ST750
G
ENERAL
H
ANDBOOK
667/HB/33750/000
Page 108
Issue 6
ZXO Sync’d...
If the phase bus processor cannot synchronise to the mains zero cross-over signal,
then self-test will wait indefinitely at this point with the red system error LED
flashing.
Mains Freq Error
If the mains frequency is more than 5% out from either 50Hz or 60Hz.
•
Checks all the ADC test voltages on all of the lamp switch cards:
ADC Tests....Failed
ADC Test Readings
0.0V 2.5V 5.0V
B0+ nnnn nnnn nnnn
B0- nnnn nnnn nnnn
... .... .... ....
If the test fails, then the readings from each board, taken at both the positive and
negative mains peaks for each of the two test voltages (0V and 2.5V) are displayed
on the handset.
Ideally the values should be 0 and 128.
•
Checks that the lamp supply and voltage monitors are detecting no mains:
L/Supply Off=240V
L/Supply Stuck On
If a lamp supply is being detected, then this implies that the lamp supply relays are
all switched on (very unlikely) or the lamp supply monitoring transformer (on the
power distribution card) has failed.
V/Mons Off...Failed
R-000000001
A-000000000
G-000000000
If any of the voltage monitors appear to be detecting mains, even though the lamp
supply and all the triacs are switched off, then this implies a problem with the
hardware on the lamp switch card.
•
Initialises the phase bus processor: