SNES garbled video with perfect sound.

Picked up a SNES from the Flea Market this weekend. When I got home and tested it, it has garbled graphics but perfect sound. I am using, in this case DKC 1.

1. This cart is clean and works with my other SNES.
2. I am also using the AV and Power Adapter from my other system and they also work.
3. Tried a working RF just to see if that would work but nothing changed.
4. I dissembled the unit to clean. This is a Model 01 NTSC board.
5. I cleaned every solder joint and the pin connector, which in this unit, is the detachable one.
6. No noticeable broken traces, leaking caps, or otherwise weird looking areas on the board.
7. I have ran out of obvious things to check. I have attached an image of what the screen looks like when the system is powered on. My first thought was that it is a bad connection but after triple checking all the joints and contacts I 't know how it could still be. I am worried its a PPU issue or other chip related issue of which I know where to obtain those chips other than another system which defeats the purpose.

Any assistance would be grateful.

P.S. The second image is SMW which at least shows some images but obviously with issues.

 

I'm having the same issue with my SNES; just started after getting it set backup after spending a couple years in storage. The distortion I'm seeing doesn't seem to be quite as bad as yours. I check all the same things you did and have been scouring the internet for possible solutions. If you haven't seen it, you should check out this thread: http://www.assemblergames.com/forums/showthread.php?47286-More-SNES-mainboard-repair!
After reading through it, I'm thinking I might trying baking my motherboard. I'm a professional computer/network tech, and I've had success repairing PC and laptop motherboards (and some printer boards too) by baking them to resolder connections that would otherwise be impossible to fix.

 

So, since I couldn't find any other leads on possible fixes, I tried baking the main board tonight. I kind of chickened out a little bit though since the plastic piece on the back of the board (where the power and AV cables connect) does not appear to be easily removable. I baked the board a little cooler and less time than I was planning on. No change at all in the video. I plan on baking it again sometime in the next couple of days at 415'F for about 10 minutes.

 

The plastic piece is easy to remove,just need to desolder from the bottom of the power jack.

Also check the board for any broken traces before you go and bake it.

 

Yes, start by a good visual inspection of the board for broken trace and cold solder joints. "Baking" is not a very good idea.

 

First of all, this is comparable to saying "I am a professional milkman, so I know what I am doing with repairing PCB's"

Second, BGA chips are perfectly repairable without baking them in an oven. They just require specialized tools to do it properly. The fact people just throw them in an oven and consider it pro (or even a decent repair) is just stupid.

That said, looks like damage trace to vram to me (or a damaged chip). It would be easy to remove the chip and test it - if you had the correct tools for the job. You should just use a multimeter and test the connections between the ppu's and ram chips to ensure they are all connected.

 

Baking? What the hell is this crap? Get a multimeter, test for capacitence, continuity, etc. Find broken parts, replace via soldering.

If you don't know where to start here's a video from the 1990s:


Ovens at home are for baking or broiling delicious food. Not to put your pcbs with lead and other dangerous metals inside.

 

Hope this helps.