ST700 GENERAL HANDBOOK
667/HB/27880/000 Page 85 Issue 8
Figure 22 – Handset
0 = - -
1 = - E
2 = F –
3 = F E
0 = - - - -
1 = - - - A
2 = - - B –
3 = - - B A
4 = - C - -
5 = - C – A
6 = - C B –
7 = - C B A
8 = D - - -
9 = D - - A
A = D – B –
B = D – B A
C = D C - -
D = D C – A
E = D C B –
F = D C B A
So in the above example, there are no voltages on Phase B amber (or Wait). Has
the wait fuse blown?
On power-up, the self-test facility checks the integrity of the main processor
board:
RAM FAULT
DPR RAM FAULT
PRG PROM FAULT
XTL FAULT
DPR R/W FAULT
All the above faults point to problems internally on the main processor card.
Checks communications with the secondary / phase bus processor:
P/Bus CPU....
If the processor cannot be detected, then the self-test will wait indefinitely at this
point with the red system error LED illuminated. Check that the processor and its
firmware are fitted.
Examines the lamp switch cards to see how many are fitted:
No L/S Cards Found
No cards were detected. Either the lamp switch or the processor PCB could be
faulty.
Waits for ZXO synchronisation and checks the mains frequency:
