Sylvania 6842PF M Service Manual page 36

FLOW CHART NO. 3
Audio is not outputted from audio output terminal normally.
Input audio signal.
Is audio signal inputted to each pins on IC4301
and IC4302 ?
[****] is the check point on the component side.
When inputting to Video 1 jack...
IC4302 Pin (13) [J165] AUDIO1(L)
IC4301 Pin (13) [J135] AUDIO1(R)
When inputting to Video 2 jack...
IC4302 Pin (14) [J166] AUDIO2(L)
IC4301 Pin (14) [J129] AUDIO2(R)
When inputting to component 1 jack...
IC4302 Pin (15) [CN4711 Pin (1)] AUDIO3(L)
IC4301 Pin (15) [CN4711 Pin (2)] AUDIO3(R)
When inputting to component 2 jack...
IC4302 Pin (12) [CN4711 Pin (4)] AUDIO4(L)
IC4301 Pin (12) [CN4711 Pin (5)] AUDIO4(R)
Is input switching signal inputted to each pins on
IC4301 and IC4302?
[****] is the check point on the component side.
Pin (11)
[CN4711, 3pin]
Video 1
L
Video 2
L
Component 1
H
Component 2
H
Is audio signal outputted to each pins on
IC4301 and IC4302?
[****] is the check point on the component side.
IC 4302 Pin (3) [J148] L-CH
IC 4301 Pin (3) [J142] R-CH
Is audio signal outputted to the IC4802,1pin
(L-CH) and the IC4802,7pin (R-CH)?
Is the "L" pulse supplied to the base of Q4711
and the base of Q4712?
Check lines between IC4802 and JK4703 and
service it if defective.
Yes
Pin (10) Pin (9)
[CN4711, 2pin] [CN4711, 1pin]
L L
L H
L L
L H
Yes
Yes
Yes
Yes
Check lines between Pin (13) on IC4302 and
No
JK4702, between Pin (13) on IC4301 and
JK4702, and service it if defective.
No
Check lines between Pin (14) on IC4302 and
JK4402, between Pin (14) on IC4301 and JK4403
and service it if defective.
No
Replace the Digital CBA.
No
Replace the Digital CBA.
Check lines between each pins on IC4302 and
each pins on CN4711, between each pins on
IC4301 and each pins on CN4711 and service it if
No
Pin (9) on IC4301,IC4302
Pin (10) on IC4301,IC4302
Pin (11) on IC4301,IC4302
Check +5 V line and service it if defective.
No
Is +5V signal inputted to Pin (16) on IC 4301
No
and Pin (16) on IC 4302 ?
Yes
Replace IC4301 or IC4302.
No
Check IC4802 and the periphery circuit, and
service it if defective.
No
Is the "L" pulse supplied to the base of Q4709,Q4710?
Check Q4709,Q4710 and the
periphery circuit, and service it
if defective.
1-8-5
Pin (1) on CN4711
Pin (2) on CN4711
Pin (3) on CN4711
Yes
Replace
the Digital CBA.
L0653TR
No