Technics RS-273US - Page 8

ITEM
MEASUREMENT & ADJUSTMENT
REMARKS
Erase Current
Equipment:
* VTVM
* Oscilloscope
* Resistor (1Q)
Overall Gain
Equipment:
* AF Oscillator
* VTVM
* ATT
* Oscilloscope
* Test Tape
(Reference Blank Tape)
...C-RF (for CrO2)
...C-RA (for Normal)
1. Connect 1Q resistor between ground side terminal of
erase head and ground lead wire removed.
2. Connect VTVM to both ends of 1Q resistor.
Erase Head
(VTVM) (Oscilloscope)
Fig. 16
3. Place unit into record mode, and measure voltage across
the 1Q resistor.
4. Determine erase current with the following formula.
Voltage across both ends of 1(Q)
Erase current (A) = TO)
Standard Value: 130+20mA
* Record Mode
Erase Head
Ne
1. Test equipment connection is shown below.
(Test Tape) (Playback Mode) (VIVM (Oscilloscope)
Fig. 18
2. Set tape selector to CrO2 position.
3. Supply 1 kHz signal (—24 dB) from AF oscillator, through
ATT, to LINE IN.
4. Adjust ATT until monitor level at LINE OUT becomes 0.5 V
(—6 dB).
5. Using test tape C-RF, make recording.
6. Playback recorded tape, and make sure the value at LINE
OUT jack on VTVM becomes 0.5 V.
7. \f measured value is not 0.5V, adjust VR7 (L-CH), VR8
(R-CH).
8. Repeat from step (5).
9. For normal tape, tape selector to normal position, change
test tape to C-RA, and take the same step as for CrOz, but
to adjust, use VR1101 (L-CH), and VR1102 (R-CH).
* Record/Playback Mode
* Record Level Control
MAX
* Standard Input Level:
MIC......... —70+30B
LINE IN ...~24+3 dB
* Adjustment procedure
should be: CrOz->Normal
* Location of VR7, VR8,
VR1101 and VR1102 are
shown in fig. 26.