never tried it on tig but the seller did tell me that it had some issue on tig mode but I cant remember the details now.

    On DC it will hardly even strike an arc, regardless of how high I set the amps. Ive attached a pic of the front to show the settings for anyone familiar with these machines.

    Any ideas?

    DSC_0026.JPG
     
  2. Tom O Member

    Messages:
    327
    Location:
    Canada
    Could be the capacitors I had 1 out of 6 give smoke and replaced all of them on a 130 miller
     
  3. Dominic Muscat New Member

    Messages:
    3
    Location:
    Gozo, Malta.
    Hi, I have a Murex Transtig 375s and I think I have the same problem as you have. My electrician says there is a problem with one of the ICs on the main board. Did you manage to sort out your problem? Do you recommend someone who supplies the boards for these welders?
    Thanks.
     
  4. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,452
    Location:
    Scotland
    Hi, I think the Murex and BOC machines are different? I was off the understanding that the BOC didn't have any electronics
     
  5. eddie49 Member

    That is correct, the older BOC machine has no PCBs in it. There are 4 transistors, but all the sequence control is by relays and the current regulation control uses a magnetic amplifier ( transformer ).

    BOC became Murex and is now owned by ESAB. You could try to contact them, in case they still have parts for these very old machines.
    https://www.esab.co.uk/gb/en/index.cfm
    Maybe Westermans still have parts, or could arrange to have your PCB repaired:
    www.westermans.com
    The manual, including basic circuit diagram, is here:
    http://murex-welding.co.uk/manuals/other/Instruction Manuals/Transtig ACDC275S-375S.pdf
     
    scottmk1 likes this.
  6. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,452
    Location:
    Scotland
    Thanks for clearing that up @eddie49 do you have experience with these machines?
     
  7. eddie49 Member

    Err, no, not really, I just have generic electronics knowledge. I do in fact own a Murex Transtig - bought before I knew how heavy it was or how many Megawatts it uses.
     
  8. eddie49 Member

  9. zeppelin builder

    zeppelin builder Member

    Messages:
    1,501
    Location:
    peoples republic of scotland
    i see you have it set on the lower range
    try it flat out

    is your power supply ok some of them dinsosaurs are single or split phase
     
  10. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,452
    Location:
    Scotland
    I tried it on both ranges and even on max setting it would hardly burn a 3.2mm rod. Power supply is 3 phase and is ok
     
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