As batteries drain, screen gets distorted

SteelFox15 · Post by **SteelFox15** » Wed Oct 25, 2006 6:22 pm

I've got everything all wired up correctly, as far as I can tell, using the TI switching converter with the inductor to power the N64. Everything's running off the batteries, screen included and when the batteries are fully charged and the system is turned on, it looks great. However, after a little while (15-20 minutes), lines begin to form on the screen and erratically travel up and down. As time goes on, this gets worse and worse until it is barely playable. I've kept the system on after that and eventually the backlight cuts out and the screen goes dark, even though it's definitely still on.

I'm using these batteries; there will eventually be multiple packs wired in parallel, though I've only been testing one at a time and the problem persists regardless of which pack I use.

I'm assuming that the problem is caused by the voltage drop that occurs as the batteries drain, though the voltage never drops too low, at half a charge the thing still reads like 7.2V, so I don't know why the screen is still responding this way. Any ideas or suggestions? Thanks.

timmeh87 · Post by **timmeh87** » Wed Oct 25, 2006 10:08 pm

which TI regulator?

daguuy · Post by **daguuy** » Wed Oct 25, 2006 10:47 pm

i used to have this problem. it was caused by the batteries not charging all the. make sure your charger charges them completely. if not, get a higher amp charger and see if that helps. it helped me but i use NiMH and not lithium

SteelFox15 · Post by **SteelFox15** » Thu Oct 26, 2006 5:04 am

timmeh87 wrote:which TI regulator?

PT78HT233

Oh, one thing I forgot to mention. When the N64 is hooked up to the TV instead of the screen, there is no distortion even just before the batteries die.

daguuy · Post by **daguuy** » Thu Oct 26, 2006 6:30 am

that's because N64s can run on slightly less voltage than psone screens

Krepticor · Post by **Krepticor** » Thu Oct 26, 2006 9:43 am

yea that is a problem I had and then the screen would kinda die and the n64 would act like it was dead...freaked me out

Also, I don't know why, but the power drain overdrives and distorts the speakers before the dreaded screen distortion... just so everyone knows of a symptom...

And Yes I use Lithium Ion batteries and get this

SteelFox15 · Post by **SteelFox15** » Fri Oct 27, 2006 2:18 pm

daguuy wrote:i used to have this problem. it was caused by the batteries not charging all the. make sure your charger charges them completely. if not, get a higher amp charger and see if that helps. it helped me but i use NiMH and not lithium

I'm pretty sure the charger works okay. I mean, it's outputting the correct voltage and the batteries do the same after they're charged (well, slightly higher, closer to 8V).

But does anyone have any ideas on how to fix the problem? Is there any way to step up the voltage a little or something? Also, would LED modding the screen help at all? I don't know which parts of the screen are causing the distortion, but if getting rid of the circuit that goes to the inverter and whatnot would help keep voltage higher, I'd do that.

SteelFox15 · Post by **SteelFox15** » Wed Nov 08, 2006 7:23 pm

Okay, so I think I fixed the problem. I got one of these guys from TI and everything seems to be working okay. I'll have to test it for a while to see how well it holds up as the batteries drain closer to zero, but so far so good.

timmeh87 · Post by **timmeh87** » Wed Nov 08, 2006 7:48 pm

so you stepped up the votlage to 15v... and used a regulator on the screen?

SteelFox15 · Post by **SteelFox15** » Wed Nov 08, 2006 7:58 pm

15V? No, it steps it up to 8V. Although I'll lose a bit of battery life for this, I think it's worth it to get rid of the distortion.