Corrupt graphics

Lhos · Post by **Lhos** » Wed Jan 03, 2007 11:48 pm

First post, first portable. I've been working on an SNESp for the last half a year or so, on and off, and FINALLY, it's almost done. Wired, plays games, controls work (that was a female of the dog species), etc. Now there's a new problem. The graphics are corrupt.

They appear correctly, but fuzzy, pixelated, and incorrectly colored. They have, however, appeared correctly on and off, so I think it's the wire connecting the video. While working, I accidentally ripped off the small tab you solder the wire to on the screen, and had to scrape some plastic away to get a new contact point. I think this is the problem - there isn't a strong enough signal, and that would explain the sketchy performance.

Now - the questions: Is there anywhere ELSE to solder the video wire to the screen, an are there any other possible reasons for this kind of glitch?

Thanks.

*UPDATE* - looked at the screen FAQ, and tried using the composite in pin for the av plug (small, long, white plug). Same result. I then managed to pry up some of the inlaid wiring, and soldered onto that. Now I get negative colors, but no pixelation. So close, and yet so far.

-Lhos

Post by **CronoTriggerfan** » Thu Jan 04, 2007 12:43 am

Hmmm...

This could be a wide array of problems. For one, is your screen getting over the required voltage? That's usually a sign of inverted colors and pixelation. Did you do a cartridge slot relocation? Perhaps a pin got jarred there. And although it may seem tedious, go back and check all your solder joints; a single cold joint anywhere can screw up the whole process.

From the sound of things, though, your SNES motherboard may be shot; worst-case scenario, yes, but your situation has all the right signs. To make sure 100% that this is a problem with the SNES and not the screen, though, try wiring up composite video to the screen for something easy to hook up and see if you get the same distortion problems. Doubt it, but it's worth a shot.

Good luck,
CTFan

Lhos · Post by **Lhos** » Thu Jan 04, 2007 12:54 am

Voltage issues occurred to me - I was just looking through the extremetech site, and saw the 5v wire to the SNES hooked into a different spot than I think mine is. I've been going up and down stairs trying ideas long enough for tonight, though, so I'll get on that tomorrow. Thanks for the speedy response. ^^

*EDIT* The voltage issue seems even more likely now. When I turn the system on, any images that appear go from nonexistant, brighten up, appear normally, and THEN move on to becoming negative. I'll check through the guide and all, and see if that helps.

-Lhos

Krepticor · Post by **Krepticor** » Thu Jan 04, 2007 8:59 am

1) sounds like the cart slot could be dirty, check that

2) try hooking it up to an RCA cable and plugging that ti the TV, if that works then we will isolate the screen

3) CTFan is wrong, worse case scenerio is not the board, but the video encoder being fried, ifthis is the case, then a new one could be added, however, before this feasco even need to be attempted ttry connecting the SNES up in RGB, if it is a mini board you will need a few extra components, but should be able to get it to run

Post by **CronoTriggerfan** » Thu Jan 04, 2007 9:33 am

Krepticor wrote:1) sounds like the cart slot could be dirty, check that

Whoops, never even thought about that, thanks! Also, how many different games have you tested?

2) try hooking it up to an RCA cable and plugging that ti the TV, if that works then we will isolate the screen

Yep. Also, when doing this, try to use the original power supplies if you can, that way you know you're getting just enough power.

3) CTFan is wrong, worse case scenerio is not the board, but the video encoder being fried, ifthis is the case, then a new one could be added, however, before this feasco even need to be attempted ttry connecting the SNES up in RGB, if it is a mini board you will need a few extra components, but should be able to get it to run

Yeah yeah, Mr. Fancypants coming in here to prove me wrong and whatnot.

Kreciptor brings up a good point. If you do wanna try RGB for the SNES, here's how to do the mod. Good luck!

CTFan

EDIT: By the way, does anyone know if there's any way for the PSOne screen to support S-Video?

extremesonic · Post by **extremesonic** » Thu Jan 04, 2007 4:06 pm

CronoTriggerfan wrote:By the way, does anyone know if there's any way for the PSOne screen to support S-Video?

I think in the screen section of the forum, someone(pretty sure it was segasonicfan) found a way to do it. However, it seemed to me, to be more complicated and troublesome than its worth.

