Weird GC PSU Problem

[Crazy Inventor]

So I got back into finishing my GC portable and I've been tying to get my screen to run off it's power supply. The screen is a Haier HLT71 screen and the battery that used to run it is 7.4V. The battery stopped working a few years ago and I've been using a cable I soldered that plugs in to a car adapter that you would plug into your wall (if I made that confusing,I probably did, you use it to power things that have a 12v car plug, in your home). So because of that adapter, I keep thinking that the screen will work with 12V. It doesn't. When I plug the GC power supply into to the screen, the psu craps out and stops working for a few minutes.

I'm not sure if it needs 7.4V or if it's just a werid problem; I'm going to want to find a power supply to power them both but I don't know if I need to get a regulator or just a different psu for this.

 

[sonictimm]

are you plugging it into just the screen, or the whole GCP? it sounds sort of like something is shorting and the PSU is stopping to prevent a blown fuse. Does the screen still work with any other adapters?

 

[Crazy Inventor]

are you plugging it into just the screen, or the whole GCP? it sounds sort of like something is shorting and the PSU is stopping to prevent a blown fuse. Does the screen still work with any other adapters?

Sorry, haven't been on here in a while.

I'm plugging it into just the screen. I don't even turn it on and the power brick will stop working for a few minutes; I'll solder the screen's plug to one of the black and red cables that plugs into to the power switch that the GC plugs into (the little circuit that has the big black button), it'll still work. But plug the soldered cable into the screen and it stops, even without turning the screen on.
And yeah, the screen used to work with a 7.4v battery that was included with it but it stopped holding a charge a long time ago. I don't have any other adapters in the 7.4-12V range; just laptop chargers that are around 18-24V. I feel like the GC's power supply is too much for it, but that's just my assumption.