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Thread: CNI lab driver pot assignments (MBL / MGLIII)

  1. #1
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    Default CNI lab driver pot assignments (MBL / MGLIII)

    Can anyone help me to identify the functions of the pots in the CNI MGLIII lab driver?
    The attached pic shows the driver board and the original pot component labels.
    Many thanks in advance..

    Click image for larger version. 

Name:	MGLIII_lab pot assignments.png 
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    Updated:
    Assignments so far from different sources and unconfirmed:

    RA1: LD TEC setpoint
    RS2: LD TEC thermistor feedback gain
    RA2: Crystal TEC feedback gain
    RP2: LD zero bias / idle current

    RP1: ...
    RP0: ...
    RP07: ... (present on the MGL III driver and not on the MBL driver)

    PSU voltage sets diode current
    Last edited by Zoof; 10-24-2010 at 12:04.

  2. #2
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    I can help with some of them.

    RP2 is zero bias

    RS2 is diode TEC

    RA2 is crystal TEC

    Diode current is none of the above. Diode current is set via the driver voltage adjustment pot which is on the PSU board next to the green led.

    Be aware that altering the driver voltage even a tiny amount completely screws all of the TEC settings; be prepared to spend a good half day getting everything back in tune if you alter this.
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  3. #3
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    Quote Originally Posted by Doc View Post
    Diode current is none of the above. Diode current is set via the driver voltage adjustment pot which is on the PSU board next to the green led.
    The plan is to supply the driver board with 5v from another PSU when integrating the lab driver in my new (and smallish) projector case. I was assuming 5V supply and the driver to be independent from the exact supply voltage. I'll need to go back on that assumption.

    Thank you for saving my day, I was unaware of this one!

    edt: In the meantime I've found some more pointers to the pot assignments that confirm your list, will post them later.
    Last edited by Zoof; 10-23-2010 at 23:52.

  4. #4
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    Got some of the assignments filled from various sources. The first post is updated with them.
    Particularly helpful was a schematic from Prism Entertainments / Jim Boylan for an older TTL driver. It showed a `RS1' pot that is not found in the MGLIII version, but on the MGLIII, the RP2, RP1, RP0, and RP07 pots appeared. Any further help in identifying the pots will be much appreciated.

  5. #5
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    Quote Originally Posted by Doc View Post
    Diode current is none of the above. Diode current is set via the driver voltage adjustment pot which is on the PSU board next to the green led.
    Oh my god, you're joking...?!
    Chinese hardware seems to be very very low-cost

    @all
    Supply voltages should NEVER control the diode current. The voltages can change with temperature, amount of load etc., no matter which PSU from which manufacturer you choose.

    Cheers, Leander
    Buy your drivers at www.laserparts.ch

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