Pincoder Diagnostics Inc.  Version 2022.11.24.2050_beta

ROM NAME
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01a-leds (Williams sys6a)



PINCODER ADAPTER SETTINGS
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JP1   JP2   DIP SWITCHES

1-2   1-2   ---1--11




PURPOSE
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Tests LEDs on motherboard.



EXPECTED RESULTS
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Top and bottom LEDs should alternate flashing.



IF YOUR BOARD PASSES THIS TEST
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It means the CPU is working and that it can read data from the socket where this test chip
is installed, and that it can talk to PIA1 and IC2 enough to show you activity through the
LEDs. Congratulations! You have a minimally running board.

Before you move on to the next test "blanking", keep this test running and check TP4 with a
logic probe. It should be held LOW with no pulsing. This means the BLANKING circuit is NOT
allowing lights, displays or solenoids to operate, which is what is expected for this test. In
the "blanking" test you should expect to see the opposite result (TP4 is held high with no
pulsing).

    NOTE: The General Illumination (GI) lights are not connected to the Blanking circuit and
    therefore will illuminate during all of the pincoder tests. On some games the GI lights
    are connected to a relay which is controlled by the driver board. You can test that relay
    when you get to the solenoids test ROM.




IF YOUR BOARD FAILS THIS TEST
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Check the board for the following:

    1) Check for pulses (alternating high/low signals) on IC1 pin 5 (VMA). This is important
    because it shows the CPU is executing instructions.

    2) You should also be seeing pulses on IC8 pins 14,13,3.

    3) There should be pulses on IC18 Pin 6 (PA4) and pin 7 (PA5). If not PIA1 *could* be bad.

    4) Check that IC18 pin 39 (PIA1-CA2) is high and that IC7 pin 10 is low. If not IC2 will
    not light the LEDs.

    5) Check that IC2 pin 15 is low enough to be considered a logic 0 and that SW2 is
    open. Check that R19 is 4.7k and is connecting to ground on one side.



IF YOU ARE STILL SEEING NO LED ACTIVITY
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PIA1 could be bad or there may be one or more chips blocking the signals on the address bus
and/or the data bus.

Since PIA1 controls the LEDs, displays and switches, you need to run a test that:

    * Does not use PIA1, and

    * Does not require working displays or user input from switches.

The test you are looking for is "solenoids".

The "solenoids" test enables the flipper relay at startup, so you only need to power it on and
check that the flipper relay is energized. Of course you can also press the flipper buttons
and the flippers should do their thing. If you can do this then the CPU, address bus, and data
bus are fine, and the problem is quite likely PIA1.

If the CPU appears to be working but the "solenoids" test does not energize the relay then
try the "bus" and "tranceivers" tests. Fix any problems you find with those and run this test
again.

Pincoder Diagnostics Inc. Version 2022.11.24.2050_beta
