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ELECTRICAL
SECTION
4, VCO Adjusteent
1) Connect a frequency counter to TP] (IC2 pin Gon
PRE
AMP C.8.)
via an
oscilloscope,
2) Connect
TP2 (1C2 pin®@ to ground and adjust
L4 so that
the frequency counter reads 8:35+0,01MHz.
3) After adjustment is completed, disconnect IP2 from
ground,
Osci Ioscope
Frequency
counter
Monitor
output
§. Recording Current Adjustment
Adjustment points : SFR] and SFR2
Do not perform this adjustment.
6. TACH Adjustsent
Conditions : + Alignment tape: TY-7251
"Test points: TP3(RF),TP4(SbH),7P5(SWH.RF),
TP6(GND)
+ Adjustment point: SFR i ([A] MAIN C.B.)
+ Settings of oscilloscope: V axis (0.lv/div.)
T axis (2~5msec)
External trigger
* Setting of test mode: Test mode 2
(Test tape mode)
See TEST MODE.
1) Connect an oscilloscope to test points TP3 (RF) and TP4
(SWH).
2) Connect TP5 (SWH, RF) to TP6& (GND).
3) Play the alignement tape and adjsutment SFR1 so that
the period is 800+10us at TP3.
4) After adjustment is completed,
turn the Power switch off.
(The test mode is released).
5) Disconnect TP5 from TP6.
T+ O90 ZF '0 (pees?
7. ENV Adjustment
Conditions : + Alignment tape: TY-7551
+ Test points: TP4(S¥H}, TP7(ENV)
+ Adjustment
point:
SFR2
+ Settings of oscilloscope: V axis (0.1V/div.)
T axis (2~5msec)
External
trigger
1) Connect an oscilloscope to TP7 (ENV) and TP4 (SWH).
2) Play the first track on the alignment tape and adjust
SFRZ so that the voltage at TP7 is 600mV.
If values VA and VB are different, adjust to the higher
voltage.
(Caution)
If the RF waveform is as shown in the figure below,
perform tape path adjustment again.
{NG)
. ATF Adjustaent
Conditions :+ Alignment tape: TY-7111
+ Test points:
TP4(S¥H),
TP8(PILOT)
+ Adjustment point: SFR3
= Settings of oscilloscope:
V axis (50mV/div.)
T axis (2~5msec)
External trigger
1) Connect an oscilloscope to TP8 (PILOT) and TP4 (SWH).
2) Play the alignment tape and adjust SFR3 so that the
voltage at TP&8 is 200mV.
If values VA and VB are differenct, adjust to the center
value (VC) between then.
VC : 200nV
. Error Rate Adjustment
Conditions : + Alignwent tape: TY-7551
+ Test points: TP9(IC1 pin ({8) FLAG)
TP10(IC1 pin (9)c2)
+ Adjustment points: SFR5, SFR6
1) Connect CH-1 of the oscilloscope to TPS.
2) Connect CH-2 of the oscilloscope to IP10.
3) Trigger the oscilloscope with CH-2.
4) Adjust SFR5 to decrease the flags at TP9 (ICI pin
FLAG).
5) Adjust SFR6 to further decrease the flags in the Cl
correction section.
—
6) Perform steps 4) and 5)a fev times to minimize the
flags.
Error rate adjustment wavefora
TRANSISTOR
ILLUSTRATION
28A1314
ac®
28C2712
2S8B1182
28C4116
2804213
RN2301
DTA114
DTC144
Pe
ee
el
c2
101 Pin @)
C1
Pin@®
;
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i
i)
exc ———Illtit +
t
|
PCH data
,
POM data |
Sub-code
C1 correction C2 correction
C1 correction
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