when the power supply voltage of the power source at station 1 is less than -38 volts the equipment start to give out of frame alarm and when testing the out optical power of the 155/622 H was normally , even looped back the optical board of 155/622 H we still have R-LOF alarm.
we can''t login site 1 from the far end station (station 2) and the indicators lamp of the ss43scb of station 1 will continual on without any flashing.
after that even the power supply source of station 1 is normally ( -48 volts ) also we can''t login the site from far station 2 and stay have R-LOF alarm at station 1 , to log in normally we need to power off the equipment and power on again.
check the source of power supply of the equipment when it is normal we test the equipment to put it in service
the equipment has some chips which supplied by + or - 5 volts , + or - 3 volts but if the main power of the equipment is less than -38 volts the source of that chips will be not
+5,-5,-3,+3 volts which mean the function of the chips can''t work perfectly and the equipment can? reset it self and cause that problem.