Purple screen of death with PC Engine?

A few weeks back, I installed an RGB amp into a PC Engine, but I had been having trouble with it. It turns out I had a dud amp, but just before I figured that out, I had been getting a purple screen on bootup. Even with the RGB mod removed, I'm still getting the purple screen. Any idea what the solution to this is?

 

Don't know of how to help here, but in the worst case you have fried the VDC / VCE.

What was messed up with that RGB amp in the first place? May be from there it is easier to see what could have had caused the present problem.

 

The one of the amp's input/output wasn't working (i.e was only getting two colors). How would I have fried the VDC/VCE when the mod only involves soldering to the contacts on the EXP slot? :\