Agc Adjustment - Hitachi CMT2195 Service Manual

CMT2195 |
P. i. F. CARRIER FILTER ADJUSTMENT
ADJUSTMENT LOCATION L202
-CMT2195
AGC ADJUSTMENT
ADJUSTMENT LOCATION VR202
Preparations for adjustment Adjustment Proced ks/Wavef orm
Apply the following signal across IF|(1)| AdJ ar aetna — i: ee eval ate oe ania oe
y g ehOSs Jus BOE OR. PARE BLEND a uF 1 |With the signal received, apply heat| 1 |Received following channel and streng~
run for more than two minutes to avoid th.
the influence of circuit tempereture
drift.
charge" is seen on voltmeter.
Then adjust L202 to obtain reading on
voltmeter as below,
out and GND of tuner.
CHANNEL : CCIR 5
STRENGTH : -49dBm
~~ VIDEO SIGNAL
GENERATOR
FP SIGNAL
GENERATOR
2|Connect the voltmeter of at least
100kQ internal impedance to the AGC
terminal of the tuner.
4,3+0, 2V
Adjust VR202 until the following
voltage is reached.
V1—(0, 50. 2y)
2} Vi:ithe voltage without signal
SIGNAL LEVEL : -10~0dBm
SIGNAL : PHILIPS PATERN F acorae "raat
1.
Connect the oscilloscope to the pin @ b
of 1C201.
Supply OC voltage as below.
Delay time: More than 0. lsec,
HORIZONTAL CENTER POSITION ADJUSTMENT
ADJUSTMENT LOCATION V¥R701
Preparations for adjustment Adjustment Procedure Remar ks
+B ADJUSMENT
1 |Receive the circle pattern signal,
1 | Turn VR701 (H, Phase) and adjust so that| Picture information amount
size scales on the left and right are| The amount of information means the amount
ADJUSTMENT LOCATION R963 (VR 951) 2|Set the brightness and contrast VRs to! equal. (Refer to Fig. 3-2-1.) of the transmitted picture that can be
ry max imum, displayed on the CPT screen. It is nece-
Preparation for adjustment Adjustment Proced ae ssary to increase this amount of
sa pera ae em information as much is possible and also
AC input voltage 220 + 5V/50HZ. Adjust R963 (VR 951) to obtain decrease the lack of raster as far as
+B voltage as below. 1 3 ft possible.
Turns on the set and set the +B voltage = 95 + 0,3V
brightness and contrast to max.
(SIGNAL: PHILIPS PATTERN)
within 1.5~2 (recommended scale)
After 30 sec heat-run, check &
Size scale
adjust the +B voltage.
Rea Di p o s e t
my 9 ae