what is strange is that commodore didn't write any troubleshooting guide to it....
Well they did publish a service manual of course. It's practically impossible to produce a magical guide to pinpoint an exact component failure for anything that could possibly go wrong.
And there's other guides about, such as
this which myself and others have written.
The board should boot to the insert disk screen with just the power supply connected. The Zorro riser board is required for ROMs OS2.x (v37.xx) or greater else you'll get a yellow screen. With the v36.xx ROMs you have, it doesn't need the Zorro riser to boot.
As others have said, the green screen at power on is the result of the hardware test the ROM performs at power on. It performs a simple write + read-back test for the chip memory, and if problems are detected, then it shows the green screen.
The problem isn't necessarily related to the DRAMs (the 8 soldered in ones in the corner), any faults in the bridge logic will result in the same error. And fairly likely to be a result of the battery corrosion if it's bad.
Unfortunately it can be a fairly complex thing to repair if you've not done this level of work before and don't have the right tools. I do component level repairs on A3000 boards. If interested, contact me for an estimate and send a photo showing the battery corrosion:
http://amiga.serveftp.net
