Power Problems; Dead: Leds, Lcd Backlight, And Xd Card Socket Not Lit; Audio Problems; No Audio - Kurzweil PC3x Service Manual

Troubleshooting & Maintenance

Power Problems

Power Problems

Dead: LEDs, LCD backlight, and xD Card socket not lit

Before opening the unit, verify the following:
1. The AC outlet is supplying power.
2. The AC cord is good and properly connected to the unit.
3. Check fuses. The fuses are located in the power entry module on the rear panel. See the
4. Place the PC3x upside down on a flat protected surface.
5. Remove the seven screws that secure the access panel and set it safely aside.
6. Disconnect the stranded wire cable at J21 on the Engine Board. Refer to page 9 of the
7. Open the unit.
8. Disconnect the stranded wire cable at J301 on the Connector Board. Refer to page 3 of the
9. Refer to the Connector Board schematics, see page 6-14 in Chapter 6, and verify the AC

Audio Problems

No Audio

1. Run the Scanner Diagnostics to check the volume slider operation.
2. Refer to the Interconnect Diagram.
3. Check the flat ribbon cable from J18 on the Engine Board to J302 on the Connector Board.
4. Check the solder connections at the connectors.
5. Refer to the Engine Board schematics and check the signal activity on the DAC, U33.
6. Trace the signal path from the Engine Board through the Connector Board to the audio
4-14
instructions beginning on page 4-18 to convert the voltage. Be sure to check the red
voltage indicator on the power entry module and verify that it is set to the correct voltage
for your location. If a unit set for 120V is plugged into 240V, the fuses will blow
immediately but no damage should occur to the unit.
Engine Board schematics, see page 6-11 in Chapter 6. Verify the voltages at the connector.
• Pin 1, ground
• Pin 2, 5 volts
• Pin 3, -12 volts
• Pin 5, 12 volts
Connector Board schematics, see page 6-14 in Chapter 6. Verify the voltages at the
connector. (See Step 6.)
power voltages at J324. If these voltages are present and correct, replace the Connector
Board. If these voltages are incorrect, suspect the transformer or power entry module.
jacks.