Arcade Collecting > Pinball

ROAD KINGS problems [Next step: Drop target]

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RayB:

--- Quote from: Pinball Wizard on December 10, 2010, 08:32:46 pm ---Do this for me: Unplug everything except the single power plug and tell me what the displays do. Then plug everything except the data cable in and tell me what it does.
--- End quote ---

1. Blank displays
2. Blank displays

Does this narrow the problem down to a fault on the main game CPU board?

RayB:
Here is a vid that shows the weird digits. Note how its not "missing segments" on every digit (pointing to a UDN fault), it's digit-specific. Like the data that says a digit specifically needs certain segments is messed up, and its messed up consistently (ie: a zero is missing the top left side segment no matter what position or display its on)

Pinball Wizard:
Do the alpha-numeric displays do the same thing for the ones I sold you vs. the ones already in the machine?

RayB:
Yes. Your displays (player 1 & 2) are brighter and don't flicker like my player 1 does. That's why the video is focused on the two completely working displays on the right. I'm interested in whats causing messed up characters.

I tested the data cable and it's fine.

What's weird you'll notice is the zero. In the video it's missing one segment, but if you look at my photos just above, the zeroes used to be missing two segments.

StephenH:
It appears with the alphanumeric having one segment on on all of them and the numeric having a segment off that the issue is data, not power from this point.   

I would check the following:

1) See if the voltage changes on  each  DATA line input (not power pins) of the cable as the display is powered.  You may also be able to read this also on the input pints leading from the display board cable to the display driver chips on the display board.   Keep searching for one with no voltage change as that sequence is being run that is not a known power pin or unused pin.  When you find this, unplug the game and check the solder joints at that point. 

2) Then, with the game off, unplug the display cable and verify there is continuity from that chip to the display cable connector from the identified chip pin by using an ohmmeter (be sure to get the correct pin on the display cable or connector).  If there is no continuity, you likely have another bad solder joint.

3) Then check the display cable.  Do a continuity check with the cable unplugged on both ends on the identified pin number.  If there is no continuity, replace the cable.

4)  See if the score display is fixed now.

5) If this doesn't work, you may need to track where the pin in question on the motherboard in the display cable jack leads to an transistor or IC on the game motherboard.  Turn on the game and check the voltages on the identified chip pin for any variance.  If there is variance there, check for solder joints between that IC or transistor and the display cable pin identified.   Use an Ohmmeter if needed to verify continuity with the game off.

6) If there is no voltage variance on the pin identified above at the game board output IC or transistor level, then the chip or transistor is likely bad or there is a much more serious problem with the game board.

3)

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