SRK Electronics FMA501, Manual, Page: 11 / 33

SRK Electronics FMA501 manual
 2007 SRK Electronics Pty Ltd 10
there are no alarms and the unit has not been put into standby mode previously, the fans
should start.
4.4
Initial setup
Assuming that the amplifier has been correctly installed, enough RF input power should be
applied to give the desired forward output power. Initially set the drive power to zero and
slowly increase until the forward power, as shown on the LCD, is at the required level. Note
that it is not advisable to generate powers in excess of 500W.
4.5
Measuring other parameters
Once the correct forward power has been established, the other amplifier parameters may be
checked. The available parameters are as follows and can be accessed in turn by rotating
the control knob clockwise to go down the list, or anticlockwise to go up the list:
“Fwd Pwr” Forward RF output power in watts
“Ref Pwr” Reflected RF output power in watts
“”I/P Pwr” Input RF power in watts
“A Temp” Amplifier A temperature in °C
“”Amp A I” Amplifier A DC current in amps
“B Temp” Amplifier B temperature in °C
“Amp B I” Amplifier B DC current in amps
“Amp Volt” Amplifier DC voltage in volts
“AC Volts” Input line voltage in volts
Data and time, British 24 hour format
“Elapsed” Total number of days running
Selecting any of these parameters has no effect on the operation of the amplifier
4.6
Setting power supply voltage.
When running at output powers of less than 300W, improved efficiency and lower device
dissipation can be achieved by reducing the amplifier DC supply voltage to lower than the
nominal 50V. This PSU cut function can be performed via the front panel by selecting the
“Amp Volt” parameter and then momentarily pressing the control knob inwards. It will be
noticed that the indicated voltage will drop to a nominal value of 35V. Pressing the button
again will return the voltage to 50V.
If desired, the PSU voltage in the cut state can be adjusted using VR16 on the control board.
For security, the ability to select/deselect this function using the front panel can be disabled
using the FD command via remote control.
4.7
Setting the date and time.
The current date and time can be set by selecting date and time using the control knob.
Pressing the knob momentarily will make the years value flash. Whilst it is flashing, rotate the
knob until the current year is displayed. Press the knob momentarily and the month will now
start flashing. Set as per years and continue through day, hours, minutes and finally seconds.
When done, press the knob again and the flashing will stop. The date and time have now
been set.
For security, the ability to select/deselect this function using the front panel can be disabled
using the FD command via remote control.