Pincoder Diagnostics Inc.  Version 2021.03.31.1434

ROM NAME
==============================================================================================

05-displays (Williams sys346)



PURPOSE
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This ROM displays different numbers in various patterns on the P1-P4, CREDIT, and MATCH
displays.

    NOTE: This test requires working RAM, and BLANKING signals. Make sure your board passes
    all of the earlier tests before running this test.




PROCEDURE
==============================================================================================

Turn on the game and watch the displays as they sequence through various digit tests.



EXPECTED RESULTS
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While the test is running observe the displays and look for irregularities in what is shown.

The first and fourth digits on the Master display do not light, ever. This is normal as they
are not physically connected and cannot be driven by software.

Some slaves displays (P1-P4) can interfere with other slaves. If you are missing some segments
on the slaves then disconnect all but one of them. Then try the other slaves individually
before trying two or more at a time. The same is true if some segments are too bright.



HOW THE DISPLAYS WORK
==============================================================================================

Of all the possible digits on all displays (P1-P4, CREDIT, MATCH) only two are ever lit at one
time, and it takes a brief amount of time for each segment to turn off. When the displays are
refreshed fast enough they all appear lit simultaneously.

The two digits to be refreshed are determined by the MASTER DISPLAY STROBE OUTPUTS. Player
displays 1 and 3 are linked together, 2 and 4 are linked together, and likewise for CREDIT and
MATCH. For example the leftmost digit on player 1 and 3 are refreshed at the same time. Then
the digit to the right, etc.

The value of the digits to be refreshed are determined by the MASTER DISPLAY BCD OUTPUTS. The
high 4 bits determine the value of the first digit to display and the low 4 bits determine the
value of the second digit to display.

So if the STROBE OUTPUTS are a one (in binary) and the BCD OUTPUTS are 37 (in BCD) the
leftmost digit of the Player 1 display will show a "3" and the leftmost digit of the Player
3 display will show a "7".  If the value for either digit is "F" then the display is not
refreshed with anything and should stay unlit.


    NOTE: If any of the digits on any of the displays are missing segments (ie a zero looks
    like the letter U, or a six looks like a five) then there is trouble on the Master Display
    Board. You can swap cables around between the player displays and the missing segments
    will follow. In this case look for burnt resistors on the Master Display Board and replace
    them.


Pincoder Diagnostics Inc. Version 2021.03.31.1434
