Sega Nomad Internal LiPo Mod interference

Hi

A while back I modded a Sega Nomad. I put in a modern LCD and at the same time I also added two 3.7v LiPo batteries to give 7.4v. These are wired to a LiPo protection PCB and then two the battery terminals and also a new DC input jack for charging. The system works great and gives me plenty of running time.

However I have a strange problem with it, I get interference on the screen and also when outputting via the AV out jack. I also get some static with the sound, again both from the internal speaker and through the AV out and headphones.

I would appreciate any advice on how I can remove this video/sound interference.

 

Well it isn't actually anything to do with the battery mod. I've got another Nomad and fitted the new LCD as per this page https://nobitleftbehind.wordpress.com/2014/06/14/fix-for-lcd-replacement-mod-blinking/ I've also done the DC bypass mod so it's running off 5v instead of 12v. If I hook the Nomad up to a TV I can hear the same static as I get from the Nomads internal speaker when the LCD is connected, but if I disconnect the LCD the static also disappears. So it would seem that it is in fact the new LCD that is introducing the visual interference and audio static. Thing is, this is the same screen that lots of other people use, so why am I having these problems but others aren't?

 

Could be the switching regulator on the lcd driver board that is causing the noise, get some images of the board you modded. Often times you can just remove the Regulator chip and just bridge 2 pins together and it'll work fine.

The Gameboy Zero project on sudomod.com uses this same method.

 

Here are a couple of shots of the board.

So should I remove the chip altogether? And if so should I just supply the pad the pin was connected to with 5v?

 

I believe it's the backlight driver circuitry causing the noise, hence why it's normally shielded.

 

Remove the Chip and bridge these 2 points.

 

Does anyone know where the jumper goes, to prevent screen flickering, on the new revision of this board?

Thanks!!