Power Supply

Fault Symptom:

Blank display

Important: The lamps and display can be lit for test purposes using an ISAT, provided that the +15 leads and ground connections are OK.





Action

1 Check the fuses.

2 Check that a +30 power supply is present across pins 1 and 21 and a +15 power supply across pins 37 and 21.

3 Check that no other instrument lamps controlled by the rheostat are on. If other lamps are also affected, it is highly probable that the rheostat is at fault.

4 Check the supply of current to the rheostat. if the current supply is OK, the fault is either in the EDU lamps or the EDU control module itself if the current supply is OK, continue with point 5

5 Check the leads connected to the rheostat.

Signal levels