As for “Description of APSS”, “Mechanical Adjustment”,
A
S
for all the items except “VU-Meter Adjustment”, refer to
“General Alignment Instruction” and
“Electrical Measure- Service Manual of Model GF-9191X.
ment”, refer to Service Manual of Model GF-9191 X.
LEVEL AND SENSITIVITY ADJUSTMENT OF VU METER
1. Connect the V.T.V.M. across the
100
ohm resistors
(RI
15,
R116).
2. Short circuit the primary coil of the oscillation coil
(L301
)
to stop bias oscillation.
3. Connect the signal generator to the EXT. MIC jacks
(JlOl
A,
JlOlB)
and apply signal
(IkHz,
-6OdB) to the unit.
4. Place the unit in RECORD mode.
5. Connect DC voltmeter between TP51 and TP52 (ground)
and adjust left channel record level control
(R148)
so that
DC voltmeter indicates I
.OV.
6. Adjust the semi-variable resistor
(R907)
so that 5th LED
7. Next, change the voltage of TP51 to 0.95V by sliding the
record level control (R148), and in this time, check the 5th
LED
(D914)
of VU meter fails to light.
8. Adjust the record level controls (R147,
R148)
so that the
V.T.V.M. reads 3.5mV.
9. Adjust the semi-variable resistors (R 187,
R188)
so that 4th
LEDs
(D908,
D913)
of VU meters begin to light.
IO.
Set the level of signal generator to
-6ldB
and this time,
check the 4th
LEDs
(D908,
D913)
of VU meters fail to
light.
(D914)
of VU meter begins to light.
SWITCH
POSITION
lower
(SW1
01
F)
tape
node
(SW107)
stereo
neter/light
(SWlO9)
VU
nixing
(SW104)
off
oudness
(SW1
08)
off
:ape
(SW106)
normal
-ecord
mode
(SWIOS)
manual
SIGNAL
GENARATOR
R/P HEAD
MIC
JACK RECORD mode
DC VOLTME
TEF
TP52
Figure 6
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