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Factory Settings Restored.
This message indicates that the CMOS RAM no longer retains any custom Pricing or Game
Adjustment settings and has reverted to factory default settings. Generally, the following CPU
checks will isolate the cause of the CMOS RAM memory failure. The voltage at pin 28 and pin
26 of U8 should be +5V (game turned On) and at least +4V (game turned Off). When the
voltage drops below +4 V, memory reset occurs. Check the batteries and battery holder. Be
sure that the batteries are good and that there is no contamination on the battery holder
terminals. Turn the game OFF, and use an ohmmeter to check diodes 01 and 02 on the CPU
Board. 01 should read 0 ohms when forward-biased and infinite ohms when reverse-biased.
02 should read 15 ohms when forward-biased and infinite ohms when reverse-biased.
Note:
Readings taken from Analog Meter. This message can also indicate that there is an open diode
on a 50V coil, and noise is entering the circuit.
CPU L.E.D.'s
The CPU has three L.E.O.'s located on the upper left side of the board: 019, 020, and 021.
On game power-up 019 and 021 turn on for a moment then, 019 turns off and 020 starts to
blink rapidly. 021 remains on. The system has detected a problem if the following happens:
CPU Board L.E.D. Error Codes
Center L.E.O. blinks one time
Center L.E.O. blinks two times
Center L.E.O. blinks three times
ROM Error U6
RAM Error U8
Custom Chip Failure U9
Sound Board Beep Error Codes
Upon Game Turn-On:
1 Beep
2 Beeps
=
3 Beeps
4 Beeps
=
5 Beeps
=
6 Beeps
=
7 Beeps
=
8 Beeps
9 Beeps
=
Sound Board OK
U2 Failure
U3 Failure
U4 Failure
U5 Failure
U6 Failure
U7 Failure
U8 Failure
U9 Failure
OPTO THEORY
The opto receiver (detector) 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
(emitter or L.E.O.) should always be approximately 1.4 volts. Note, the transmitter (L.E.O.) is
larger than the receiver (it protrudes further from its case).
Transmitter
Receiver
1.0-1 .4 Volts
0.1-O.7V Unblocked
11-13V Blocked
Infrared Ray
WHT
Gray
Black
White
Green
Judge Dredd 1-37