Technics RS-676US

13
ITEM
MEASUREMENT & ADJUSTMENT
REMARKS
Erase Current
Equipments:
* VTVM
* Oscilloscope
* Resistor (1Q)
Balance
(for recording level)
Equipments :
* VTVM
* Oscilloscope
* AF Oscillator
* ATT
1. Connect 1Q resistor between ground side terminal of
erase head ground lead wire remove (See fig. 21).
2. Connect VTVM to both ends of 1Q resistor.
Erase Head
Fig. 20
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) = T (a)
Standard Value: 140+35mA
1. Test equipments connection is shown below.
LINE IN LINE OUT) -——~
(AF Oscillator) (ATT) (Record Mode) (VTVM) (Oscilloscope)
Fig. 22
. Place UNIT into record mode, and set the record level
control VR to minimum.
. Supply 1kHz signal (—7dB) from AF oscillator, through
ATT, to LINE IN (L-CH).
. Set the balance control VR to L-CH maximum.
. Adjust record level contro! VR so that the output level at
LINE OUT on VTVM becomes —7 cB.
. At this time, connect test equipment to R-CH, and supply
1 KHz (—7 dB) to LINE IN (R-CH) (record VR should not be
moved).
. Set the balance volume to R-CH maximum.
. Measure the output level at LINE OUT (R-CH).
. Adjust VR20 so that measured value at LINE OUT (R-CH)
becomes —7 dB (See adjustment parts location on page ~
19).
* Record Mode
Erase Head
* Record Mode