Oki ML490 Maintenance Manual page 134

2 In receiving by serial interface, printing data is omitted or printing operation is not performed.
Are RxD and SSD of Q3 as specified in Figure C-7?
Yes Are, WR, and BUS signals of Q3 pin 3 as specified in Figure C-8?
Yes Is the level of a BUS signals at Q7 pins 2-9 the same as that of DB0-7 when
Yes Is 4 pin of Q6 identical to WR signal in Figure C-8?
Yes Check Q3 in the Control Board.
42114101 Rev.1
No Replace the Q2.
542ns
WR
Q3-3
No Replace the Q3.
WR signal is started?
No Replace the Q7.
No Replace the Q6.
Figure C-8
5V
0V
5V
0V
134 /