Revox C270 Time Code Bedienungsanleitung Seite 16

RAIOX
Bias level setting with VR5 *
7.
Set VR5 to its midway postion.
* Since this setting has very little effect on performance, VR5 will be replaced in the future by a
resistor of 50k.
Output level adjustment
8.
Insert the generated time code signal into the 0270 time code input. Measure the level of the
output signal on the 0270 TC (TC record = READY).Adjust with VR3 to a reading of +4 dBu, the
GOOD CODE LED [2] must be activated.
Record level adjustment
9.
Use the playback alignment tape 320 nWb/m 1 kHz in playmode. Measure at TPIO the level of
the signal. The meter should read -13 dBu +/- 3 dB. Use the measured value as reference for the
following adjustments.
Make a recording on a previously erased tape of approx. 15 seconds of time code signal. Rewind
a)
the tape and play the recorded part. Adjust with VR2 the output level to read the same value as
noted before as reference. Repeat the alignment until the reference value corresponds exactly to
the playback level.
Limiter operation check with TP7
10.
Make a comparison test between the TC test-tape and a TC recording made on the tape recor-
der. Compare the output-signal on TP7 with help of an oscilloscope (see diagram). Both signals
should reproduce a voltage of approx. 20Vpp and display a similar form. Without TC signal, the
signal to noise ratio measured on TP7 must be lower than 1Vpp.
11. Operating control
Record on a previously erased tape approx. 2 minutes of a time code signal. Rewind the recor-
ding, start the unit in its play mode. The GOOD CODE LED should constantly be lit up during the
2 minutes and not be interrupted when using the VARISPEED. If the signal cannot be read
correctly (GOOD CODE LED [2] flashes), repeat the corresponding alignment instructions.
12. Offset check
Connect the TC generator/reader onto the 0270 TC time code input as well as to the audio input
1 (in CALIBRATED mode). Reproduce the TC alignment tape by 15 IPS on the part where all the
channels have a time code recording. Display on the time code generator/reader the difference
between the two TC input signals, the tolerances should be as follows:
O ms +/- 2 ms @ 15 IPS playback head
O 2 ms @ 15 IPS SYNC
Switch the taperecorder to 7.5 IPS
O ms +1-2 ms @ 7.5 IPS playback head
O ms +/- 4 ms @ 7.5 IPS SYNC
If before-mentioned values cannot be achieved, mechanical realignment of the TC head (gap
positioning) will bring an improvement.
C270 TC
with VR3
VR2 and TPIO
head
head
12