YAMAHA PSR 740 Portatone - Circuit Diagram (Schematic)

HOW TO ENTER THE TEST PROGRAM
AUTO MODE
While pressing the C3#, F3 and G3# keys, turn the [STANDBY/ON] switch on.
MANUAL MODE
While pressing the C2#, F2 and G2# keys, turn the [STANDBY/ON] switch on.
PROCEEDING THROUGH THE TEST PROGRAM
AUTO MODE
When the test program is started, the test is automatically executed.
When confirmation is necessary, the test program stops operating and waits for the instruction. At this time, press the [START/STOP] button; the next test is automatically executed.
MANUAL MODE
The LCD will display “TEST” when entering the test program.
To select the program number, use the [BACK] and [NEXT] buttons.
To execute the test, press the [START/STOP] button.
To proceed to the next test, press the [START/STOP] button.

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DATA INITIALIZATION
All data can be initialized and restored to the factory preset condition by turning on the power while holding the highest (rightmost) white key on the keyboard. “Now initializing the internal memory...” will appear briefly on the display.
• All registration and User Style/Pad memory data, plus the other settings listed above, will be erased and/or changed when the data initialization procedure is carried out.
• Carrying out the data initialization procedure will usually restore normal operation if the PSR-740 freezes or begins to act erratically for any reason.