Airport reception poor after hard drive replacement and adding RAM

Hi

I replaced the hard drive on my old iBook G4 and replaced a 512 RAM with a 1 GB SO-DIMM.

It seems to work. Before I did that I cloned the drive. It runs with OS 10.5.

After booting it recognised my WLAN, but did not accept the password. I experimented with that but it was not the problem. Reception is very low. When I put the iBook next to the WLAN router, it works. When I use the much closer Time Capsule with WLAN switched on, it works.

So: WLAN works, but with much poorer reception. The router is unchanged, my Macbook Pro works without any problems.

Any ideas? Changing the antenna seems to be a bit of an overkill:

iBook G4 12" 800 MHz-1.2 GHz Inverter/AirPort Cables Replacement

Cheers.

Seb.