Yamaha P-115B Service Manual page 60

P-115B/P-115WH/P-45B
■ ■ 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 Pilot lamp with Power SW ON --> Check items q to t sequentially.
2) No sound or distorted sound --> Check items q, y, u and OUTPUT check items.
Test■Point
NO. Test Point
① +B
② +5V
③ +3.3V
+1.2V
④
⑤ RES
⑥ DAC-L
⑦ 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
○
5 ○
Note: " " mark expresses normalcy and "
○
DM■Circuit■Board■(ZN321200)
60
Circuit
Power supplay for DM circuit board
5 V power for digital circuit
3.3 V power for digital circuit
1.2 V power for digital circuit
CPU & memory reset signal
DAC output L channel
DAC output R channel
AUX-OUT
OUTPUT
× ×
× ×
○ ○
× ○
○ ×
" mark expresses a failed state.
×
P-115B/P-115WH
Judgment criteria Measured by
More than 10.0V
5.0V±0.2V
3.3V±0.1V
1.2V±0.1V
3.3V±0.3V
There shall be audio
Signal Checker
output without distortion.
There shall be audio
Signal Checker
output without distortion.
DAC-L/R
Parts with possible defects
TEST POINT
× IC1 or Error Detect Circuit
× IC23
○ IC1, IC22 or HP JACK
IC401
○
○ IC32
Parts with possible defects
TR2, TH1 or D18
Multimeter
(On JK circuit board)
Multimeter IC24
Multimeter IC21
Multimeter IC20
Multimeter IC4
IC23
IC23
Component side