The A2000 returned from the sea

[jman]

Ok, done some soldering play to finally get the A2000 able to boot.

I've plugged the machine with only the floppy disks plugged and powered, all the rest was out (HD, HD card, Supra RAM card).

Well, first the bad news: green screen.
The good news is that my lame CPU soldering works - or was not needed :-)

I checked a couple of other threads here on EAB so I'll spare you the boring list of what can be wrong, I'll go through it by myself:
- CPU and kickstart are ok. The green screen is after their checks, it is telling me that the system could not count at least 256kb chip RAM, correct?
- Any chips overheating? Paula, Denise, MOS and 68000 get pretty hot (can't keep my finger on them for more than 5 seconds), the rest is dead cold, chip RAM included.

It is my understanding that at this point I can narrow the issue to the circuit tracks, there must be a dead end somewhere, correct?

So, what now?

Please let me know if I have overlooked something, any suggestion is welcome (also "put a WTB on amibay..." is accepted).

thanks

EDIT: I didn't mention that at a closer look I've discovered a severed pin on the floppy controller plug on the motherboard. I'm sure this is not the cause, but what the hell, I had to fix this too on the A4000D :-(

[rkauer]

Pin #3 is not present in floppy connectors, it is used as a guide for cable insertion. If it is the case, don't bother.

[zipper]

One possibility: reseat Agnus, check the socket.

[jman]

Originally Posted by rkauer

Pin #3 is not present in floppy connectors, it is used as a guide for cable insertion. If it is the case, don't bother.

You're right, it's pin #3. I was fooled by the fact that in the cable plug there seems to be a pin stuck inside, thanks :-) Nothing to worry about at the moment, though.

Originally Posted by zipper

One possibility: reseat Agnus, check the socket.

I don't have the right tool to extract Agnus MOS chip so I just ensured it was firmly inserted into the socket. Nothing changed.
I will give a more thorough check at the PCB tracks, but I don't have high expectations from such a job.

[jman]

Hello guys, me again :-)

Let's say I want to ensure that tracks between the CPU and Fat Agnus are ok.

Please have a look at the following attachments:
1) How do I have to turn the schematics sheet accordingly to the position of the chip? Is the "1" near Fat Agnus on the schematics and the photo an indication?
2) If I'm not wrong CPU and Fagnus are linked by A1-A23, lower right pins of the CPU, correct?
3) Also, do you confirm that probe positioning is not important? I'm asking because I get different readings if I switch the probes.
Thanks

[psodas]

As you see in fat agnus the number 1 marked on pcb, turn the schematics with pin 1 to the same position.
Also a friendly advice! I believe cause the pcb must go to someone with the skiils to repair it, before after all this experiments is no longer possible.