AES Screen Colour (Self Test) - White?

Anyone seen an AES show a white screen when there's no cart in there? The AES is functional - just got a wierd intermittant PCM issue which I am thinking could be bad caps, perhaps the YM3016D, intermittant connection on a trace (cart slot is super clean and good as new), or maybe a glitchy YM2610 (I hope not). But I was just curious about the white screen, I've never seen that before when there's no cart...

newer unibios and no error = white screen

Thanks Raz, that"s exactly what it is! =D