Help with HV power supply

Discussion in 'General Electronics Chat' started by will1234, Nov 4, 2009.

  1. will1234

    Thread Starter New Member

    Nov 10, 2007
    Hi everyone,

    I recently purchased a (new, old stock) Kaiser Systems LS-1000 1.5kv
    power supply on eBay and am having trouble getting it up and running.
    The interface is via a DB-15 and the pin out is listed below. In
    manual a short checklist is provided on the minimum signals that are
    required to operate the power supply (further below with specifics of
    what I did to accomplish each step). It looks pretty straight forward
    to me but I have been wrong before.

    One point of confusion I have is with the indicator (pins) I want to
    connect LEDs to. If the signal is pulled to ground when the LED should
    be on would that imply that the other leg would be hard wired to a
    current limited 12v (may have to divide it a couple of times). The
    LED would light when the the negative side is 'pulled to ground'?

    No where in the manual have I seen anything defining the input range
    for the voltage program pin 5. If using the 12v reference it has to
    be 12 or below. Right?

    I have to be shooting myself in the foot somewhere in this process I
    just can't tell what I'm doing wrong.

    Any thoughts will be greatly appreciated.

    DB-15 PIN Out

    pin 1 - Inhibit - The high voltage (HV) output is inhibited when
    pin 1 is at +12v or open circuited, it is enabled when pin 1 is
    pulled to ground.

    pin 2 - Load fault indicator - Pulled to ground when the unit
    can not charge the output capacitor to the requested voltage within
    a reasonable time period. The high voltage output is disabled.

    pin 3 - Temperature fault indicator - Pulled to ground when the
    internal temperature exceeds a safe operating level. The high
    voltage output is disabled.

    pin 4 - Interlock Fault indicator - Pulled to ground when the
    external interlock is violated. High voltage output is disabled.

    pin 5 - Voltage program - A positive dc voltage applied to pin 5
    controls the output voltage set point. Input resistance >= 200 kohms.

    pin 6 - Over voltage fault indicator - Pulled to ground when the
    maximum output voltage exceeds a safe operating level, the unit is
    disabled when this occurs.

    pins 7,8 - Voltage monitor - The voltage at pin 8 is a buffered
    signal proportional to the instantaneous output. Drive capability:
    10 V at 1.5 mA.

    pins 9,11,12 - +12 V Control reference - Pin 9, 11, and 12
    provide 12 Vdc that may be used with an external potentiometer for
    supplying a voltage program signal to pin 5. No load regulation:
    1% typical. Output resistance: 10 Ohms. Max output current: 50 mA.

    Pin 10 - External interlock - Pin 10 is provided for use with
    an external mechanical contact to prevent inadvertent supply operation
    when end user access doors are open. Short pin 10 to ground return
    pin 15 to allow operation.

    Pin 13 - End of charge indicator - Pin 13 is pulled to ground
    when the output voltage is equal to or greater than the program

    Pin 14 - Unused

    Pin 15 - Ground - Pin 15 connects to the circuit ground of all
    internal circuitry and is internally tied to chassis ground. The
    return signal connection for all interface connector pins (1 - 13)
    should be made to pin 15.

    Minimum Steps To Operate

    The minimum signals required to operate are inhibit, voltage program,
    and external interlock.

    Step 1: Inhibit the power supply by applying either a high impedance
    (such as an open collector driver in the off state) or a +12V signal
    to the inhibit pin.

    I have used a 12v, 300mA variable wall transformer connecting its
    ground to pin 15 and the +12 to pin 1. I have no idea if this
    is a valid way to do this however.

    Step 2: Apply AC to the power supply (110v).

    There are signs of life because the fans spin up.

    Step 3: Set the desired output voltage by applying a dc voltage to
    the voltage program pin 5.

    I used the 12v reference signal on pin 9 and a Radio Shack cermet
    potentiometer (271-0342) to sweep back and forth across 0 - 12v with
    no change in the power supply HV output. (which is showing an output
    voltage of 24.29v on my multimeter when powered on regardless of the
    pin settings). One thing I did notice is that when all of the pins
    are set correctly and the supply should be operating, when I am
    the pin 5 input voltage I hear a slight ticking sound within the
    somewhere. If I power it down then back up (not changing the pin 5
    voltage) the ticking is not present.

    Step 4: Close the external interlock by shorting pin 10 to 15.

    Step 5: Enable the high voltage output by pulling the inhibit line,
    pin 1, to the correct logic level.

    For this I remove the +12v on pin 1 and short it to pin 15 ground. Again, I may be wrong