Adjustment (Electrical); Reference Voltage And Waveform At Each Ic Pin - Technics SL-1200MK2 Service Manual

ADJUSTMENT (Electrical)
Adjustments (Electrical)
Notes: 9 Make the following adjustments after replacing parts such as IC's, transistors, diodes, etc.
Condition of the set .
1 . Power switch . . . . . . . . . . . . . ON
2. Pitch control . . . . . . . . . . . . . Center position
3.
Speed selector switch . . . . . . . 33-1/3 r.p .m .
Instruments to be used
1 . Tester
2. Frequency counter
REFERENCE VOLTAGE AND WAVEFORM AT EACH IC
PIN
IC101 (AN6675)
SL-1200MK2 SL-12
Q2
C
(D
O
OO
Adjustment Connection Points Adjustment Point
Adjustment Method
Adjustment
of pitch
Frequency counter 1 . Pitch control switch to center position .
A
control t0%
(2) -. TP27 VR301 2. Adjust VR301 for 262.08 kHz 10 .05 kHz of
(PITCH)
0 - GROUND frequency.
Adjustment Tester
B of pitch
TP31 and VR302
Adjust VR302 for 2.7 k92 t0.1 of resistance
control gain TP32
value
Braking
Adjust VR201 for complete stop within 120
°
- 270°
C adjustment - VR201 after stop signal initiated . (Turntable becomes free a
(BRAKE) few seconds after stop)
STOP SIGNAL
2700
&1
Turntable
0
Start
Stop
Start Stop Start Stop
2V 2V ( 04""W
© 2V
2V,~,
, .. ©
=
15V
1""
~3
0v
ov
®
Same as at right
,uV
O
sv
sV
q
Os
sV
sv
0
©
15V
15V
20V 20V ao .6
©
5V ( 'S 6 .6V
S
~
T
20V 20V
10 .1
OO
oV
ov ©
15V
15V
(S
,
f
©
20V 20V o .l,
08
5V 5V
-0
0
209. ,
®
0 .2v 0.2V , t
15v '
T
©
1 .7V 1 .7V
r
ov ov
*40
"1
,.,_
© 15V
15V
©
15V
15V