Psone screen problem

confuserized · Post by **confuserized** » Thu Dec 25, 2008 11:52 pm

I wired up my gamecube to the psone screen. It looks a little bit grainy when I use the gamecube PSU.
like this

However, when I use the battery, the screen goes like this

I am using a switching regulator, and would that affect the screen?
This is the battery
http://www.all-battery.com/li-ion186501 ... leads.aspx
So how should I fix this?

Kyo · Post by **Kyo** » Fri Dec 26, 2008 3:23 am

did you connect the grounds?

Mario · Post by **Mario** » Fri Dec 26, 2008 11:20 am

Switching regulators cause electrical noise, which can interfere with the screen's picture. I think you put a capacitor across positive and ground to fix that. Make sure the capacitor's positive end is on the positive rail, and that the voltage rated for the capacitor is at least twice the voltage coming from the regulator. Also, put the capacitor after the regulator.

confuserized · Post by **confuserized** » Fri Dec 26, 2008 11:42 am

What does the uF of the capacitor have to be?

Mario · Post by **Mario** » Fri Dec 26, 2008 12:12 pm

It really doesn't matter, you can use from 10 to 100 uf.

confuserized · Post by **confuserized** » Fri Dec 26, 2008 1:21 pm

When I add the capacitor, it still doesn't work.

Kyo · Post by **Kyo** » Fri Dec 26, 2008 1:27 pm

you're powering both off the battery right? This does sound like it's the regulators fault. (Given that it's not being used when you use an adaptor)

Do you have an oscilloscope by any chance?

confuserized · Post by **confuserized** » Fri Dec 26, 2008 1:42 pm

The regulator is lowering the input voltage (battery, PSU) to 8v. And I don't have an oscilloscope

Kyo · Post by **Kyo** » Fri Dec 26, 2008 1:44 pm

so you're using it in both cases. Then it's probably not the problem. Unless maybe if the PSU has a different voltage than your batteries

This would make sense if you were like using a battery for one thing and a PSU for another...

confuserized · Post by **confuserized** » Fri Dec 26, 2008 4:37 pm

The PSU puts out 12v, and the battery is around 15 to 16 volts. The switching regulator is working correctly.

Kyo · Post by **Kyo** » Fri Dec 26, 2008 4:44 pm

I'm just suggesting that at a higher voltage it has more switching to do

confuserized · Post by **confuserized** » Fri Dec 26, 2008 6:21 pm

I think the problem is that there is interference from the switching regulator. When I use the 8v linear regulator that came with the screen, the picture is perfect.

bacteria · Post by **bacteria** » Fri Dec 26, 2008 6:32 pm

? Try using some shielding ?

confuserized · Post by **confuserized** » Fri Dec 26, 2008 6:33 pm

That's the plan.
Now I just need a box that's not too big.

Kurt_ · Post by **Kurt_** » Fri Dec 26, 2008 7:00 pm

1) 12 Volts into the screen seems dangerous. It's unregulated, and any high I believe causes permanent damage. Besides, you don't NEED 15 volt batteries, split them into 8 and you can double your life. [But I think you're powering the screen from a regulator on the GC board, right?]

2) I'm surprised nobody mentioned CURRENT. The switching regulator likely outputs 500mA to 1A, not enough to power everything, which will cause distortion exactly like that. Check the regulator's ratings. I bet the linear regulator gets frigging hot, right?