Oki OKIPAGE 8p Maintenance Manual page 154

B-7 Data sent through the Parallel I/F cannot be received.
• Is the signal at Pin 11 (BUSY-P) of CENT connector being at low level?
• No
• Yes
• Yes Is the level of the signal at Pin 1 (STB-N) of CENT connector changed at data
reception?
• No
• Yes Are the signals at Pin 1 (PACK-N), Pin 5 (PERROR-N) of Q4 (74LS07) being
respectively at low level and high level in on-line mode?
• No
• OK?
• No
• Yes Failure of CPU
Is the signal at Pin 13 (BUSY-P) of Q4 (74LS07) changed as shown
below, at data reception?
BUSY-P
• No Failure of CPU
Replace Q4 (74LS07).
Make sure of the connection of I/F cable or the operation of the h ost
computer.
Replace Q4 (74LS07).
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