PS Engineering PMA8000G System Installation And Operation Manual - page 11
PS Engineering
PMA8000G IntelliAudio Audio Selector Panel With flightmate®
Installation and Operator’s Manual
200-890-0912
Page 2-4
Rev. 7, July 2017
Some avionics do not provide a separate audio low, and may introduce additional electrical noise into the
system. For best results, connect the audio low from the audio panel to the radio ground, using one conduc-
tor of the twisted-shielded cable.
2.4.6.1
Speaker Load
The PMA8000G contains one speaker amplifier, and does not provide a speaker load for legacy units.
Some units with internal speaker amplifiers, such as the King Radio KX170-series, require a resistive load
to prevent damage if their speaker amplifier is not used. Connect the speaker output from the legacy radio
to an external speaker load of at least 16
, 3W.
2.4.7
Transmit Interlock
Some communications transceivers use a transmit-interlock system. To fully utilize the Split Mode feature,
this function must be disabled. Consult that manufacturer's installation manual.
2.4.8
Backlighting
Control of the GREEN and WHITE button text and backlight-
ing is through the aircraft avionics dimmer For 14 V aircraft,
connect J2 Pins 6 and 7 to the aircraft dimmer bus, and pin 5 to
ground. For 28-volt systems, connect pin 7 to the aircraft dim-
mer, and pins 5 and 6 to ground.
If an external dimmer control is not used, or the dimmer volt-
age is less than 0.5 VDC, the white text will be at full intensity.
There is a backlighting adjustment, see
§2.8
for information.
2.4.9
Unswitched inputs
J1, pins 31, 29 and J2 pin 15 are unswitched, unmuted (by transmitter keying), inputs # 1, 3 and 4, respec-
tively. These inputs are presented to the pilot and copilot regardless of the audio configuration, and will
always mute the entertainment inputs. These 510Ω inputs can be used for altimeter DH audio, GPS way-
point audio, autopilot disconnect tones, or any other critical audio signal. Unswitched #1 is always present-
ed to the speaker, plus to the crew headphones, and is available to the pilot in fail-safe (off) mode.
Unswitched 3 and 4 inputs are always presented to the crew headphones and over the aircraft speaker.
Unswitched
Input
Hear in
Fail Safe
Hear in
Crew Headset
SPR button
Select
Gain
1
Yes
Yes
No
1:1(fixed)
2
No
Yes
Yes
1:1(fixed)
3
No
Yes
No
Adjustable
4
No
Yes
No
1:1(fixed)
Table 2-2 Unswitched input table
Unswitched #2, J1 pin 44 is unswitched is always connected to the Pilot’s headphone. However, this
unswitched audio is only presented to the aircraft speaker when the SPR push button has been selected.
The audio low for unswitched #4 (J2, pin 15) should be connected to a convenient audio low. However, this
should NOT be connected to Music Low.
Unswitched #1 is presented to the pilot headphone in fail-safe (off) mode.
NOTE
Inputs 1, 2 and 4 are fixed (1:1), and any audio level adjustments must be made at the input source.
Unswitched #3 has a variable adjustment control located on the bottom side of the unit. This control allows
you to adjust the volume level of that unswitched input. Refer to Adjustments section.