Today I got my A520 modulator. I connected it to the A4000, then to the TV on composite, turned on... and nothing again, just the white screen. And no floppy activity. All subsequent boots gave a black screen and no floppy activity.
Now I noticed the motherboard power cable is getting hot. Not a good sign. Oh boy, I fear I will never see my A4000 working again!
I was so excited... well... I guess I'll disassemble it, remove the battery, reassemble and hope for a small miracle... I'm on holidays now, I'll do it next Monday.
In the meantime... if you have any suggestions, I'd appreciate them very much.