Kurzweil K2600 Series, Руководство по обслуживанию

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5-12
Troubleshooting
Audio Problems
Audio Problems
Note : If you are diagnosing a K2600R rack unit, you can check for audio without having a
controller connected. Connect a pair of headphones, turn the power on, and press the
Cancel button. While pressing the Cancel button, press a few of the alphanumeric
buttons. If the audio portion of the K2600R is functioning properly, you should hear notes.
Intermittent or No Audio
1. Check the fl at ribbon cable at location J808 on the CPU Board to J601 on the Audio Board.
Disconnect and reseat the cable.
2. Check solder connections.
3. On the DSP Board, make sure that U1, U7, and U34 are labeled 7z04.
No Audio, Distortion, or Noisey Outputs
Right Channel
1. On the Audio Board, check the DACs (AD1865R) at locations U2 and U3 input pins 2 and
3 and output pins 12 and 13.
Left Channel
1. On the Audio Board, check the DACs (AD1865R) at locations U12 and U13 input pins 2
and 3 and output pins 12 and 13.
Full volume static distortion after 10-15 minutes of warm-up then locks-up:
1. On the DSP Board, check U2, U3, U5 and U6 (Hobbes ICs). May be heat sensitive.
Different clicks and pops on each effect or consistent ‘thumping’ noise in all
outputs:
1. Clean contacts and re fl ow solder on Audio Board to Engine Board cable connectors.
2. On the DSP Board, check the signal lines for the components at the following locations:
• Check U25 through U28 (effects RAM).
• Check U8, U10, U11, and U13 (LISA ICs).
Boots up normally but has no sound,
1. On the Engine Board, check the clock signals to the components at the following locations:
• Janis ICs, U17 and U18
• ICs U21 through U24, and U28.
• Sound ROMs, U32 and U33.