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PIF/AFT/AGC ADJUSTMENT
PIF/AFT/AGC~
i./i!IlI_
3. AFT ADJUSTMENT: TP204(T104}
1.
Receive the E-12CH (PAL colour bar) signal. if this
signal is not available, any signal above the E-5CH
band is acceptable.
-Field strength:
55-80
dB~N
Make sure the frequency is almost the same as
that of the received channel (± 3011Hz).
2. Using the channel setting control, make a frequency
of 224.25 MHz appear on the screen. (AFT
011)(11
any other channel than E-12CH is received, make
its frequency on the screen.)
3. Turn T204 (T104) coil clockwise first to have 6V
reading and then counterclockwise to get 0.2 V
reading.
Within this range, adjust this coil to reach the volt-
age below.
4. Adjust T204 (T104) so that the DC voltage at the
AFT OUTterminal - pin (1) of IC201 (IC101) be 3.3
±
0.1 V. (See
Fig. 3.)
DC voltage at TP201
6V
3.3V
DOWN A
S'
S
Ill"
C
UP
Fig. 3.
• Turn the core counterclockwise for the UP di-
rection, and clockwise for the DOWN direc-
tion. Adjust the T204 core to point B (between
B' and B"). Point A and C are rejectable.
3.l3iYJt'i.tiJiiJAFTB-'JiJiiJJM:T204(T104)
1.1ti/l(E-12~iJ:t(PALttJ:itlGi~){s-l9'.
7GE-12
~.m4.Al!t.
~Jll~5~.~~~
• •
{s-'%1't'l:l'.
itl;iUj1illt:
55-80dB~V
Milj.iEW!J:iI!!iJlijl'ilii/l(~iJ:ti¥J.$(
± 30kHz).
2.iilii±!IJ!iJ:tNlE**.
iJlijj)t3H~7i't±li¥J!IJ!$
~
-m:
~
224. 25MHz. (AFT
~
'1" *
~
tt
~).
(lti/l(
~ 7E-12~
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i¥J!Wl iJ:t fa%l!t. !IZ.
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Eq;ii;;m$:i¥J.$).
3
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Jtl..EEj;6V,
i9!atHjJrli:JME~atB-'JWMiJtl..EEj;
o. 2vj;iltrm,
iJiiJi'JT204~gj3 ,~~gj3
<=P
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B-'JJtl..EEmJ<S~""f~[',~*o
4.iJiiJi'JT204(T104),~IC201(IC10l)51~(1)
(AFT~t!:l!ljjij )B-'JH.l:IiEJtl..EE-mJ<S~3.
3V±O.1Va<J
m.JE~*o
TP201Ji"JJ[tm.rtffi
6V
3.3V
H$ A
B'
B
B"
C n$
003
*
litH,'
j;~8tH:1ji!;J8t~ ~f$,
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H
.<:.
is]
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(A,
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5. VIDEO DETECTION LEVEL ADJUSTMENT: R224
1. Receive the "B/G SYSTEM PAL COLOUR BAR" signal (100% white colour bar). Ste the S system to B/G.
2. Adjust R224 so that the video output at the AV OUT terminal be 1.0
±
0.05 Vp-p with a 75-ohm termination.
4. RF AGC CUT-IN ADJUSTMENT: R226 (R116)
P201
(P101)
rtt!ll.ti1.
004
+
J
I 0
+
-wlBin
7i'1l!i:U
t..
9 ..
1
Y
4.
M~13 iYJ:tt\'~~*1JRF AGC1lIlAB-'JiJiiJ~
:R22B(R116)
1.~41l:E-12~j1[ "PAL*U~*3~" 1~%o
itl;iUj1illlt: 57±
IdB~ V(~1t75'PIHIl.)
2. l1H!l4fj1f 7i'
j!:,jt
It 7i'
lI!i: H
'1" P201.
it -wlBifl :
~6.
5V
3.
ME~R226
(R116),
~FJrl!.Qtl<i!.EEil~:j(J3~Jll*o
4.
;f§&jJrli:Jm:f§!j:i!?ME~R226
(R116) ,.j4<i!.EEil
;tiJiiJ~Jll*m-o .1VZ~j,J3!:o
5.
iJlij1El-'%51illlt~63-67dB ~
V.
W!Jl.\.7G~j'll'
t±l
m.
6.
NiJIij{"a--,%j1illlt~90-95dB ~
v.
W!Jl.\.7G~llt
fill-l9'iJlijttJitHst±lm.
i'E1i :
:llcjiIHI1!Jll::r-*50/75~!l.tltfH~fli¥J500
~~l;iU51illlttt. ~J;ib51illlt!f<:·~~~55
±
IdB
~
V.
~~~. iI1!Jll~~fll!t.
B:;lfJ:!R
E!3
~~fl'fjH~i¥J~.Il.!Jtm;1<;.
5.1'Ji!.~~~Jtl.~B-'JiJiiJ~:R224
l.lii/l(
"B/Gfi1IJ:itPAL~~"
{i1!%(lOO%s'@.fl1f%). tll:S-fillJ:it'fB/G{12I.
2. iJIij l'iR224. iI1!j' l l'
~ ~
t±llt/HI: i¥J
t!lI.!IJ!~
t±lj1illltii;J£l. 0 ± O. 05Vp-pi¥J m lE
j!:,jt
('1"750 Ii
~~).
i'E1i:
Jll
"IfillJ:itPALlGi~"
1EI%*i£ffJltJ3lliJlijJMl!t. B:tll:StlJ:it'fI{;LI.
P201
TV
set
Fig. 4.
Oscilloscope
~
1. Receive the.E-12CH "PAL COLOUR BAR" signal.
-
Fieid strength: 57
±
1
dB~V
(75 ohms open)
2. Connect the oscilloscope to P201, as shown in
Fig. 4.
-
Bias box:
About 6.5V
3. Turn R226 (R116) to have the highest voltage.
4. Turn R226 (R116) slowly in the oppsite direction
untill the voltage goes down 0.1 V below the high-
est level.
5. Adjust the signal level to 63-67
dB~V
and make sure
there are no noise.
6. Now adjust the signal level to 90-95
dB~V
and make
sure there is no chrominance modulation beat.
Note: If a 50 ohm field strength meter is used without a
50/75 impedance converter, set the field strength
to 55
±
1
dB~V.
Pay attention to a loss that would
be cause with the converter.
....
W
NN
(Q(Q
JJJJ
~~
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