Yamaha P-115B Service Manual page 61

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