M850-00
T855 Functional Testing
B4.3
Copyright TEL 31/09/98
4.1 Current Consumption
Connect the T855 to a 13.8V power supply.
Rotate RV230 (front panel gating sensitivity) anticlockwise until the "Gate" LED is
extinguished.
Set switch SW201 (front panel monitor mute) to the
on
position.
Check that the current in the 13.8V power cable is less than 350mA.
Rotate the RV230 clockwise until the "Gate" LED is lit.
Rotate RV210 (front panel line level) and RV205 (front panel monitor volume) to
give maximum outputs.
Check that the current is less than 750mA.
Reset the front panel controls to the required settings.
4.2 Sensitivity
If CTCSS is enabled, disable the CTCSS tone by either programming the T855 for
"No Tone" on the set channel, or by pulling pin 10 of D-range 2 (CTCSS ENABLE)
low.
Apply an on-channel signal from the RF generator with ±3kHz deviation
(±2.4kHz) [±1.5kHz] at 1kHz.
Adjust the RF level to give 12dB audio sinad.
Check that the sensitivity is -117dBm or better.
4.3 Switching Range
Apply an on-channel signal from the RF generator at various frequencies within
the 5MHz switching range (front end bandwidth), corresponding to pre-pro-
grammed channels.
Measure the sensitivity at each frequency as described in Section 4.2.
Ensure that the sensitivity is -115dBm or better across the whole switching range.
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