GE OPTIMA MR360 Service Training page 144

• PS for Mega SW & RRX provides three kinds of input voltage to Regulator Box through the
filters in the System Cabinet Interface Board(SCIF). But the cables from the SCIF
connectors to Regulator Box are very long, which will surely cause voltage drop on the
cables. The input voltage of Regulator Box must be within the required range with the
voltage drop. So the system uses two exactly identical cables and connectors to decrease
the voltage drop. The output power cables from Regulator Box to Mega SW are also two
exactly identical cables.
• Current SV system doesn't have the individual 12V Power Supply, which is for future use
to support MNS. That is why 3 out of 4 input LEDs and 5 out of 6 output LEDs are lit in the
Regulator Box.
• There are five voltage regulators to transform three kinds of input voltage to five kinds of
output voltage. Voltage Regulator Board monitors all regulated voltages using
comparator chips and sends status information (Power Good) to Mega Switch. Only when
all five regulator outputs are normal, then Power Good signal is Ok, which is a DC signal
ranged in 2.2 to 3.3V at pin 19 of J2.
• In the Mega Switch, the regulator just transforms the 6.85V input voltage to other three
kinds of output voltage. Mega SW also monitors the output voltage and send status
information, and this status information and Power Good signal will be sent to a logic
AND gate to get the Mega SW Power Good signal. Only when output of Voltage Regulator
Box and Regulator in Mega SW are both normal, the Mega SW Power Good signal is OK.
But this signal is not sent to RRX in SV system.
• Other input voltages to Mega SW except 6.85V just go through the Mega SW and are
directly sent to RRX.
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