My ongoing adventures with my A2000.

[sprocket]

both floppies dead?

hmmm...I didn't think the 2000 would even try if there wasn't a working floppy.

there's a jumper that has to be closed if it has two floppies in it, btw.

Is the screen just doing a flicker/cycling like it's rebooting?  the LED on the keyboard lights every few seconds and the power light dims?

what colors does the screen go through?

do you know what ROM is in it?

If you disconnect the hard drive and or remove the scsi/ram card can you get the boot prompt screen?

if so there may be something wrong with the config, the hard drive, the ram or some app it's trying to run in startup.

just a few thoughts.

[sprocket]

are you sure the megachip was seated properly?  jumper clip attached?

I had two 500s give me the green screen before I realized they had chip seating problems and given you took the thing out and had another agnus in there I'm wondering if things might just be a little loose...

[sprocket]

I'm waiting on a PLCC Extraction tool to turn up so that I can replace it safely and ensure it's actually that,

I think I remember having done it both ways and as long as you're careful it's ok...but waiting won't hurt.

[sprocket]

There's a mild increase in speed, according to the sysinfo, but bizzarely the workbench rendering seems to have slowed down dramatically! ie open a drawer and each icon is drawn, but much more slowly than before.

do you have the jumper clip attached and to the right pin?

I still haven't removed the battery, should it just pop out, or do the mountings have to be snipped?

it won't "pop out".  Ideally it needs to be desoldered and that required removing the motherboard from my 4000 to do it properly.  You may be able to get it off with a Dremel with a cut off wheel but be careful.  

I have actually twisted the batter away from the metal contacts on each end but I wouldn't recommend that....too much torquing of things.

Batteries are attached at three points and these extend through holes in the motherboard and are soldered.  Holding a soldering iron to the top side (battery side) probably won't heat the solder enough to get it to flux and pull it off.

[sprocket]

on the battery....

one thing some do is after successfully and cleanly desoldering the old battery, solder wires into the connection points with enough length to mount a battery compartment off the mother board.  That way you can put a replaceable battery of appropriate voltage in the holder and change it out when needed.