Yamaha P-45B - Page 61

61
P-115B/P-115WH/P-45B
P-45B
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 Pilot lamp with Power SW ON --> Check items q to r sequentially.
2) No sound or distorted sound --> Check items q, t, y and OUTPUT check items.
Test■Point
NO. Test Point Circuit Judgment criteria Measured by Parts with possible defects
①
+12V Power supplay for DM circuit board More than 12.0V Multimeter
FT101, D101 or FZ101
(On JK circuit board)
②
+HP
Power supplay for Headphone
circuit
More than 10.9V Multimeter TR102
③
+3.3D 3.3 V power for digital circuit 3.3V±0.1V Multimeter IC101
④
/RESET CPU & memory reset signal 3.3V±0.3V Multimeter IC106
⑤
DAC-L DAC output L channel
There shall be audio
output without distortion.
Signal Checker IC301
⑥
DAC-R DAC output R channel
There shall be audio
output without distortion.
Signal Checker IC301
Note1: Use the standard AC adapter PA-150B or PA-150U for check operation.
Output
NO.
SPEAKER
OUTPUT
PHONES
OUTPUT
DAC-L/R
TEST POINT
Parts with possible defects
1
× × ×
IC100 or Error Detect Circuit
2
○ × ×
IC301 or Error Detect Circuit
3
× ○ ○
IC302, HP JACK
or Error Detect Circuit
4
○ × ○
IC303
Note: “
○
” mark expresses normalcy and “
×
” mark expresses a failed state.
DM■Circuit■Board■(ZN840900)
Component side