Lhos · Post by **Lhos** » Thu Jan 04, 2007 4:56 pm

I've gone back over my wiring, and the voltage lines seem correct. I still think the video contact point on the screen is my problem - it's only a piece of wire that's been pried up from the plastic.

That aside, I've tried two cartridges: Super Mario All-Stars & World, and Stunt Race FX. Both play just fine, graphics aside. To give a better description of what the video is doing: Any images appear normally at first, but then slowly become more and more discolored and pixelated. For example, the background color of the SMAS&W title screen becomes rainbow from its original blue. The writing and characters in the foreground remain correctly colored, but become blurry and pixelated.

Sadly enough, I've never once tried cleaning the cart slot, and it could definitely be dirty. I'll give that a go in about an hour - I've got sushi to eat in the meantime.

As far as the RGB mod goes, I assume the output will then be in (duh) RGB, using those three component wires. I'd need to use the RGB input for the PSOne screen I'm using as well, right? Just making sure before I cause any more damage.

Lastly, I'll also go hunting around for a spare RCA cable. Hopefully that'll work. Considering the screen has been messed up more than the SNES, I'd say it would, but still.

Thanks for the help, all.

-Lhos

**MAJOR UPDATE**
The screen is the issue. I hooked everything up to my tv via composite out, and the image was perfect. I still think my contact point on the screen is the problem. Does anyone else know of another spot to solder the video line to on the screen?

Post by **CronoTriggerfan** » Thu Jan 04, 2007 10:45 pm

Okay, so the screen's the problem. As far as wiring up the video leads somewhere else, the only places I could think of are the ribbon cable inputs and the tabs on the back; you could try sanding the lead that goes to the solder tab on back and solder directly to the line, but it sounds like you've already done that. I'm sure there's an IC somewhere you could solder to, I'm not positive, though. It'd probably require some lead tracing, though.

CTFan

Master of Portables · Post by **Master of Portables** » Fri Jan 05, 2007 12:49 pm

what voltage is your battery rated? if it is higher than 8 volts, then that could be a problem with the screen...

Lhos · Post by **Lhos** » Fri Jan 05, 2007 7:25 pm

Master of Portables wrote:what voltage is your battery rated? if it is higher than 8 volts, then that could be a problem with the screen...

I'm using six alkaline AA batteries. Assuming 1.5 volts each, that's 9 total. However, Ben's book mentions being able to use them, yes? The current gets run through a regulator from the batteries, doesn't it?

-Lhos

Post by **CronoTriggerfan** » Fri Jan 05, 2007 7:27 pm

Lhos wrote:
Master of Portables wrote:what voltage is your battery rated? if it is higher than 8 volts, then that could be a problem with the screen...
I'm using six alkaline AA batteries. Assuming 1.5 volts each, that's 9 total. However, Ben's book mentions being able to use them, yes? The current gets run through a regulator from the batteries, doesn't it?

-Lhos

Well there's your problem! 9v is NOT GOOD!

Use 7.2-7.5v, it'll fix it right up.

CTFan

Master of Portables · Post by **Master of Portables** » Sat Jan 06, 2007 11:40 am

ah, thats what happened with mine too, but i just stopped by radio shack and bought a 7.2 battery. suprising though i can't run my snes with an above 8 volt battery

Lhos · Post by **Lhos** » Sat Jan 06, 2007 5:17 pm

... I think I need a new screen. If I use five alkalines (7.5v), the screen does the same thing, just very dimly. I'm in the process of hacking up a 9.6v Ni-cd pack into a 7.2, but I don't see why it would make any difference. Those alkalines were fresh a week ago, and have had sporadic use for testing. Unless my first idea was right, and the contact point is the problem, my screen seems to be fubar'd.

Kurt_ · Post by **Kurt_** » Sat Jan 06, 2007 6:30 pm

But alkalines (new ones) are not 1.5V to begin with. THey have a steep discharge curve, and so being around 2.5V (I believe). If you're using absolutely new alkalines, try the pack. Also, follow the wires on the back of the board. Somewhere on the right side near the bottom there is a spot to wire up composite video. I'm not quite sure where though.

I started with a zenith screen (repackages PSOne screen) and the composite video wire was hooked up there.

vskid · Post by **vskid** » Sat Jan 06, 2007 6:59 pm

The composite signal might need to be filtered. With the screen I got from a dvd player, it did about the same thing until I got the cap and inducer from the player and put that on my signal line.
Just don't ask me what value you need, I have no clue.