I had a look at the 5 wii consoles, I recently picked up, today. While 4 of them were working fine the last one had a problem with the screen being out of sync and the picture rolling.
Apparently this is caused by the unit being set to ntsc mode and not pal. I did a quick Google for a fix and found this:

Powering down for 5 minutes
Power on Wii, give it a few seconds to boot
Hold DOWN on the directional pad of the Wii remote
While holding DOWN, press the RESET button on the Wii

and It worked fine so I now have 5 working consoles. I put a disk in and all of the drives work fine.
I checked the remotes next and found a broken sensor bar, it had a dodgy cable so I shortened it. It too works fine now. You can sometimes use the camera on your phone to check if the IR leds are working depending on the phone.
Next were the remotes themselves. Two had bad corrosion so were relegated to the parts bin. One had working buttons but no cursor on the screen. I took a guess that the IR sensor was dud as it still didn't work after cleaning it. I swapped the sensor from one of the non functional corroded units and it now works fine.
So I have 5 working wii consoles with 4 power supplies (all tested), 4 video cables (all tested), 4 sensor bars, 3 nunchuks and a wired game controller.
The next job will be to clean all the remotes and nunchuks.
Cheers Trev.

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