Strobe SL34063A

Discussion in 'General Electronics Chat' started by inwo, Feb 18, 2014.

  1. inwo

    Thread Starter Well-Known Member

    Nov 7, 2013
    Repairing a strobe light that uses a SL34063A.

    SL34063A Not running.

    Pin 1 6 7 8 high

    But 5 is at 2.5 volts. It was getting a high pulse from some logic that I opened for testing.

    Pin three has low level triangle wave.

    I was hoping to just throw some parts in and not have to draw out the circuit.

    Replaced SL34063A and IRF540 before doing much testing.
    Most of the other parts have been removed and tested. All except the bad one.:(

    IRF540, its driver, and transformer all seem ok. I can build voltage in secondary circuit by pulsing pin 1-2 with chip removed.

    I don't understand the data sheet reference to comparator 1.25V .
    Is that nominal voltage at pin 5 ?
    I was expecting a wide range.
    If 2.5V is keeping it off, I'll concentrate on that part of the circuit.
    There is a pull down resistor on it.


    Hope posting will help organize my thoughts!
  2. inwo

    Thread Starter Well-Known Member

    Nov 7, 2013
    I should have studied the data sheet before ordering all the parts that I didn't need.:(

    The pulse from a ripple counter wasn't able to pull pin 5 down.
    Needed the 1.1K pull down.

    I swear that's the only part I didn't take out and check with my shotgun approach.

    Hope I find a few more to repair so as to spread my 6hrs investment around.:eek:

    Took another hit to my "it's always the power component" philosophy.