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Thread: PCAOM comparison opinions wanted

  1. #1
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    Default PCAOM comparison opinions wanted

    Hi, Folks

    I have a NEOS 8 channel PCAOM with 5 watt crystal.
    I've had to have the RF modulator repaired once and it looks like I have to once again. The RF modulator is the digitally synthesized ( tuneable) type so I can program any channel for whatever wavelength I want.
    I'm using shielded 25 conductor cable, grounded only at the RF modulator end per normal noise interference practices.

    I was wondering If anyone has had any similar failures and need for repair because one color is acting up or you only see red.

    Anyone ever work with PCAOM's from AA or Crystal tech ?

    I'd be interested in knowing your stories.

    Rick
    Profile Redacted by Admin @ 04.24.2010

  2. #2
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    Default

    A few questions... which model of NEOS driver are you using?
    Are your color signals sent differentially? What are you using to
    drive the PCAOM (Pangolin, etc...)

    I would examine your source first to see if your voltage spikes,
    IMHO the NEOS drivers aren't tolerant of overvoltage at all.

    In terms of which I prefer, I prefer the "old" crystal selectable drivers
    since you can do the math, select the right crystal and get perfect
    crystal locked frequencies.

    Let us know!

  3. #3
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    Default

    I have the NEOS model " N64040-75-.1-8CH-16M " which is not the rack mount one. I have to provide the power supplies which are heavy duty linear types with no switching noise.
    I'm driving them with both my older Pango Pro QM32 and the LD2000 basic in unbalanced (non differential mode) so voltage swing should not exceed 5 volts TTL level.
    I had a look under the hood and there's lot of CMOS chips inside the driver.CMOS is very static sensitive and I think NEOS choose poorly there but they must have had good reasons.
    Too bad their manuals don't mention precautionary actions. I pretty much treat all electronics with respect when it comes to static electricity and hope they don't get "wounded" by static hits or noise/power spikes.
    Static damage can manifest strange symptoms ( work fine one minute and not the next, IE. ok at the factory but fail when you try it. Sorta like taking a sick kid to the doctor (what cough ?).
    I musta got a wounded PCAOM since it only worked for about 30 hours the first round before the green lines started strobing. Argh !
    Profile Redacted by Admin @ 04.24.2010

  4. #4
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    Strobing? check your crystal for bonding problems or cracks.

    The TeO crystal is modulated acoustically, so the standing waves
    are what affect the diffraction burst. If a color line strobes and your
    regulators are working, and the other color lines work, then I'd look
    for a problem in the PCAOM itself which would prevent a consistant
    wave from occurring...

  5. #5
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    The green line strobing was a symptom of the first time i had repairs done. I had sent in both the crystal and the RF driver. It supposedly passed all their tests. I only put another 50 hours on the system before I started seeing green line strobing again. I had requested a failure report but they have a communications problem ( or Ignored my request) and I never received any report.
    I had also asked them if they have any handling or setup precautions, specific procedures to avoid any more damage and no reply on that request either.
    Since i moved and tried setting up ,It has degraded and this time all i get is red no matter which line I try to pass.
    Guess I'm going to get another RMA# and return it once again . It cost me $270 US last time , not impressed .
    Profile Redacted by Admin @ 04.24.2010

  6. #6
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    Oh yeah, how big of a laser are you running through here?
    NEOS is a royal pain to talk with... they're definitely not the company
    they were 10 years ago, thats for sure...

  7. #7
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    Default

    Hi LaserLover,

    I have a lot of experience with NEOS PCAOMs. In fact, in 1992, I was involved in the design of their original 6-channel driver. The 8-channel driver that you have is more modern of course...

    From the symptoms you describe, I would say it is time to send it back for repair. Normally the repair charge is quite low, but my experience has been that NEOS turn around time is not all that fast. Maybe if you continually called them and sort of made yourself a pest, they would turn it around more quickly. In the cases where we had to have PCAOMs repaired by them, it wasn't a priority so they took their sweet time.

    As for a "comparison", my opinion is that the PCAOMs put out by A.A are the best, but (as far as I know -- unless something has changed) due to a US patent held by Manhar Shah and licensed exclusively by NEOS, the A.A PCAOMs theoretically can not be sold into the US.

    NEOS would be my second choice of a PCAOM and we have several of them at Pangolin.

    I would not buy anything besides A.A or NEOS. I think MVM may be out of business now, or they are just darn hard to get in touch with. And I thought Crystal Tech stopped making PCAOM by 1995 or so. I certainly haven't seen anything from them recently...

    Best regards,

    William Benner
    Pangolin Laser Systems

  8. #8
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    Thanks for your opinion Bill,

    I sent the NEOS 8 channel module and PCAOM crystal in for repair.
    I emailed them twice since just to confirm that they received my system and no reply yet .
    I guess I'll have to call like last time.

    I have used both my Pangolin-Pro QM32 and Pango QM2000 basic to drive the PCAOM and wonder If there's anything I'm doing that might cause what I think is premature failure to the PCAOM.
    The operation manuals from NEOS are sparse at best and do not contain any precautions or best practices to avoid damaging the system.
    I guess they need the additional income from repairs.
    I'm not impressed with NEOS whatsoever.

    Rick
    Profile Redacted by Admin @ 04.24.2010

  9. #9
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    Hi Rick,

    Honestly, I doubt it is anything you are doing. There are so many Pangolin and NEOS users out there with no problems. If you ask Warren at NEOS what the problem is with your PCAOM, he will probably be able to tell you.

    NEOS had a rash of bad power supplies at one point in time. Are you using their power supply or your own?

    Bill

  10. #10
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    Default

    Hi Bill,

    I opted for the RF module and use my own heavy duty linear power supplies so never ran into any of the NEOS power supply problems.
    It's been over a month since I shipped my system and still no reply from NEOS despite several emails. I get the impression they don't care one way or another. If I had to start over I would NOT have purchased anything from NEOS simply based on their poor customer service .

    Rick
    Profile Redacted by Admin @ 04.24.2010

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