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Thread: Flexmod P3 Review

  1. #51
    Join Date
    Mar 2007
    Location
    Portland Oregon
    Posts
    118

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    Got mine today
    Thank you drlava

  2. #52
    Join Date
    Dec 2006
    Location
    Netherlands
    Posts
    983

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    Got mine today. It was perfect timing because I just came back from the metal shop and it was on the doormat.
    With the instructions that came with it, setup was easy and painless.

    I like the form factor, small footprint made it easy to add to the red module.
    Good quality, making it a joy to work with it.

    I did have to read the instruction paper more than once to find the interlock connection that I bypassed, also the pads for disabling the 7 sec delay, and selecting the 5V supply. After setting the bias voltage and full power voltage, I fired it up with the dual red and it worked perfectly.

    Can do without but I missed is being able to monitor the drive current in operation to be able to adjust it without removing the diodes. I missed it because the bias current adjustment also affects the max setting and I'm used to finding the bias current by observing the diode, and then set the max current to a value that is known as safe.

    thanks drL.

  3. #53
    Join Date
    Oct 2006
    Location
    Cleveland, Ohio
    Posts
    2,342

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    Thanks for your feedback, Zoof!

    Here's a hint, in circuit current monitoring is possible. With the power off, connect the positive lead of your multimeter (in millivolts mode) to the V+ connection on the driver (or the large resistor lead next to the v+) and connect the negative lead of your multimeter to a 1k to 5k resistor and the other side of that resistor to the large current sense resistor on the top of the driver on the interlock connection side. Then power up and the output current will be the multimeter reading * 5. Just don't connect and disconnect the multimeter with the circuit running.

  4. #54
    Join Date
    Sep 2008
    Location
    Orlando, Florida
    Posts
    1,156

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    Got mine installed in my projector and it works great. I got hung up on the interlock wiring too. I don't have an interlock on my projector so I ran a jumper from the interlock solder point to the +V. Since there is only 1 solder point for +V (and I'm using it as +V) I soldered the interlock jumper to the lead closest to +V of the large resistor. This works fine since it is also +V.
    Chris

  5. #55
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,303

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    ahh..

    After one hour of messing.... NOW I find out that I need to connect the interlock to + :O

  6. #56
    Join Date
    Dec 2009
    Location
    Devon
    Posts
    48

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    Got my drivers yesterday. Thanks, Dr Lava for the quick shipping.

    I just tried hooking one up...

    I'm sure the drivers are working fine, but I have a bit of a warning - Beware of cheap 5-volt PSU's !!!

    (To be clear, this is not a fault of the driver. They're obviously well built)...

    I adjusted the driver exactly as the manual says and set the gain to the correct current for my cheap "50mW" green module. I then switched off and made sure I shorted the output wires before connecting the diode...

    Switched back on - bright FLASH of Green then nothing much else after the 7-second delay. (The 808nm diode is probably partially living, but not enough to lase the crystal.)

    I retested everything and thought "maybe it was just static or something"? So, I foolishly tried my LPC-815 diode - bright FLASH of Red then "fancy LED".

    The current output tests fine, so clearly what is happening is that my relatively cheap 5V PSU is outputting a large voltage spike at switch on!! This only seems to happen if the PSU has been turned off for about a minute or so.

    So, when the driver has the 5V jumper soldered, I'm assuming that this bypasses the onboard voltage reg? If the power supply then spikes above spec, would that generate the corresponding current spike from the driver?

    This was just bad luck on my part, but would it be an idea to use a 5.6V zener across the power pins when in 5V mode?

    btw, I realize that when you adjust the bias setting, the maximum current (gain) will also track with it, so I made sure everything was set correctly beforehand.

    Luckily the LPC diodes are dirt cheap. For the Green module, I might try fitting my 1.2W 808nm C-mount diode to it. (I've had a SDL 1.2W diode for years, but never had a decent housing for it).

    Just a heads-up.
    OzOnE.
    "It's like lasing a stick of Dynamite."...
    http://www.youtube.com/watch?v=0ds0wYpc1eM&fmt=18
    Surely all PL members have seen this movie?

  7. #57
    Join Date
    Jan 2005
    Location
    Norway
    Posts
    1,303

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    here is my flexmod and 445 doing just fine in a pretty small projector mount..






  8. #58
    Join Date
    Dec 2006
    Location
    Netherlands
    Posts
    983

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    Is that a TREX-250 up there??

  9. #59
    Join Date
    Oct 2006
    Location
    Cleveland, Ohio
    Posts
    2,342

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    Quote Originally Posted by OzOnE View Post
    I'm sure the drivers are working fine, but I have a bit of a warning - Beware of cheap 5-volt PSU's !!!

    (To be clear, this is not a fault of the driver. They're obviously well built)...
    OzOne, this is a good point. When you put the driver into 5V mode, it bypasses one of the postregulators. So if there is a HV spike from the power supply, it will find its way through the bias circuit and cause problem. You suggest a zener, but infact there IS a zener on the input in 5V mode, but clearly the PSU spike was too powerful to be quenched by this alone.

    Liteglow.. that is one tiny 1W projector

  10. #60
    Join Date
    Dec 2009
    Location
    Devon
    Posts
    48

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    Hi,

    Is there a zener on the actual power pins as well as the modulation input?

    I just tested my PSU using an o'scope and it didn't appear to have a noticeable voltage spike? (it ramps up quite slowly). It's not a storage o'scope though, so the spike might be too quick to see. How would I go about testing the system before I connect a real diode?

    When the diodes blew up, it looked like the bright flash lasted quite a while (~200ms?) and was a similar time for both the LPC diode and Green module - how long does the driver test the bias current during initial start-up?

    I'm currently trying to work out how to mount a C-mount diode into the old Green housing (which originally used a 5mm diode). There was a piece of fibre mounted in front of the original diode for FAC, would the power output take a huge hit without this?

    Thanks,
    OzOnE.
    "It's like lasing a stick of Dynamite."...
    http://www.youtube.com/watch?v=0ds0wYpc1eM&fmt=18
    Surely all PL members have seen this movie?

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