Hardware test

System ROM functionality. Navigate through screens by pressing start. Quit by resetting the system.

=Crosshatch=

See Crosshatch.

=Color test=

Can help diagnose color issues.

=I/O test=

Allows to check joypad inputs, hardware DIPs, test and service buttons, the marquee and credits displays.

Warning: the inputs are active low. Ground = "1" = pressed.

=Sound test=

Plays an intermittent 524Hz tone on the left, right or both speakers. Recording:

=Memory card test=

...

=Backup clear=

Press the A, B and C buttons at once to erase and format the backup RAM.

=Calendar setup=

See RTC.