Sharp RT-203H - Circuit Adjustment; Bias Oscillator Frequency and Bias Current; Erase Current Adjustment; Playback Sensitivity Adjustment

RT-203H(S)
©
Connect the input/output plug to the receiver, or apply
+12.8V by an external DC power supply.
SETTING
POSITION
OF SWITCH
AND KNOB
Doiby NR Switch: off
Deck 1 Tape Selector Switch: Normal
Deck 2 Tape Selector Switch: Normal
Input Selector Switch: Line Beat Cancel Switch: A
OSCILLATOR
(INPUT
FREQUENCY
BIAS
CURRENT
ERASE
CURRENT
DECK 1
PLAYBACK
SENSITIVITY
ADJUST-
MENT
POINT
REMARKS (CHECK)
105 + 5 kHz
L: VR301 | Normal: 45mV
R: VR302
(Metal: 36 + 4V)
Normal: 550mV
See that the electronic
voltmeter reading is
within the range from
490mV to 620mV
If not, take the
procedures shown in
the Table *1.
BIAS
L: VR102
R: VR202
Test tape
MTT-150
Test tape
MTT-150
SENSITIVITY
DECK 2
RECORD/
PLAYBACK
SENSITIVITY
Non-
recorded
tape
(MTT-502)
400 Hz
—13 dB
(1V =0dB)
. Adjust the record level
knobs so that the elec-
L: VR103
R: VR203
2.
Table * 1
tronic voltmeter reads
Voltmeter reads
360mvV.
More than 620mV Cut the resistor R113, R213
Cut the resistor R111, R211
tape recorded and ad-
just the semi-variable
resistor so that the
electronic volt-meter
read 360mV.
Playback the normal
Less than 490mV
CIRCUIT ADJUSTMENT
R101 or R201
Record Mode Record/Playback Etectronic
Head Voltmeter
Frequency Counter
Figure 12—1 BIAS OSCILLATOR FREQUENCY/BIAS
CURRENT
Record Mode TP301 Erase Electronic
Na Head Voltmeter
Ground
Figure 12—2 ERASE CURRENT
* Electronic
CNP8 Voltmeter
@ or @)Pin
Playback Mode
Test Tape
MTT-150
Ground
Figure 12—3 DECK 1/DECK 2 PLAYBACK SENSITIVITY
CNP8
Low Frequency ®or Pin
Oscillator Attenuator Record Mode
Non-recorded
Tape
MTT-502
CNP8
Electronic @)or@Pin
Playback Mode
Figure 12—4 DECK 2 RECORD/PLAYBACK SENSITIVITY
MAIN PW.B.
VR401 VR404
MOM
VR402 Vv
a403 R403
Figure 12—5 ADJUSTMENT POINTS
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