Adjusting The Head Azimuth; Adjusting The Bias Current; Measuring The Signal-To-Noise Ratio (In Playback Mode); Measuring The Playback Frequency Response - Marantz SUPERSCOPE CRS-2104 Manual

6.2 ADJUSTING THE HEAD AZIMUTH
Playback
Mode
EXT SP 42
Jack
6.3 ADJUSTING TIE BIAS CURRENT
Set the power voltage to 9 V and set the TAPE SELEC-
TOR switch to NORMAL. Set the recorder in the record-
ing mode. Adjust the semifixed resistors R512 and R612
until the voltages across R519 and R619 are 5.3 mV.
The bias current will increase by turning the semifixed
resistors R512 and R612 counter-clockwise as locking
toward part arrangement.
CRS-2104
6.4 MEASURING THE SIGNAL-TO-NOISE RATIO
(IN PLAYBACK MODE)
Play the 333 Hz level adjusting tape MTT 112 back. Let
this signal level at the terminal J701 or J801 be a stand-
ard. In turn, play a unrecorded tape back and read the
noise output level.
VTVM
333 H
Tape e Playback
Mode
Unrecorded
Tape Playback
Mode
6.5 MEASURING THE PLAYBACK FREQUENCY
RESPONSE
Play the frequency response test tape MTT 216 back.
Read the signal levels at the terminal J701 or J801 at
various frequencies in reference to the 315 Hz level.
Frequency VTVM
Response
Tape Playback
Mode
6.6 MEASURING THE COMBINED RECORDING
AND PLAYBACK FREQUENCY RESPONSE
Connect a 1 kHz, —90 dBV signal from an audio-fre-
quency oscillator to the external mic jack and record it.
Similarly, record a 80 Hz, 125 Hz, 6 kHz, and 8 kHz sig-
nals. In turn, play the recorded signals back. Read the
signal levels at the terminal J701 or J801 in reference to
1 kHz, 0 GB signal.
AF
Oscillator
J701, J801
J701, J801
J701, J801
1 kHz, —90 dBV
; Unrecorded
if Recording Tape
/ Mode
Recorded
Portion Playback
ic
J701, J801