Sharp VC-MH80

Hi-Fi -AUDIO CIRCUIT-ADJUSTMENT
IMPORTANT NOTES ON Hi-Fi SECTION
1. Though adjustment procedures are written for
the left channel, those for the right channel are
basically the same.
-Words shown in the bracket “[ I” are for the
right channel only.
2. SERVICING OF THE Hi-Fi block
1) “RECORD MODE”
Under this condition record a stereo broadcast
on tape and adjust control.
2) “PLAYBACK MODE”
Under this condition, play a-Hi-Fi tape and
adjust control.
(You can select the audio output channels in
the playback mode by pressing the MENU on
the remoto control or the SET UP button on
the’i/CR.
-Set the desired Audio output mode by
pressing the (+) or (-) button.
The Audio Output mode will change in the
normally select Hi-Fi L+ R mode with the
pressing the ( +) or (-) button both the L and
R audio channels are taken from the Hi-Fi
mode track. The L and R indicators light up on
the multi-function display in this mode.)
CHECKING OF E-E LEVEL
Measuring
instrument
AC milli-voltmeter
Mode
E-E or Recording mode
Input signal 1 kHz,
- 8dBs
Test point
AUDIO OUT jack
Specification
-8?2dBs
1. Feed the audio signal shown in table to the left
channel of the AUDIO IN jack.
2. Connect an AC milli-voltmeter to left channel of
the AUDIO OUT jack and right channel of the
AUDIO OUT jack.
3. Put the unit in E-E or recording mode with the
make sure that the milli-voltmeter reads
specified value.
(Check the level is less than 2dB both Left
channel and Right channels.)
VC-MH80
VC-MH90
ADJUSTMENT OF FM CARRIER FREQUENCY
Measuring
instrument
Frequency counter
Mode
Input signal
Test point
Controls
E-E or REC mode
Not required
TP6301 (Sig.) - TP6302 (GND)
R6310 [R6363] NTSC carrier
frequency control
R6308 [R63651 PAL carrier
frequency control
Specification
1.3 [ 1.7] MHz ? 5kHz (at NTSC
mode)
1.4 [1.8] MHz + 5kHz (at PAL
mode)-
1. Put the unit in A/V input mode. Do not feed any
signal to the VIDEO IN JACK.
(Disconnect any cable from video input
terminal.)
2. Put the unit in E-E or recording mode and
connect a frequency counter to test points
TP6301 (Sig.) and TP6302 (GND).
3. Put the unit in NTSC mode with the adjust R6310
jR63631 (NTSC carrier frequency control) so that
the counter reads specified value:
4. In the next place put the unit in PAL mode with
the adjust R6308 [R6365] (PAL carrier frequency
control) so that the counter reads specified
value.
ADJUSTMENT OF LINEAR AUDIO BIAS
CURRENT
Measuring
instrument
Oscilloscope
Mode
Record
Input signal
Test point
Not required
TP6303 (GND) - TP6304 (Sig.)
Control
R6343 Bias current control
Specification
2.5 + 0.1 mVrms
1. Connect the oscilloscope to test points TP6303
(GND) and TP6304 (Sig.).
(Use TP6304 for ground lead.)
2. Put the unit in recording mode with the adjust
R6343 so that the signal amplitude is 2.5mVrms.
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