CCE HPS-2185FS, Руководство по обслуживанию

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HPS-2185FS
3.6.2 Chrome sensibility
a) Adjust the TV to a “PP” condition.
b) Apply to the antenna input a 60dB
µ
V signal with 88% AM modulation with
PAL-M color pattern (frequency and channel factory defined), and FM sine
wave 400Hz audio modu-25 kHz deviation.
c) Observe the TV screen under test and reduce the output generator level
until the color pattern be visible. At this condition the output generator level
represents the sensibility of chrome in dB
µ
V.
Note: If the TV under test is two or three-system mode, repeat this procedures for
the PAL-N and NTSC-M signal system.
Condition Minimum Nominal Maximum Unit
PAL-M - 300,00 400,00
dB
µ
V
PAL-N - 300,00 400,00
dB
µ
V
NTSC-M - 300,00 400,00
dB
µ
V
3.6.3 AGC circuit
a) Apply to the antenna input a 60dB
µ
V signal with 88% AM modulation with
“WHITE” pattern (frequency and channel factory defined), and FM sine
wave 400 Hz audio modu-25 kHz deviation.
b) Adjust the TV to “PP” condition.
c) Read the DC voltage at the tuner AGC terminal. Utilize a DC electronic
voltmeter with minimum 10 M
Ω
impedance.
Condition Minimum Nominal Maximum Unit
Vcc = 5V -10% (1/2)Vcc +10% V
DC
3.6.4 AFT circuit
a) Apply to the antenna input a 60dB
µ
V signal with 88% AM modulation with
PAL-M COLOR BAR pattern (frequency and channel factory defined), and
FM sine wave 400 Hz audio modu-25 kHz deviation.
b) Connect a oscilloscope in the output video detector and read the peak to
peak burst level signal “Vb”.
c) Increment the generator frequency by 500 kHz and read the new value
peak to peak burst signal “Vh” and calculate the percentage as following:
E= V
H
/V
B
x100%
d) Decrement the generator frequency by 500 kHz and repeat the
procedure(c) reading the peak-to-peak burst signal V
L
and calculate the
percentage as following:
E= V
L
/V
B
x100%