Sigtronics US-DR - Manual (Page 7)

OK, skip to the “PTT Test” on page 7. Otherwise, if something
is not working right, see the following troubleshooting guide
to find and fix the problem before going on with the instal-
lation:
NO INTERCOM IN ANY OF THE HEADSETS:
1. Make sure the UltraSound VOLUME and SQUELCH con-
trols are set to full clockwise position.
2. Make sure the vehicle power is on.
3. Check the in-line fuse in the UltraSound Headset Jack and
PTT switch Cable.
4. Check the power connection – red wire.
5. Check the ground connection – green wire.
6. Check for a short or open on the headphone wire (Blue
wire on the Headset Jack and PTT Switch Cable). The problem
could be anywhere along the blue wire connection between
the headset jacks and the UltraSound unit.
INTERCOM IN SOME HEADSETS BUT NOT IN OTHERS:
1. Make sure that UltraSound controls are set as above.
2. Make sure that none of the PTT buttons are pressed.
3. Make sure that none of the PTT wires (white/red, white/
blue, or yellow if applicable) are shorted to ground.
4. Check specific “bad” headset jack wiring for:
a) Microphone wire (jack ring terminal) open or shorted
to ground.
b) Headphone wire (jack tip wire) open or shorted to
ground.
c) Incorrect wiring - wires switched either at the jack or
at the point where the hookup wire connects to the
Headset Jack and PTT Switch Cable.
LOUD SQUEAL IN THE HEADSETS ALL THE TIME:
1. First make sure all headset plugs are plugged in all the way
and that no part of any headset jack is physically touching
any metal.
2. Check headset jack wiring at all jacks. For example, incor-
rect wiring such as reversing the jack tip and ring wires will
cause a squeal.
3. Check for open headset jack barrel connection (black wire).
The open could be anywhere along the black wire connec-
tion between the jack and the UltraSound unit.
4. Check for a microphone line (white/black, white/orange,
tan or white/brown wires) shorted to the headphone line
(blue wire). The short could be at one of the headset jacks
or in the wiring between the unit and a jack.
Note that for 2 and 3 above, it will only squeal if a headset
is actually plugged into the specific jack that is wired incor-
rectly.
PTT Test:
If all above is good, make sure all headsets are plugged into
their respective jacks. Put on the Driver’s headset and posi-
tion the microphone as usual. Press the Driver’s PTT switch.
While continuing to hold down the switch, talk into the mic
and verify that you can still hear yourself. Also, while holding
down the PTT switch, verify that none of the other headset
microphones are active. Release the PTT switch.
Now put on the Officer’s headset, position the microphone,
and press the Officer’s PTT switch. Verify that only the Officer’s
headset microphone is active as his switch is held down.
If the system has a jack and PTT wired up at the vehicles pump
panel, unplug the headset from the Drivers position and plug
it into the pump panels jack. Press and hold down the pump
panel PTT switch. Verify that only the pump panel headset
microphone is active.
If all works fine, skip down to “Electrical Noise Test” on this
page. If anything does not work as above, you have one of
three possible PTT switch wiring errors:
1. PTT line (white/red, white/blue or yellow wires) open or
not connected between a PTT switch and the UltraSound
unit.
2. Open or missing return line (black wire) to a PTT switch.
3. Reversed PTT lines. The Drivers PTT line connected to the
Officer’s PTT switch and visa versa.
Electrical Noise Test:
The last thing to do before the radios are hooked up to the
unit is a simple noise test to verify system wiring as well as
vehicle electrical system integrity.
1. Unplug all intercom headsets except for the Drivers.
2. Make sure all the UltraSound panel controls and switches
are set as in “System Setup” on page 6.
3. Start the vehicles engine and let it idle a bit. This is a
stationary test — the vehicle should not be moving and
should be in “PARK” or “NEUTRAL” with brakes set.
4. Close all vehicle windows and doors to eliminate as much
background noise as possible.
5. Turn on as much vehicle electrical equipment as possible.
This usually means all lights and strobes. Do not turn on
sirens or horns.
6. Put on the Driver’s headset, position the mic, and make
sure the headset volume control is set to maximum.
7. With the vehicle still in “PARK” or “NEUTRAL” and brakes set,
slowly increase the vehicle engine rpm from idle to about
1500 RPM and back again. While doing this, listen for any
whine or hum in the headsets. Except for some possible
engine background noise being picked up from the head-
set microphone you should not hear any “Electrical” whine
or hum in the headset.
8. Shut off the vehicle engine as well as the lights, strobes,
etc. If, while the engine was running, there was no electrical
noise, skip down to “Radio Hook Up” on page 8. If you did
hear electrical noise, use the following to track down the
problem:
Turn the vehicle power off and disconnect the UltraSound
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