Strobe lamp fixing

Discussion in 'General Electronics Chat' started by Luigi Capuano, Nov 10, 2015.

  1. Luigi Capuano

    Thread Starter New Member

    Nov 10, 2015
    3
    0
    Hello guys!
    A friend of mine gave me a strobe lamp to fix (an economic one, 1500W) that he would repair.
    The lamp doesn't have a brand on it, but googling I figured out that it's a really common model produced by many brands (KARMA, Proel ecc.).
    My first problem is that my friend disconnected the cables from the PCB (the supply cables and the 3 cables of the strobe lamp) and he doesn't remember how they were connected. Since I can't find a scheme of the circuit I can't find out how they should be connected.
    Is anyone available to give me a help fixing the lamp?
    I attach pictures of pcb and wires.
    lampada1.JPG lampada2.JPG lampada3.JPG
     
  2. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    The xenon tube should be in parallel with the high voltage capacitor(s). A third lead for triggering the tube is just in proximity with the tube and fires it by electric field - that comes from the bit that looks like an old "pie-wound" RF choke.

    You'd need to give a bit more detail about the PSU arrangement to figure that out.
     
  3. Luigi Capuano

    Thread Starter New Member

    Nov 10, 2015
    3
    0
    Hello! Thank you for your reply and sorry for the late.
    What details do you need about the psu?
    The circuit is powered directly by alternative current (there is also a 15A fuse) through the brown and red wires.
    Can you tell me which are the high voltage capacitors just watching the pictures?
    Thank you in advance! :)
     
  4. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
    745
    The high voltage capacitors look like the the two Red ones in pic3, the pulse transformer is the coil on the far left side.
     
  5. Luigi Capuano

    Thread Starter New Member

    Nov 10, 2015
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    0
    "The tube is directly in series with the mains, via the large diodes D2, D3. This is common; once fired, the tube can conduct for (at most) one half-cycle. On the second half-cycle the diodes block and the tube has time to extinguish. C4 is accross the tube (and seems to be charged through C3 and a diode). When the tube fires, it will absorb all the energy from C4 and then contuniue to conduct for the rest of the half-cycle.
    The trigger pulse is produced at the secondary of T1 and applied between Lamp2 and the Trigger terminal. To generate this pulse, Q1 conducts and discharges C1 through the primary of T1 into Neutral. C1 is then re-charged via D1 and R1 from the Line conductor. Q1 looks like it might be a Triac and is driven by Q2 via a capacitive coupling C5. Could this be a relaxation oscilator? I'm not sure if Q2 is driven from the DIP16 or the optocoupler... It's hard to be know how the control is done."

    I had this explanation on another forum, I attach also the picture.
    What do you all think? Should I consider it reliable?
    strobe.jpg
     
  6. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
    745
    do you have the capability to draw the circuit out,it would be easier to repair or work out how to connect it ,
    i bet the ic is a 556 dual timer.?
     
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