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3-9
FA - SERVICING
SERVICING
IF AND AUDIO SERVICING
AGC DELAY
With a strong noise-free antenna signal, adjust with left
select key the RF AGC (#20) to a lower setting until the
signal gets noiser. Increase the setting again (with right
select key) for a noise-free picture.
AUDIO LEVEL ADJUSTMENT
a) Apply a RF signal with good video and audio at
100Hz at 100% modulation.
b) Access item #19 AUDIO LEVEL on the service menu.
c) Place a high impedance meter on pin #19 of IC1400
or the positive side of capacitor C1427. Adjust with
left/right select keys the AUDIO LEVEL register to 250
mVrms.
MTS DECODER ALIGNMENT.
The purpose of this procedure is adjusting registers of
SONY audio decoder and sound processor CXA2054S
(IC1400).
Initial conditions:
a) Alignment should be accomplished at least ten min-
utes after the TV set have been turned on.
b) TV sound must be set for flat response (EZ sound in
Normal).
c) Audio mode must be set for Stereo.
d) Use 8 ohm resistive loads instead of the speakers.
e) Open RM1416 and RM1417 in order to disconnect
the RF audio signal.
f) Connect a Multiplex Modulator to negative of capaci
tor C1427.
Five register of the audio processor should be adjusted.
Bits TEST-DA and TEST1 should be set according with
the current adjust.
Inside of the service menu:
·To see TEST-DA and TEST1 registers enter the “B” key of
the remote control (TESTDA= “0” and TEST1 = “0” are
conditions for normal operation), then ten bits regis
ters will display in the bottom of the screen, upper of
tree rows (see the figure 1). The first one is TESTDA
register and the second one is TEST1 register.
·To change the state of TESTDA and TEST1 push the
“QUIT” key of the remote control.
ATT ADJUSTMENT
a) Set the chassis for RF input.
b) Set bits TEST-DA = “0” and TEST1 = “0”.
c) Input a 100 Hz signal at 25 KHz deviation (100 %
mod.), 75 us off to pin 19 of IC1400.
d) Adjust with right/left select keys the A ATT register
(item #30) for 490 mVrms (± 10 mVrms) in TVOUT-L
output, pin 44 of IC1400.
STEREO, SAP VCO ADJUSTMENT
a) Set bits TEST-DA = “1” and TEST1 = “0”.
b) Monitor the TVOUT-R output frequency (pin 43 of
IC1400) in a no input state.
c) Adjust with right/left select keys the A VCO register
(item #31) of IC1400 so that frequency is as close to
62.936 KHz (± 0.5 KHz) as possible.
STEREO, SAP DBX FILTER ADJUSTMENT
a) Set bits TEST-DA = “0” and TEST1 = “1”.
b) Input 9.4 KHz, 600mVrms to COMP-IN pin 19 of
IC1400.
c) While monitoring the STATUS FLAG (FILADJ bit, see
figure 2) of IC1400, adjust with right/left select keys
the A FILTER register (item #32). Align with the cen
ter of the FILADJ = 1 (Adjustment OK) condition range
(see figure 2).
FILADJ
FLAG
Figure 2 A FILTER adjustment.
0
0
1
ADJUSTMENT POINT
FILTER
REGISTER
63
SEPARATION ADJUSTMENT
a) Set bits TEST-DA = “0” and TEST1 = “0”.
b) Set volume at maximum.
c) Set a stereo signal, 300 Hz at 12.9 KHz deviation (30
% mod.), left channel only, dbx ON at pin 19 of IC1400.
d) Adjust with right/left select keys the WBAND register
(item#34) to reduce right speaker output at the mini
mum.
e) Set the frequency only of SIF signal to 3 KHz.
f) Adjust with right/left select keys the SPECTRAL regis
ter (item #35) to reduce right speaker output at the
minimum.
Содержание RP-29FA40-M
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