PXE7300 Series IFE System Installation and Operator’s Manual
The PXE7300 power supply is specifically designed to reduce conducted electrical noise on the aircraft power bus by at least 50dB. Although this is a large amount of attenuation, it may not eliminate all noise, particularly if the amplitude of noise is very high. There must be at least 12 VDC present at the connector pin 21, of the PXE7300 for the power supply to work in its designed regulation. Otherwise, it cannot ade- quately attenuate power line noise. Shielding can reduce or prevent radiated noise (i.e., beacon, electric gyros, switching power supplies, etc.) However, installation combinations can occur where interference is possible. The PXE7300 was designed in a RFI hardened chassis and has internal Electromagnetic Interfer- ence (EMI) filters on all inputs and outputs.
Ground loop noise occurs when there are two or more ground paths for the same signal (i.e., airframe and ground return wire). Large cyclic loads such as strobes, inverters, etc., can inject noise signals onto the airframe that are detected by the audio system. Follow the wiring diagram very carefully to help ensure a minimum of ground loop potential. Use only Mil Spec shielded wires (MIL-C-275000, or better).
The PXE7300-Series units are compatible with both 14 and 28 Volt DC systems. A two (2) Amp PULL-TYPE breaker is required. Power and ground wires must be a twisted #18 AWG pair. Connect airframe power ground to Pin 22 only.
See Appendix B for typical circuit breaker layout.
Figure 2-4 Circuit breaker location (Typical) The PXE7300 has an automatic dimming of the pushbutton annunciator LEDs controlled by a photocell. A dimmer control allows the bezel text backlighting to be controlled by the aircraft dimmer. Connect the 14 V dimmer control to pin 1, the 28 V dimmer to pin A, as required.
The passive AM/FM antenna, part number 510-730-0001 (included) is optimized for FM radio perform- ance. Therefore, when used for AM reception, the operator may only receive the most powerful 3 to 5 AM stations. In contrast to an ADF, where audio fidelity is not important, the PXE7300 requires higher signal levels to ensure fidelity.
For optimum performance, some installers may desire an external AM/FM antenna. PS Engineering rec- ommends a Comant CI-222-L, installed in accordance with AC43.13-1A, Chapter 3.
Another AM performance-enhancing alternative is to connect the PXE7300 antenna input to an unused VOR port of the VHF NAV antenna splitter. Do NOT add another splitter.
The included antenna can be mounted wherever convenient inside the cockpit, as long as it is in a window. Verify that the antenna is not an impediment to crew vision outside the cockpit when installed,
For optimal operation, it should be near the windshield. Clean the mounting surface with appropriate