4.7 Driver Switch Logic Circuit Board, continued
Also present on the Driver Switch Logic board are power supply diagnostic LEDs and various
circuit test points.
Several green LEDs give a visual indication that the power supplies are functioning. The LEDs
do not indicate that the voltage is correct for its given power supply, they are just merely an
indication that voltage is present. LED DS7 is the indicator for the +5 volt power supply, DS5
is the indicator for the +12 volt power supply and DS6 is for the –12 volt power supply.
Test points that are present on the board can be used to measure various power supply and
circuit voltages . See illustration 4-6 for test point descriptions and typical voltages.
The voltages listed in the chart are approximate values. The colors in the left hand column in-
dicate the color of the test point on the circuit board.
The audio filter output test point voltage should be 0 volts during an audio fault such as during
silence or a loss of program audio. This voltage will be constantly changing while program au-
dio is present. This circuit is only active if the /Auto Carrier line has been pulled low by
grounding pin 5 on the Remote I/O connector on the back of the transmitter.
See illustration 4-7 for diagnostic LED and test point positions on the Driver Switch Logic
board.
4-12 FM600 User’s Manual
Illustration 4–6 Driver Switch Logic Board Test Points
Test Point Description Voltage
TP1 -12V DC supply -11.76v to -12.24v
TP2 +12V DC supply 11.76v to 12.24v
TP3 +24V Driver supply (switched) 23.52v to 24.48v
TP4 +24V DC supply 23.52v to 24.48v
TP5 Ground 0v
TP6 +5V DC supply 4.9v to 5.1v
TP7 PA1 Drain current/10 .100v = 10 amps
TP8 PA2 Drain current/10 .100v = 10 amps
TP9 ALC Control voltage 0v to 6v
TP10 Ground 0v
TP11 Audio filter output **See text below
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