⑤
⑦
⑨
④
①
②
③
⑥ ⑧
DGND
LDGND
AGND
■
DM CIRCUIT BOARD CHECK METHOD
The DM Circuit Board is provided with test points for service check purposes.
Check the test points on the DM Circuit Board if the following symptoms appear.
Symptoms and check items
1. No LCD display with Power SW ON
--> Check
items
①
to
④
and
⑦
sequentially.
2. No sound or distorted sound
--> Check
items
⑤
,
⑥
,
⑧
and
⑨
sequentially.
DM Circuit Board (ZA675600)
TEST POINT
NO.
Test Point
Circuit ID
Circuit
Judgment criteria
Mesured GND
Measured by
Parts with
possible defect
①
TL505
+5D
5V power for
digital circuit
5.0V ±0.5V
DGND
(TL509)
Multimeter
IC502
②
TL506
+5LED
5V power for
LED drive circuit
5.0V ±0.5V
LDGND
(TL510)
Multimeter
IC502
③
TL507
+3.3D
3.3V power for
digital circuit
3.3V ±0.3V
DGND
(TL509)
Multimeter
IC504
④
TL102
+1.2D
1.2V power for
digital circuit
1.2V ±0.2V
DGND
(TL509)
Multimeter
IC104
⑤
TL504
+9A
9V power for
analog circuit
9.0V ±1.0V
AGND
(TL508)
Multimeter
IC503
⑥
TL319
+5A
5V power for
analog circuit
5.0V ±0.5V
AGND
(TL508)
Multimeter
IC312
⑦
TL101
/RESET
CPU & memory
reset signal
3.3V ±0.3V
DGND
(TL509)
Multimeter
IC102 or IC103
⑧
TL324-TL325
DACL OUT
DAC Output
L channel
There shall be audio output
without distortion.
–
Signal Checker
IC101 or IC310
⑨
TL326-TL327
DACR OUT
DAC Output
R channel
There shall be audio output
without distortion.
–
Signal Checker
IC101 or IC310
58
MX61/MX49
