Technics SX-PR1000, Service Manual

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If no sound is generated or if the sound is distorted, the sound
generator ROM corresponding to the key position is defective.
2. For confirming the output pathway from the sound generator.
(Fixed scale, no touch)
The Lch and Rch sound outputs are confirmed separately.
3. Generate a full amplitude sine wave in the pitch of each key +2
octaves. (No touch, fixed stereo center)
By generating a sound frequency outside the normal keyboard
zone, you can confirm whether or not there is an abnormality in
the sound output frequency zone.
4. Generates a full amplitude sine wave in the pitch of each key -2
octaves. (No touch, fixed stereo center)
By generating a sound frequency outside the normal keyboard
zone, you can confirm whether or not there is an abnormality in
the sound output frequency zone.
5. Generate a sine wave in the pitch of each key with touch.
You can confirm if the volume changes depending on the touch.
6. Generate a full amplitude sine wave in the pitch of each key at a -
16 dB volume. (No touch, fixed stereo center)
You can confirm the same sound output as in 1, at a lower volume.
10. PRECAUTIONS BEFORE SERVICING THE MAIN
CIRCUIT
This model employs a FLASH ROM (EEPROM) for the PROGRAM ROM. If changing this ICs,
service the MAIN CIRCUIT as explained here following.
10.1. About the FLASH ROM
The FLASH ROM can be electrically erased and rewritten. This model is designed so that the
repair technician can easily write and change programs and data in the FLASH ROM, by using a
floppy disk.
Figure-30
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