Sharp VC-A10 Service Manual page 30

VC-A10/A10S/A500
VC-A50/A50S/A50SB
VC-A60/A75/A80S
CHECKING OF PLAYBACK LEVEL
Measuring Oscilloscope
instrument
Mode Record/Playback
Cassette
Self-recorded tape
(See Note below 1)
1.0 ± 0.2 Vp-p
Specification
1. Be sure that E-E level has been correctly specificed.
2. Connect a 75 ohm terminating resistor to the VIDEO OUT
jack and connect an oscilloscope across this terminating
resistor.(See Note below 1 )
3. Play a self-recorded tape.
4. Make sure that the output signal amplitude is
1.0Vp-p as shown in Figure 5-4.
Note:
1 If the 75 ohm terminating resistor is missing, the signal
amplitude will be doubled.
2 Self-recorded tape is a tape which program was re-
corded by the unit being adjusted.
AUDIO CIRCUIT ADJUSTMENT
CHECKING OF E-E LEVEL
Measuring AC milli-voltmeter
instrument
Mode E-E/Record
Input signal
1kHz, –8.0 dBs (at RCA type jack)
Test point AUDIO OUT jack
–8.0 ± 3 dBs
Specification
1. Connect an AC milli-voltmeter to the AUDIO OUT jack.
2. Feed the audio signal shown in table to the AUDIO IN
jack.
3. Put the unit in E-E or recording mode.
4. Make sure that the output level is value shown in table.
1.0 Vp-p
Figure 5-4.
CHECKING OF AUDIO RECORD LEVEL
Measuring AC milli-voltmeter
instrument
Mode Record/playback
Input signal 1kHz, –8.0 dBs
Test point AUDIO OUT jack
–8.0 ± 3 dBs
Specification
1. Connect an AC milli-voltmeter to the AUDIO OUT jack.
2. Feed the audio signal shown in table to the AUDIO IN
jack.
3. Make the self-recording and playback of the signal.
4. Make sure that the output level is value shown in table.
CHECKING OF ERASE VOLTAGE AND OSCILLA-
TION FREQUENCY
Measuring Oscilloscope
instrument
Mode Record
Test point Full erase head
Control T601
70 ± 5kHz, 40Vp-p or greater
Specification
1. Connect an oscilloscope across the full erase head.
2. Put the unit in recording mode.
3. Make sure the erase voltage across the full erase head is
approx. 40Vp-p or more and frequency is 70 ± 5kHz.
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