Archos Recorder 20 - damaged after upgrading with 8MB?

[aspartam]

Hello,
I've upgraded my Jukebox with an 8MB RAM and started it after that.
Everything seems to be normal but one minute later the jukebox hang-up.
When I start it now I can only hear the HDD spinning and see the green led but the display doesn't show anything.
I'm not able to install the 8MB software on the Jukebox so at the moment there is the old 2MB software inside.

I can't find a mistake.
I'm studying Electrical Engineering and I did such kind of soldering work a lot of times.

Does anybody has an advice what to do now?

thanks a lot


Edit:
Now I made to install the 8MB software on the JB and it worked for some minutes.
After two tracks everything disappeared on the display and now I have got the same problem.

Here is a Picture of my Recorder:
http://xs230.xs.to/xs230/08310/juke462.jpg

I soldered it with magnet wire.
I've tested every connection and was'n able to find solder bridges or bad soldered parts.