SERVICE MANUAL
Document No
Date of Origin
Date of REV
51-L-DSR004
98-10-21
PAGE REV.
0
PAGE
41 /102
S-00-005(96.03.27)
REV.1
7-11-2.
Check G729_INT
(U305.21
or R361) with an oscilloscope
after typing
¡°
T5
¡±
command.
If there is an outcoming
signal check U305.36
and 38
pins for open/short
circuits
and if it is O.K replace
R6715(U305).
But if there is no outcoming
signals,
check the incoming
signals
of
U305 and the control
signals
as below;
(First type
¡°
T5
¡±
command
then check)
7-11-2-1.
/G729-cs
(U305.11)
7-11-2-2.
/MEMRD (U305.12
or R355)
7-11-2-3.
/MEMBE0
(305.8 or R357)
7-11-2-4.
Address
lines (R346,R348,R350
~ R352)
7-11-2-5.
Data lines (R337 ~ R344)
7-11-2-6.
/RESET (U305.23
or R301)
If the above signal lines are O.K. replace
U305 IC and if the signals
are not
normal then check U1(TP2).
7-11-3.
As the next sections
are mostly analogue,
correct
the errors by
tracing
the signals
as below;
7-11-3-1.
Check U752.15
and U752.4 with an oscilloscope.
7-11-3-2.
Then U701.1 and U701.7
7-11-3-3.
Then U901.26(TP944)
and U901.28(TP946)
Correct
the defects
if there is no signals
at the above items and if it is
O.K. but no signal then check the scart connectors
or the cables.
7-12.
BEEP
7-12-1.
Type "T1" command
then check U900 pin 3 and 7.
If there is no signal then go to 7-12-2.
If there is a
signal then go to 7-12-3.
7-12-2.
Check the incoming
signals
of U900 pin 2 and 6, if it is O.K. then
replace
U900(1406HA).
If there is no incoming
signals
check R956,
R955,R954
with an oscilloscope.
If there is no signals
on above resisters
then check TP2(U1).