Panasonic National RS-460S Service Manual page 3

ADJUSTMENTS
MEASUREMENT AND ADJUSTMENT METHODS
A. PRESSURE ROLLER ADJUSTMENT (See fig. 5)
1. Set into playback mode.
2. Connect the tension gauge to pressure roller lever and pull it in the direction of the arrow as shown in fig. 5.
3. Measure the tension at the moment when the pressure roller moves away from the capstan.
Standard tension: 390-£60 gr
4. |f the tension is out of tolerance, bend the part (a) of the pressure roller spring in either direction shown by
the arrow until the correct pressure is attained.
B. RECORDING BIAS CURRENT ADJUSTMENT (See fig. 6)
1. Connect 10Q resistor as shown in fig. 6.
2. Connect VTVM to both ends of 10Q resistor.
3. Set into RECORD mode, read voltage on VT VM.
Standard voltage: 5.0+0.5 mV.
4. If the voltage is out of tolerance, adjust control VR203 (L-CH) and VR303 (R-CH) (shown in adjustment parts
location on page 6) until the VTVM indicates 5.0+0.5 mV.
| Tension gauge
ea gaug
'
Record mode
GZ
<A
"Pressure roller spring
Fig. 5 Fig. 6
C. OTHER SPECIFICATIONS FOR REFERENCE (NON ADJUSTABLE)
ITEM VALUE REMARKS
Takeup tension. 55+15 gr-cm Use cassette torque meter (SRK-CT or RP-8063).
Tension of detect piece. 50+10 gr —
Wow & flutter. RMS: 0.4% or less Use 3 kHz test tape (C-WAT).
Tape speed fluctuation. +1.5% Use 3 kHz test tape (C-WAT).
To obtain 0.7 V of headphone output level.
Bias oscillation frequency. 29+5 kHz
Erase current. DC: 9+1.5mA