A4000 blue screen trouble

[recidivist]

Just got this 4000 with Toaster and Flyer.
 Hooked it up to 1084 ,no display,hard drives spin,etc.
 Removed Toaster and Flyer boards-now get blue screen instantly on power on,hard drives spin,leds light up.Blue screen solid,no messages,no changes.
 Stripped system bit by bit and nothing changes-still blue screen instantly on turning on power switch.Have even removed riser board and 040 cpu card.
Still blue screen in a fraction of second of  pushing power switch.Blue screen is solid ,unwavering.Presume this means video circuit is ok.
 Some corrosion near battery.
A4000 Rev B motherboard-all chips except ROMs and U103 appear soldered directly to the motherboard.
Two white stickers on motherboard :A4000 NTSC and A4000 Card Rev D
 Did I just waste a couple days pay?
What should I do next?

[recidivist]

Have now removed the motherboard from the case ;plugging in power supply and monitor then turning on power =no display not even the blue(s).
 Anyone have a motherboard reasonable or can repair this one?

[recidivist]

OK,CPU(3640 ),riser,memory,hard drives all back=blue screen.
Add Toaster 4000 kills screen
remove Toaster and add Flyer =blue screen
Add Toaster to Flyer kills screen.Take Toaster back pit=blue screen again.
Add floppy still blue screen and floppy led staying on.

System was supposed to be workong ok as 4000/Toaster/Flyer about six? years ago.