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CPU L.E.O.'s
The CPU has three L.E.D.'s located on the upper left side of the board: D19, D20, and D21. On
game power-up D19 and D21 turn on for a moment then, D19 turns off and D20 starts to blink
rapidly. D21 remains on. The system has detected a problem if the following happens:
CPU Board L.E.O. Error Codes
Center L.E.D. blinks one time
ROM Error U6
Center L.E.D. blinks two times
RAM Error U8
Center L.E.D. blinks three times
Custom Chip Failure U9
Sound Board Beep Error Codes
Upon Game Turn-On:
1 Beep
=
Sound Board O.K.
2 Beeps
=
U2 Failure
3 Beeps
=
U3 Failure
4 Beeps
=
U4 Failure
5 Beeps
=
U5 Failure
6 Beeps
=
U6 Failure
7 Beeps
=
U7 Failure
8 Beeps
=
U8 Failure
9 Beeps
=
U9 Failure
OPTOTHEORY
The opto receiver (Photo Transistor) should be approximately 0.1-0.7 volts when the opto beam is
unblocked and approximately 11-13 volts when the opto beam is blocked. The opto transmitter
(L.E.D.) should always be approximately 1.4 volts. Note, the transmitter (L.E.D.) is larger than the
receiver (Photo Transistor); it protrudes further from its case.
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