ST700 GENERAL HANDBOOK
667/HB/27880/000 Page 88 Issue 8
If any of the voltage monitors appear to be detecting mains, then it would imply that
those triacs are not holding off the mains and the lamp switch card should be
replaced.
L/S Supply Failure:
L/S Monitor Fault
The lamp supply can be detected on the voltage monitors, but no signal is present
from the lamp supply monitoring transformer. Replace the lamp switch card.
L/Supply Failure
No lamp supply has been detected by the lamp supply monitoring transformer but
further investigations by the self-test facility cannot determine the cause. Check the
lamp supply circuits relays, fuses, etc., in and around the power distribution unit.
Also check that the dim connector SK2 is connected. N.B. Links are required on this
connector even if no transformer is required.
Checks that each lamp supply relay can switch off the lamp supply
independently:
SSR Fault
Relay A Fault
Relay B Fault
Failure of any of these tests implies that the relay is not switching off, i.e. that it is
either welded closed or the control signals from the main processor card are stuck
active.
Checks that the dimming relay is functioning:
Dimming Fault
A fault is only logged on the dimming relay if the dim lamp supply is more than 75%
of the normal lamp supply, i.e. that the dimming relay seems to have no effect on the
lamp supply.
Note that this test does not fail if there is no dim lamp supply, e.g. if no dimming
transformer is fitted, since self-test may be performed on the just the controller rack.
Therefore, the dim voltage should be checked manually, e.g.
Dim L/Supply=160V
