Yamaha P-115B, Service Manual

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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