Sanyo 28H1 Service Manual page 12

SERVICE ADJUSTMENTS-2
Please refer to the "Component Locations" for the adjustments and test points.
VCO ADJUSTMENT
1. Receive the circular pattern.
2. Adjust the picture to obtain the best picture by using
T103.
B1 POWER SUPPLY ADJUSTMENT
1. Set VR641 to be mechanical centre before pressing
the main switch.
2. Receive the circular pattern.
3. Set brightness and contrast controls to normal.
4. Connect digital V-meter to "TP453" on the sub/def.
board.
5. Adjust voltage to be 137±0.5V
the sub/def. board.
AFT ADJUSTMENT
1. Receive the clearest station.
2. Adjust AFT to obtain the best picture by using T102.
AGC ADJUSTMENT
NOTE: Do not attempt this adjustment with weak
signal.
1. Receive the clearest station.
2. Set AGC VR(VR101) in direction which causes snow
noise to appear, then in the opposite direction until
snow noise just disappears.
FM DETECTOR ADJUSTMENT(UK/Ireland only)
1. Receive the monaural station of system I.
2. Connect voltmetre between TPC and TPE.
3. Adjust the voltage to be 6.0±0.2V
PILOT ADJUSTMENT(Europe only)
1. Receive the A2 stereo signal
Carrier :5.5MHz + 5.74MHz
Deviation :27kHz
2. Connect oscilloscope between TP34A(pin 5 of IC3401)
and TP34E.
3. Adjust the amplitude to be maximum by using T3401.
by using VR641 on
DC
by using T101.
DC
VIDEO AMPLITUDE ADJUSTMENT(Europe only)
1. Receive the PAL colour bar pattern.
2. Connect oscilloscope between JT1201(+) and
JT1201E(-) on the back board.
3. Adjust the video amplitude to be 1.0Vp-p±0.05V by
using VR1201 on the back board.
100% white level
DOUBLE SCAN ADJUSTMENT
Receive the PAL colour bar pattern. Adjustment points
are on the double scan board.
[PLL ADJUSTMENT]
1. Connect oscilloscope between C7226-(TPOSC)(+)
and GND(-).
2. Adjust voltage to be 2.5V
DC=0
[CLAMP ADJUSTMENT]
1. Connect voltmetre between pin 52 of IC7201(+) and
pin 48 of IC7201(-).
2. Adjust voltage to be 2.0V
[OUTPUT LEVEL ADJUSTMENT-Y]
1. Connect oscilloscope between pin 6 of K73C(+) and
GND(-).
2. Adjust the Y signal amplitude to be 0.7Vp-p by using
VR7351.
-12-
1.0Vp-p
by using T7201.
DC
2.5V
DC
by using VR7201.
DC
0.7Vp-p
Service Manual EH1 chassis