Sharp VC-MH75HM

29
VC-MH75HM
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:
1If the 75 ohm terminating resistor is missing, the signal
amplitude will be doubled.
2Self-recorded tape is a tape which program was re-
corded by the unit being adjusted.
1.0 Vp-p
Figure 5-4.
CHECKING OF PLAYBACK LEVEL
Measuring Oscilloscope
instrument
Mode Record/Playback
Cassette Self-recorded tape
(See Note below 2)
Specification 1.0±0.2Vp-p
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.
AUDIO CIRCUIT ADJUSTMENT
CHECKING OF E-E LEVEL
Measuring AC milli-voltmeter
instrument
Mode E-E/Record
Input signal 1kHz, –3.8 dBs
Test point AUDIO OUT jack
Specification –3.8 ± 2dBs
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 AUDIO RECORD LEVEL
Measuring AC milli-voltmeter
instrument
Mode Record/playback
Input signal 1kHz, –8.0 dBs
Test point AUDIO OUT jack
Specification –8.0 ± 3dBs
CHECKING OF ERASE VOLTAGE AND OS-
CILLATION FREQUENCY
Measuring Oscilloscope
instrument
Mode Record
Test point Full erase head
Control T601
Specification 70 ± 5kHz, 40Vp-p or greater