Amiga A2000 powers up but does not start

[Retro_71]

As Homer said what type of monitor?
Also is there any hard drive activity or any clicking or disk accessing coming from the floppy drive?
I would desolder that battery before it spreads to the motherboard (you may want to check underneath the MB as well for any corrosion)

[Retro_71]

With regards to the battery you can replace it or leave out (depends if you want to keep time), only my main A2000 has had it's battery replaced the other is left bare.
Have you checked all the seating of the chips and the cards?
Just press all the chips down just in case some are loose.
also what hard drive card have you got? and does it look like it in good condition?
Check the whole MB for any signs of corrosion.
I'm just getting back into Amiga's myself so i may have forgotten something.

[Retro_71]

Try this site http://www.amigahistory.co.uk/selftest.html It says red means error in rom either not seated properly or it no good...  :-(
I have another link somewhere with a full explaination but i can't find it atm. But i'm sure someone better then me already has the explaination and will give it.  :-)