Boeing 737-300 Maintenance Manual

Page 7 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 (b) The desired ATC system is set with the transponder select switch. The '1' position causes the Control Panel to send an 'ON' discrete to transponder No. 1 if the AIR/GND RELAY is in AIR mode and the mode switch is set to XPDR. The '2' position causes the Control Panel to send an 'ON' discrete to transponder No. 2 if the AIR/GND RELAY is in AIR mode and the mode sw ...

Page 104 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 Prepare the ATC system for troubleshooting as described in paragraph 3. On the transponder’s front panel push and hold the TEST switch. Do ALL the LED indicators come on for 1 second? NO Replace the ATC transponder (Ref 34-53-21/401) and do the required test. YES If the R/T light indicator comes on, replace the ATC transponder (Ref 34-53-21/401) and do the requi ...

Page 102 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 Prepare the ATC system for troubleshooting as described in paragraph 3. On the transponder’s front panel push and hold the TEST switch. Do ALL the LED indicators come on for 1 second? NO Replace the ATC transponder (Ref 34-53-21/401) and do the required test. YES If the red TPR-FAIL LED indicator comes on, replace the ATC transponder (Ref 34-53-21/401) and do th ...

Page 4 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 airplane carrying the transponder. The coding of a mode A reply can consist of up to fifteen pulses. Twelve of these pulses carry the identification number. Two others, called framing pulses, come before and after the twelve information pulses. The last is a special identification pulse to aid the radar operator. The mode C reply is basically the same as a mode A rep ...

Page 7 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 (b) The desired ATC system is set with the transponder select switch. The '1' position causes the Control Panel to send an 'ON' discrete to transponder No. 1 if the AIR/GND RELAY is in AIR mode and the mode switch is set to XPDR. The '2' position causes the Control Panel to send an 'ON' discrete to transponder No. 2 if the AIR/GND RELAY is in AIR mode and the mode sw ...

Page 6 Use and disclosure shall be in accordance with the proprietary legend located on the cover of this document AUG 15/10 B. Functional Description (1) Receiver (a) Received signals from the antenna are routed through the Diplexer/Low Pass Filter and applied to the Pre-selector/Mixer. In the Pre-selector the signal is passed through a bandpass filter tuned to 1030 MHz. The filter output is applied to the mixer diode and mixed with the 970-MHz local oscillator (LO) signal. The LO signal ...