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Thread: Lexel 88a

  1. #1
    Join Date
    Dec 2006
    Location
    Germany
    Posts
    21

    Default Lexel 88a

    Hi,

    i get recently some Lexel 88a heads.

    Now i have the problem to find out the correct connections which are needed. I checked the "sams laser faq" where i found a schematic (http://www.eio.com/repairfaq/sam/88hsch.pdf) of the head and can "reverse" with these docs some connections but not all and mainly not 100% for sure.

    On the head itself i have these kind of connector: http://www.ewoks.de/laser/l88a_mains.jpg

    On the first look i assume the following connections:

    from right to left
    pin7 (cathode) -> P1W
    pin6 (cathode) -> P1X
    pin5 (anode /hv) -> P1P

    just these ones i recognized (hopefully) right

    Is there perhaps a kind of user manual or something which documents this connector?

    thx in adance

  2. #2
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
    Posts
    3,677

    Default

    We have a rough manual and schematics for the OEM switch mode power supply, nothing on the head tho....
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  3. #3
    Join Date
    Dec 2006
    Location
    Germany
    Posts
    35

    Default

    Hi Ronny,

    some years ago we had arround 30 of them...
    funny to that they are still in use

    I think that i still have the complet documentation of
    them... when remebering it correctly
    the connection is like this (from right to left)

    - Cathode (AC 3V from Fillament Transformer)
    - Cathode (AC 3V from Fillament Transformer)
    - Anode (DC 175V / 20A)
    - Magnet (DC 150V - 180V 3A)
    - Magnet (DC 150V - 180V 3A)
    - Starter (GND)
    - Starter (+12)

    Please make shure that that this informations are correct
    bevor pluging the PSU to the head.
    Start with the 12V for the Starter, you will hear a loud "click" when
    this is working. The Magent will have a resistance of 40-50 Ohm,
    measure if one leg of the magnet has a connection to cathode
    or anode ! For the magent you will need a Transformer or a circuit
    that will switch the magent to the psu when the laser tube
    has started... never connect the magent directly to the psu, because
    the psu will deliver 300V when the tube is not started - this will kill
    the magent !!!

    greetings,
    marco

  4. #4
    Join Date
    Dec 2006
    Location
    Germany
    Posts
    21

    Default

    Hi,

    cool, thx!

    This seems to be ok. The first 2 pins go to the starter (it clicks , btw the 2nd ones i have about 57Ohm and no connections to either anode or cathode.

    When i take a closer look to the magnet wires there is a interconnection to the igniter you can see this on the schematic from sams laser too.

    Is the igniter powered by the magnet voltage?

    Perhaps its easier to have an extra transformer for the magnet supply (to avoid the switch you mentiond).

    thx
    ronny

  5. #5
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
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    Default

    we are using a extra transformer for the magnet power. A much better method IMO
    KVANT Australian projector sales
    https://www.facebook.com/kvantaus/

    Lasershowparts- Laser Parts at great prices
    https://www.facebook.com/lasershowparts/

  6. #6
    Join Date
    Dec 2006
    Location
    Germany
    Posts
    35

    Default

    Hi Ronny,

    yes, the starter get's power from the magnet supply.
    We used the volatage from the psu to power the starter
    and a relais to switch the magnet on after the tube
    has started, this works very well and you don't need
    a large Transformer for the magnet.

    greetings,
    marco

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