Re: TECH:Rottendog Data East Power Supply DPS004 + older DMD


"chuck" <chuck@xxxxxxxxxxx> wrote in message news:b5382c36-ae0b-4be7-a2f0-44c2d6d59fa4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I picked up a GnR pin with a rottendog power supply board and a non-
working dmd. The power supply board had a blown zener diode and lm317
in the 68 volt section. I replaced the diode with one Jim sent me. I
put the DMD in another machine and it worked fine. I tested the power
output and while not spot on it was close. Fuse blows, diode blows,
lm317 blows. Replaced everything again. Double check everything, the
smell of burning electronics again. Ok, I'm not going to blow a third
set of components. Check everything again. All seems to be working.
Decided to consult with Don (pb2k team) and he suggested I check the
ohms on the display. Sure enough 68v to ground was 38 ohms which drew
too much current and blew the section.

It seems the original wms board is current limted and Rottendog's
board is not. Where this really comes into play is with older
displays that may be on their last leg. Be careful when using this
power suppy with any older display. A new display should work just
fine with it.


LM317AHV is rated 1.5amp. Your display was trying to draw (68/38) or nearly 1.8 amps. Yep, I can see why the LM317AHV was having problems. But, the LM317AHV *IS* internally current limited and will shut itself down with excessive current draw. There is another problem with the LM317AHV design that has been mentioned previously. What you are seeing is EXACTLY the type of failure that was mentioned in prior posts ... but to stay out of an arguement, I won't get into this.

- Ed


.

Relevant Pages

  • Re: Sony HCD-MG510AV 60 cd receiver w/surround and A/V jacks - WONT TURN ON
    ... line for the display is down. ... There is a 100 ohm fusible resistor on the power board, R901, near the large ... There is also a separate fuse board, and there could be bad fuses there - ... Does this diode reading sound suspicious or like soemthing else on the ...
    (sci.electronics.repair)
  • Re: TECH:Rottendog Data East Power Supply DPS004 + older DMD
    ...  The power supply board had a blown zener diode and lm317 ...  I replaced the diode with one Jim sent me. ... put the DMD in another machine and it worked fine. ... power suppy with any older display. ...
    (rec.games.pinball)
  • Re: Diode for reverse polarity protection
    ... by connecting the wrong power cord (reverse polarity) into it. ... IN4001 and it powered up the display and started scanning. ... Any suggestions on another diode to try? ...
    (sci.electronics.repair)
  • TECH:Rottendog Data East Power Supply DPS004 + older DMD
    ... I picked up a GnR pin with a rottendog power supply board and a non- ... working dmd. ... I replaced the diode with one Jim sent me. ... power suppy with any older display. ...
    (rec.games.pinball)
  • Re: photodiode for 500mw laser
    ... I have a 500mw laser diode and want a photodiode for measuring the ... power of this laser diode.if any photodiode is appropriate or some ... I like the black glass method a lot ...
    (sci.optics)
Loading