Yamaha P-105B - DM Circuit Board Check Method; DM Board Symptoms and Voltage Checks; DM Circuit Board Output Checks

P-105B/P-105WH
■ 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 light with Power SW ON
--
> Check items
①
to
⑥
sequentially
2. No sound or distorted sound
--
> Check items
①
,
⑥
and
⑦
, and OUTPUT check items.
OUTPUT
Note: Use the standard AC adapter PA-150A or PA-150U for check operation.
Note: “O” mark expresses normalcy and “X” mark expresses a failed state.
DM Circuit Board (WZ891700)
TEST POINT
NO. SPEAKER OUTPUT
PHONES/
OUTPUT
AUX OUT
DAC-L/R
TEST POINT
Parts with Possible Defects
1XXXX IC1
2 X X X O IC1 or Error Detect circuit drive
3 O X X X IC23
4 X O O O IC1, IC22 or HP JACK
5 O X O O IC33
6 O O X O IC32
NO. Test Point Circuit Judgment Criteria Measured by Parts with Possible Defects
①
+B Power supply for More than 10.0V Multimeter TR2 or D18
DM Circuit Board (On PNJK Circuit Board)
②
+5V 5V power for 5.0V ±0.2V Multimeter IC24
digital circuit
③
+3.3V 3.3V power for 3.3V ±0.1V Multimeter IC21
digital circuit
④
+1.2V 1.2V power for 1.2V ±0.1V Multimeter IC20
digital circuit
⑤
RES CPU and Memory 3.3V ±0.3V Multimeter IC4
reset signal
⑥
DAC-L DAC output
There shall be audio output Signal checker IC23
L channel
without distortion
⑦
DAC-R DAC output There shall be audio output Signal checker IC23
R channel
without distortion
①
②
③
④
⑤
⑥
⑦
P-105B/P-105WH/P-35B/L-85WH/LP-5AWH
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