Yamaha disklavier MX-100A, Service Manual

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4) Switch Test
The 7-segment LEDs display the number corresponding to each switch.
Foot Switch=40
5) RAM Test
Write, Read, and Verify operations are conducted, then the result is displayed. ( O K ! ! / N G ! ! )
6) ROM Test
The checksum of ROM B is calculated, and the result is displayed. ( O K ! ! / N G ! ! )
7) MIDI Test
The MIDI IN and MIDI OUT terminals of the controller are directly connected, and the result is
displayed. ( O K ! ! / N G ! ! )
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