Re: Pharoah Score Displays

On Sep 24, 11:30 am, smcc...@xxxxxxxxxx wrote:
Hi there,

  My Pharaoh system 7 williams has problems with the 1st, 2nd and Ball
in Play displays.  Instead of 0 it puts a 4. Instead of a 1 it is a 5
and so on.  I swapped out the Display Driver board and no difference.
If the problem is on the CPU does anyone know what it is?

Thanks,
Sean

2 chips on the CPU are dedicated to the displays. IC 18 is the Display
PIA, IC6 is the BCD converter. IC28 & 29 are just resistor packs. I
would check the connectors at 1J7 and 1J8. Try reseating the
connectors. Have you reflowed the pins in case the solder joints are
cracked?

If you have logic probe, you can check the output during the display
test. If you are getting the wrong digits, it could be the BCD
decoder, IC6. You need documentation on the BCD Decoder and the
udn7180 segment driver. You can map the digit you are seeing the
digit you are supposed to see. By mapping the errors you may be able
to detect which data line is at fault.

Tim
.

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