Brand New Super Nintendo With Video Problem

Hi! I was hoping someone could give me an idea on what's going on here. I have sound and video, however, it displays only a portion of the screen split into 7 horizontal viewing areas - the same portion of the screen in all 7 viewing areas. I have tried multiple tv's, swapped out cables and different games, but the result is the same. I assume its a problem with the motherboard (SNS-CPU-GPM-02), maybe the graphics chip, but I really have no expertise with this type of troubleshooting. Any and all help is very much appreciated. Thanks!

 

Anyone?

 

Do games seem to play fine other than the graphics? If so probably a vram issue reflow the 2 hyundai chips or replace them. Vram failures are rather common and generally don't cause games to crash, though testing for crashes can be pretty hard to do without a game like final fantasy iii or chrono trigger that have a detailed cut scene.

 

Tokimemofan,

Hello, and thank you for your reply.

Yes, the games do seem to run fine, other than the graphics being displayed the way they are.

What would I do with the FF III game? I believe I do have one.

Thanks in advance!

Texian

 

Yup! I have one.

 

Makes sense. Isopropyl alcohol and/or compressed air?

 

wow, that suuuucks. My vote is for VRAM issues as well, though they will likely need replacing. Could be the video processing chips (the two PPUs?) as well. In any case, you can try pressing down gently on the VRAM and video chips while the system is running to see if anything changes. If yes, then its a reflow issue. I recommend removing the bottom metal shielding when doing this (so as not to short anything).

The other thing you can do is (if theres documentation) lookup all the VCC power rails going to the PPUs and see if they check out. If some caps went bad and theres little to no voltage on some essential rails, I could see it causing this problem. The way the glitching is playing out makes me suspect those a little more than VRAM acutally..

You could also use a scope to check PPU clock signals...

With the amount of a work this repair could take it may be worth just swapping the guts with another working system...

-Segasonicfan

 

Segasonicfan,

Hey! Very informative reply, thanks.

I tried pressing down on all the chips while the system was on with no change whatsoever. Also, after overlooking all the caps, I don't see anything out of the ordinary - no leaks or blown caps. PPU's could definitely be the issue. Those things would be a nightmare to replace for a non professional like me. I was hoping to avoid a guts swap, but as you noted, the amount of work may be out of my expertise.

Texian

 

Hey Texian,
yeah, the sad thing is, you don't want to do a job like that and still have the problem persist. The only sure fire thing without probing is replacing the PPUs and VRAM and caps. It's just a damn lot of work. If I had another parts SNES here (i have a ton of system parts) Id offer to do it for ya on the cheap, but alas, I only have NESs here.

-Segasonicfan

 

Segasonicfan,

Probing as in using a meter? I may have access to one of those.

Yea, Ive been looking for cheap spare SNES motherboards to do the swap. I even tried taking it to an electronic game repair store and they just wanted to sell me another system. Its such a shame that this mint condition system may never work as intended. It worked for approximately 5 minutes before the problem came about. At first, I thought it may have been my tv that did it, but I switched to an old CRT and had the same outcome.

Would a burn-in test cart help me identify the problem exactly?

Texian

 

Watch the opening cut scene. Usually if it is not a vram issue the game will crash even if other games don't, chrono works too. If you can load a save, could and ppu issues will often cause battles to load wrong often with impossible battlefield/enemy combinations.
Of course this assumes you don't have a test cart.

 

That doesn't look like the VRAM itself is the problem (no tiles are corrupted, but that should be taken with a grain of salt).

Looks more like a communication problem between the PPU1 and PPU2 chips (broken trace?). The repetition pattern suggests a problem with the control of the VRAM address bus.

 

ah it always feels good to know my thoughts were on the right track! (Im not super familiar with SNES hardware). Yeah, check around for traces and look at PPU clock signals. Seems like a good idea.

Also, you say it worked initially? Even for a few minutes? I highly recommend replacing the capacitors, especially if there are ones around the clock signals. Caps can go bad especially on new systems where they dry out from not being used ever.

-Segasonicfan