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TCL-THOMSON Electronics R&D Center (Shen'Zhen Lab)
Ⅱ. Alignment contents：
1. Adjustment of B+ voltage
Receive Philips standard testing pattern to RF input.
If the VR800 exists in the board, adjust it in STANDARD mode until voltage at following
value：
Model
M123SP
21E10
2. RF AGC adjustment
AGC Alignment Procedures:
Apply 8-scale gray signal (80dB), then adjust AGC data in D-mode to get the noise
1)
picture ( snow picture) disappear exactly. Test Pin 1 of TU101 (IF output) and
record the voltage value as V1
<Illustrate as Picture A>
2) Apply 8-scale gray signal (80dB), and then adjust AGC data in D-mode until the
synchronization signal distortion appear exactly. Test Pin 1 of TU101 (IF output)
and record the voltage value as V2
3) Calculate the value of V
Apply 8-scale gray signal (80dB), test Pin 1 of TU101 (IF output), adjust AGC data
until the voltage of Pin 1 of TU101 V
4) Test three units according to 1)，2)，3) steps, and record the values of AGC in three
units. Take the average value as benchmark.
Remarks:
Comparing test is necessary due to different probe of Oscilloscope and different Test
Circuit (Picture A).
1)
AGC voltage value should be tested afresh, due to the type/supplier of Tuner
or Saw filter changed, or other related components changed.
3P f
input
M123SP 南美软件
Chassis Name
2006-04-29
Issued on
2006-07-29
Updated on
B+ (v)
110±2.0
110±2.0
P-P.
<Illustrate as Picture A>
P-P.
with the formula: V
P-P
P-P
＝(V2
P-P
P-P
IN60
IN60
100K
(Picture A)
Serial No.
Page
Version
12
1/2
×V1
)
＝(V2
P-P
P-P
1/2
×V1
)
。
P-P
output
6 of 13
2.0
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