Read Sharp VC-MH815 (serv.man9) Service Manual online
30
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
1. Be sure that E-E level has been correctly specificed.
2. Connect a 75 ohm terminating resistor to the VIDEO
2. Connect a 75 ohm terminating resistor to the VIDEO
OUT jack and connect an oscilloscope across this
terminating resistor.(See Note below 1)
terminating resistor.(See Note below 1)
3. Play a self-recorded tape.
4. Make sure that the output signal amplitude is 1.0Vp-p
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.
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
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.
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
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
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.
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
CILLATION FREQUENCY
Measuring
Oscilloscope
instrument
Mode
Record
Test point
Full erase head
Control
T601
Specification
70
±
5kHz, 40Vp-p or greater
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