Hitachi GCR-8480B User Manual page 4

3. Troubleshooting Guide
A. LED doesn't light.
Check Power Voltage (TP1:3.3V, TP2:12V)
Reference Voltage
[TP3:VC(2.5V) and GND.]
Does "H" output in IC501 pin
Check and replace R105, R106, Q12
and LED701 (LED702 for NECCI).
A-1
Is the CLOCK Frequency of IC501 pin
33.86MHz?
Check and replace IC501.
NG
OK
NO
170 ?
YES
NO
54
YES
Check the power input
pattern.
Is the CLOCK Frequency of
IC501 pin ,
93 94
33.86MHz?
YES
Check IC501.
Check and replace X10;
33.86MHz.
NO
A-1
23