PS Engineering PM2CREW - Manual (Page 5)

PS Engineering
PM2Crew Expansion module (11918)
200-004-0004 Page 2-2 Rev. 4, Sept. 2000
For panel mounted installation
1. Using the template, drill four holes in the instrument panel in a location convenient to the pilot or
passengers position(s).
2. Insert the PM2CREW from behind the instrument panel, aligning the holes for the knobs.
3. Place the aluminum faceplate over the knob shafts and secure, using the two # 4-40 round head screws
provided.
4. Apply the PM2Crew label to the panel, using care to align the holes over the knob shafts.
5. Install the knobs over the volume and squelch control shafts.
Blind mounting:
1. Install the unit in a convenient bulkhead, as above. Add the aluminum doubler if the panel is less than
0.040” thick.
2. Remote mount the squelch control in a location convenient to the passengers.
3. If desired, the volume can be adjusted at installation, there are two holes in the side of the unit, one for
left, and another for right channel.
4. If desired, a remote switch (not included) can be installed to override the SoftMute function. This
should be located convenient to the passengers.
Remote Squelch Mounting:
0.472
Ш0.323 Ш0.118
Remote Squelch Mounting Holes
(Pot 675-020-0103)
Not to scale. Dimensions in inches,
2.4 Cable harness wiring
To complete the installation, a wire harness must be made as shown in Appendix D. PS Engineering can
make a custom-tailored wiring harness for the installer. All harnesses use Mil-spec quality components
with professional techniques, and are fully tested before shipment. Contact PS Engineering for more
information. The PM2Crew connects to the main unit through a 4- or 5-conductor, shielded cable.
2.4.1 Electrical Noise Issues
WARNING: You must use separate shielded cables for the microphone and headphone jacks. Combining
these two wires WILL cause loud oscillations and degrade the intercom function. The oscillation is caused
by the cross-coupling between the large headphone signal and the small microphone signal. The resulting
feedback is a high-pitched squeal that varies with the volume controls.
Shielding can protect the system from radiated noise (rotating beacon, power supplies, etc.). However,
installation combinations occur where minor interference is possible. The PM2CREW was designed in an
interference -protected chassis and has internal filter capacitors on all input lines.