Nagra NAGRA 4.2 Instruction Manual - page 23
Synchronizing a Recorded Tape
Check that the machine is fitted with the QSLI synchronizer circuit. This circuit is located on the right side of the
battery compartment inside the machine. The circuit faces downwards, and has its front right corner cut away.
Feed pilot input connector (44) with the reference signal either from the pilot out socket on the ATN–3 (for syn-
chronization to mains) or from the machine to which the 4.2 is to be synchronized. Turn the main function selec-
tor to the "PLAYBACK WITH LOUDSPEAKER" position, and after a short period (typically 1 1/2 secs) pilot indi-
cator 15) should once again show a white segment. Check the level of the pilot signal from the tape by switch-
ing modulometer switch (12) to the position "PILOT PLAYBACK". The needle should deflect about half way. If
the modulometer selector is switched to the position "SYNCH" the meter will indicate the deviation between the
external pilot reference and the pilot signal from the tape.
Frequency Meter (optional accessory QFM)
This device measures the frequency of the pilot signal. If the meter switch is in the PILOT FREQUENCY posi-
tion, the meter will indicate the frequency. The scale is from +4% on the left side to –4% on the right. The accu-
racy is about ±O.1% on the centre of the scale. In addition, the frequency meter circuit gives a warning if the
frequency is more than 5% out from its nominal value. It this is the case, the rotary "Pilot" indicator turns black.
The QFM exists in two versions for 50 Hz and 60 Hz (QFM 50 and QFM 60).
Quartz Crystal Pilot Generator (optional accessory QGX–3)
This accessory is designed for synchronous filming without cable between the camera and the Nagra. It supplies
a signal whose frequency is 50 Hz ± 0.001%, and is very stable within a wide temperature range.
A dummy plug is supplied with the generator. The solution of using a dummy piug rather than a switch, has been
adopted in order to reduce the risk of human error. The QGX–3 is switchable and gives a 50 Hz or 60 Hz signal.
Pilot Indicator
This device is found on the upper right of the front panel. It shows a white cross when the Nagra is in operation
and it a pilot signal of sufficient amplitude is provided, and if there is no "Alarm" signal in the pilot system. The
"Alarm" signal will appear and turn the indicator black if the following conditions occur:
a)
if the frequency of the pilot signal is incorrect (on condition that the QFM frequency meter cir-
cuit is installed)
b) if the pilot signal does not reach the pilot head (on condition that the QSLI synchronizer circuit
is installed)
This is indicated in the position "TEST" of the main function selector. When the Nagra is in playback, this indi-
cator will only show a white segment when a pilot signal is being played back from the tape and another pilot
signal is being fed from outside. It one of these two signals is missing, the indicator will remain back. This is
very important when using the QSLI.
Internal Synchronizer (optional accessory QSLI)
This device has two functions:
a) It measures the amplitude of the playback pilot signal on the tape. With the meter switch in the
position "PILOT PLAYBACK" the meter indicates the amplitude. The normal value should be
between 1 and 2 V on the lower middle scale.