Service Adjustments - Sanyo C20LB87B Service Manual

Service Adjustments

Following adjustments are not required to readjust when replacing the memory IC.
FOCUS ADJUSTMENT
(1) Receive the monochrome circular pattern.
(2) Set the brightness to normal and contrast to maximum.
(3) Adjust the focus control on the F.B.T. for the best focus on the
screen centre.
HORIZ. WIDTH AND HIGH VOLTAGE CHECK
(1) Receive the monochrome circular pattern.
(2) Set the brightness and contrast to maximum.
(3) If the picture is too wide, or narrow, cut or short the "AJ1" on
the main unit. When AJ1 is shorted, the horizontal width
increase. When AJ1 is cut, the horizontal width decrease.
Important note: When AJ1 is cut, in order to prevent a spark,
leave the opening between cutting portions
5mm or more.
AJ1
more than 5mm
(4) Connect a high voltage probe to anode lead of the picture
tube.
(5) The high voltage must be 25KV ± 1KV and less than 27.5KV
at 0 beam current (Brightness and contrast
minimum setting).
Note: If the picture tube is replaced, check the high voltage. The
horiz. width adjustment affects the high voltage.
Therefore, re-check the high voltage.
+B POWER SUPPLY ADJUSTMENT
(1) Connect DC meter to "TP-B" (R638) and the ground. Set the
+B adjustment control (VR631) to mid-range.
(2) Set the brightness to normal and contrast to maximum. Tune
the receiver to an active channel and synchronized picture.
(3) Adjust +B adjustment control (VR631) for 130 ± 1,0 volt DC.
MAIN BOARD
C
B
F.B.T.
T401
F.B.T.
FOCUS VR
(Upper side)
FOCUS ADJUSTMENT
-13-
+B POWER SUPPLY ADJUSTMENT
VR631
Q613
POWER OUT
T611
CONVERTER
E
TRANS.
Q432
HORIZ. OUT
C
AJ1
HORIZONTAL WIDTH
ADJUSTMENT
TP-B
B
E
T431
H-DRIVE
TRANS.