Gasboy 1000 Series FMS Diagnostic Manual - Manual (Page 96)

Troubleshooting
03/07/03 6-11 11
Not Completely Dead, RS-422, 1 SHM, No RS-422 Communication
Possible Cause Checks Corrective Action
Defective data terminal. Remove communication cable
from data terminal. Connect
RS-232 loopback jumper to
communication cable.
Perform diagnostic test 5,
selecting port to be tested. Replace data terminal if
diagnostic test 5 passes.
Defective SHM or wiring. Remove field wiring from
SHM. Place SHM in loopback
test position. (If there is no
test switch, jumper TB
positions 1 & 3 and 2 & 4).
Press several keys on data
terminal to see if they will print. Replace SHM or data terminal
communication cable if
selected keys do not print.
Repair wiring between Series
1000 and SHM if selected
keys print.