NORTHROP GRUMMAN NAVITWIN IV, Operation, Installation And Service Manual

Page: 108 / 164

056360/E NAVITWIN IV
8-4 Location of Parts on the NAVITWIN IV PCB
Diagnostic LED Indicators
As an aid in troubleshooting, a number of diagnostic LED indicators are
provided on the NAVITWIN IV PCB. These indicate the presence of sup-
ply voltages, activities on the serial data I/O lines and the current states
of the status I/O ports.
Table 8-1:
Diagnostic LED
indicators
LED Colour Indication
CR 13 green flashes with activity on Tx line, ser. data RS-422 1
CR 15 green flashes with activity on Tx line, ser. data TTL
CR 16 green flashes with activity on Tx line, ser. data RS-422 2
CR 21 green flashes with activity on Tx line, ser. data RS-422 3
CR 29 green lit when +3.3 VDC (Vcc) on-board supply present
CR 30 green lit when +5 VDC on-board supply present
CR 32 green lit when –12 VDC on-board supply present
CR 33 green lit when +12 VDC on-board supply present
CR 34 green lit when status input closed, Ext. Dim+
CR 35 green lit when status input closed, Offset 180°/ Ext. Dim-
CR 36 green lit when status input closed, Auto/Man
CR 37 green lit when status input closed, Mute
CR 45 green flashes with activity on Rx line, Gyro 2 input
CR 46 green flashes with activity on Rx line, Gyro 1 input
CR 48 green lit when status output active, G1/G2
CR 49 green lit when relay attracted, K3, watch alarm trigger
CR 50 green lit when relay attracted, K5, off heading alarm
CR 52 green lit when relay attracted, K4,
power failure / general alarm
CR 53 green flashes with activity on Rx line, Gyro 3/Mag input
CR 54 green flashes with activity on Rx line, Auto/GPS input
CR 57 green lit when status output active, G/G3
CR 58 green lit when status output active, G/M
CR 59 green lit when relay attracted, K2, heading diff. alarm
CR 75 green lit when relay attracted, K1, mute output
CR 76 green flashes with activity on Rx line, central dimming
CR 78 green lit when relay attracted, K6, GAS alarm output