Tait T860 Series II, Service Manual

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B3.6 T865 Initial Tuning & Adjustment
M860-00-Preliminary
30/06/98 Copyright TEL
Continually decrease the RF level to maintain 12dB sinad.
Readjust L410, L420, L460 & L470 to give best sinad.
With PL210 and PL220 connected for de-emphasised audio response, the receiver
sensitivity should be better than -117dBm, assuming that the audio levels are not
being overdriven (refer to Section 3.4.5).
3.4.4 Mute Adjustment
Carry out the one of the following sets of instructions according to the mute option you
have selected.
3.4.4.1 Noise Mute
Connect pins 1 & 2 of PL250 to enable the noise mute.
Set the RF level to -105dBm with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz.
Set RV230 (front panel gating sensitivity) fully anticlockwise.
Adjust RV330 (noise mute gain) to close the mute (if necessary turn off the RF sig-
nal and then turn it on again).
Rotate RV330 anticlockwise until the mute just opens.
Adjust RV230 for the required opening sinad.
3.4.4.2 Carrier Level Mute
Connect pins 2 & 3 of PL250 to enable the carrier mute and disable the noise mute.
Apply an on-channel signal from the RF generator at the required mute opening
level with 3kHz deviation (2.4kHz) [1.5kHz] at 1kHz.
Adjust RV235 (carrier mute) to close the mute (if necessary, momentarily turn off
the RF), then slowly adjust it until the mute just opens. The mute should now
open at this preset level.
3.4.5 Line Amplifier Output
Apply an on-channel signal from the RF generator at a level of -70dBm with 3kHz
deviation (2.4kHz) [1.5kHz] at 1kHz.
Adjust RV210 (front panel line level) to set the line level to the required output
level.