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Thread: Can't get a darn thing out of my Flexmod p3 with Beam Suppression

  1. #1
    Join Date
    Jan 2015

    Default Can't get a darn thing out of my Flexmod p3 with Beam Suppression

    Alright guys, figured i'd stop hijacking one of the previous help threads. DKumpula has been great help on there (thanks man)

    But I'm stumped.

    I originally set it up as per instructions, and got the red led, just by placing a meter across the load, set to current (mA). Ok. As DKumpula pointed out theres cut traces on the beam suppression board, along with different firmware on the chip and this "option" essentially MUST be enabled. Well. Seems i forgot to jumper the interlock in the first time around, so, no harm no foul. Even without the interlock, i was still able to set the 0bias current. Couldn't for the life of me get it to go to Gain current. when applying 5V to the modulation.

    Added the 2 resistors, WHILE making sure no shorts were present across the 2 pads.

    Still, only getting 0Bias current. With the red Led on.

    Did some digging. Read some guys having similar issues with running at 5V similar and getting the red led, that it should be around 9V-12V

    Ok! I'm running a 12v/5V switching supply. So. Switched to 12V. for supply and 5V for modulation. Nothing.

    Now when i power up i get NO current and still the red LED. What gives? Also before, the current would spike on powerup. I used this supply before on a 3D scanner and a small driver i made myself. I didnt notice any spikes during powerup on the PSU side. I'll digout my o-scope next.

    I've never even had the chance to hookup my laser. My goal was to set my 2 current levels, nothing crazy. On and off was my goal. Then connect the diode. See it work. Disconnect, go back to the meter, and adjust my currents to where i need.

    Is this thing magically fried now? The fuse is still good. I didn't let out any of the magic white smoke.

    I guess what throws me too is, the manual says if beam suppression is enabled, then interlock and open loop sensing are disabled. What becomes of the red LED fault if those 2 features are disabled?

    If this darn thing is shot, any better suggestions? Single laser, analog modulation, push 1.8A(ish) amps. Something that arrives ya know maybe the same week would be nice too.

    Sorry for the bit of sarcasm/frustration. This project has been cursed from the start! Bum deal on first diode, second diode not being the diameter advertised...requiring a heatsink be turned on a lathe for it..etc. lol

    Thanks in advance guys.

  2. #2
    Join Date
    Jan 2015


    Turns out my meter...something mustve blown in it, which is why i was getting zero current.

    So ok. Now im back to where i was before. Red LED, 0bias current only, no Gain.

  3. #3
    Join Date
    Jul 2013


    I'm having problems with one of my p3's too except I don't have the beam suppression on mine.

    When I received them, one was missing the current sense resistor. I replaced the resistor and now when I try and set my currents I get nothing except a fault LED. I am sure my interlock is closed, I have triple checked that. I have tried setting my currents with just a multimeter and with the diode itself, in both cases the fault LED is lit. I have checked the fuse on the back and its fine. I know my diode is functioning as I tested it off the regulated power supply. The flexmod is powered off the same supply at 12V. It is drawing quite a bit of power at 250ma when powered on.

    I have no idea what to do. Any suggestions?

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