User Tag List

Thanks useful information Thanks useful information:  0
Results 1 to 9 of 9

Thread: repairing / modifing Yongnuo Triggers

  1. #1
    Member
    Join Date
    01 Mar 2009
    Location
    Brisbane North
    Posts
    150
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    repairing / modifing Yongnuo Triggers

    Hi All,
    I received a set of Yongnuo Triggers and Receivers for Christmas and managed to blow two of the receivers within 30 minutes. It turned out that 2 of the old flash guns I connected them to had trigger voltages around 170V. Needless to say the receivers stopped working very quickly after that after first trigger.

    The high voltage blows the trigger transistor which is situated on the edge of the PCB just under the negative battery terminal. It can be replaced with a BC817 (surface mount NPN transistor for about 20 cents).

    The problem is you still can't use those old flash guns......

    I have modified the circuit and added a optoisolator with a triac driver output (part number MOC3020). These devices are good for around 400V and seem to be able to handle the trigger current. One track has to be cut and one resistor is required for the optoisolator input. (see the pic below)

    I've modified both the 'faulty' receivers and so far I've had no problems. I've triggered the high voltage flash guns well over a hundred times at full power and all is working well.

    I hope that maybe this can help someone else because other than the high voltage, the transmitter / receivers have been working very well.

    Cheers,

    Greg

    Bodies: Nikon D4, D300, D80
    Lenses: Nikon AF-S 18-135 kit lens, Nikkor AF-S70-300 1:4.4-5.6 G VR, Nikkor AF Micro 60mm 2.8 D, Nikkor AF 50mm, 1.8 D, Nikkor AF-S 10-24mm f/3.5-4.5 G ED, Nikkor AF-S 24-120 f/4G ED VR, Nikkor AF-s 500mm f4G ED VR
    Accessories: SB600 Flash, Flashpro 500SP Studio Lights, Sekonic L758D light meter, Manfrotto 055XPROB Tripod, Velbon RUP-43 Monopod, Wemberley Head
    Monitor: Eizo S2231W with Huey monitor calibrator
    Lowepro Slingshot 100AW, Tamrac T31 case, Computrekker AW

  2. #2
    Ausphotography Regular
    Join Date
    08 Nov 2009
    Location
    Brisbane
    Posts
    1,685
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for that. How would you determine the trigger voltage of a non canon flash? I have an old cobra unit
    Alan
    -------------------------------------------
    Canon 5DMkII, Panasonic GF1 and a few other bits and bobs
    My SmugMug


  3. #3
    Member
    Threadstarter

    Join Date
    01 Mar 2009
    Location
    Brisbane North
    Posts
    150
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hi Coolie21,
    A multimeter is the safest, but make sure you get a good connection. (That's how I got caught, I didn't really get to the edge corrector correctly so the first time I measured it the volts looked ok.)

    Be careful when you measure the pins, if it is 170V you will get a small zap if you touch the two trigger points with your fingers.

  4. #4
    Member
    Join Date
    25 Dec 2007
    Location
    At home
    Posts
    190
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    well done greg and thnks for the tip !
    "Knowledge is a single point, but the ignorant have multiplied it."

  5. #5
    Moderately Underexposed I @ M's Avatar
    Join Date
    04 May 2007
    Location
    Marlo, Far East Gippsland
    Posts
    4,864
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    A very useful post Gregory
    I will remember this post for when someone runs into troubles like you did.

  6. #6
    In Training MarkChap's Avatar
    Join Date
    09 Jan 2008
    Location
    Widgee, Queensland
    Posts
    2,228
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by I @ M View Post
    A very useful post Gregory
    I will remember this post for when someone runs into troubles like you did.
    Why not make it sticky at the top of the Strobist forum area ??
    Smoke Alarms Save Lives, Install One Today
    I shoot Canon
    Cheers, Mark


  7. #7
    Member
    Threadstarter

    Join Date
    01 Mar 2009
    Location
    Brisbane North
    Posts
    150
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Somehow I've messed up the link to the photo. The resistor used is a 180R. 1/4watt.


  8. #8
    Member beckett5361's Avatar
    Join Date
    14 Mar 2009
    Location
    Adelaide
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That's really helpful thanks a lot for the Info.

  9. #9
    Member burningmosquito's Avatar
    Join Date
    19 Nov 2010
    Location
    Canada
    Posts
    1
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Thumbs up

    Hello Gregory.

    I found your post on this forum about modifying the RF602 flash trigger, while searching to find if they are safe for high voltage flashes. Which apparently they arent! I really like your idea of adding the MOC3020 opto-isolator!!

    I cannot tell exactly from your description which pins are going to what on the trigger board though. Hopefully you can clarify?

    I found this link describing the isolator: http://uk.rs-online.com/mobile/searc...duct&R=1954116

    From you picture, I cant tell which pin is the anode.. And not completely understanding the circuit and how it is functioning, I'm at a bit of a loss how to wire it up.

    Also, where is the wire on the far left going to (from the resistor to..?). Will I have to remove the board and connect to something on the other side?

    I hope you can provide me with a little guidance for this amazing modification.
    Might want to think about creating a little tutorial and posting it on the strobist.com forums? I think a lot of people could benefit from this mod!

    Thanks for your time,

    Trevor


    PS because I am a new forum user, I cannot send a private message. I hope Gregory reads this. If anyone would be able to draw this post to his attention, I'd be quite grateful! Thanks!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •