Psr-S950 Dm Circuit Board Check Method - Yamaha PSR-S750 Service Manual

PSR-S750/PSR-S950

PSR-S950 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
q No LCD display with Power SW ON --> Check items 1 to 4 sequentially
w No sound or distorted sound --> Check items 1, 5 and 6
Test Point
NO. Test Point
1 5V 5V power for analog circuit
2 1.5V 1.5V power for digital circuit
3 1.2V 1.2V power for digital circuit
4 RESET CPU & memory reset signal
DAC output L channel
5 OUT-L
DAC output R channel
6 OUT-R
Note1: Use the standard AC adapter PA-300C for check operation.
Note2: It measures by opposite DGND except special notes.
76
Circuit Judgment criteria
There shall be audio output
(AUX OUT) without distortion.
There shall be audio output
(AUX OUT) without distortion.
DM Circuit Board (WZ493400)
Measured by
5.0V±0.2V Multimeter
3.3V±0.1V Multimeter
1.2V±0.1V Multimeter
3.3V±0.3V Multimeter
Signal Checker
Signal Checker
Parts with possible defects
IC804
IC619 or IC620
IC208
IC4
IC801or IC807
IC801or IC807
Component side