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Thread: Lasever PS-II analog or TTL ??

  1. #1
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    Angry Lasever PS-II analog or TTL ??

    Hi,

    A'm using the Lasever PS-II power supply for my DPSS ML671 . I read somewear that this power supply can do analog blanking? I did know that! How can I switch to analog with this module?

    Please let me know...

    Greetings from Holland,
    Vince

  2. #2
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    Feed it 3V from two 1.5V batteries. See if that gives you a beam with a brightness between what you get for 0V, and what you get for 5V. Hopefully, 5V should be the brightest, and 0V should be blanked, and 3V should be roughly half bright.

  3. #3
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    Hi Doc,

    Thanks for your answer!
    I tried it but 3 volts gives 100% light.
    I used also other voltages and the 'turning point' of 0% and 100% is around 2.5 volt. So this is called TTL modulation, I know.

    But how can I tell the power supply what kind of modulation I want.
    I can't see no switch or something to switch over to analog or TTL.

    I think I have just a power supply with TTL

  4. #4
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    That may or may not work. Depending on where the threshold is if its ttl only. If 3VDC is above the threshold then you will get a beam, if its below, then you wont, yet it may still be analog depending on how linear the output is compaired to the input. Which I have found they are not very linear at all. If its analog, you may not start getting a beam until you get to 3.5 volts, just all depends. Best thing to do, is attach +V and -V of a 5V supply to either side of a pot and run the wiper to the input of the driver and -V to common. Then slowly turn the pot and see what happens. You should probably use about a 10K pot. If you find a spot where the beam pops on to full brightness then its TTL only and may need a bit of modifying to make it analog. I'm not familiar with that driver you have linked to, but I do have thier smaller driver that doesn't have the current reading and it is analog.

    David

  5. #5
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    Opps, you replied to his reply while I was typing my reply! Sorry to hear that it is TTL only, but it may still be able to do analog with some modification. Someone out there with that driver may chime in with a mod for it. If given the choice, you should always go for an analog driver, so that it could be run with a TTL source or analog source without changing anything.

    David

  6. #6
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    My test was deliberately crude, designed to be safe and fast and easy, and the second consideration was it was likely to tell something. If it made no difference between 3 and 5V, it either means a TTL (schmitt trigger, as in this case I think), or a VERY non-linear analog, which would need more investigating than any simple test might show.

    What can be a good first test is three 1.5V batteries and a potentiometer. Potentiometers aren't usually as easy to lay hands on as batteries though.

    Edit: I mentioned hacking the soft start circuit as a way to get analog modulation. (Other thread in this bit of the forum.)
    Last edited by The_Doctor; 04-30-2007 at 09:47.

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