seeking SNES console help (circuitry)

[mrlame]

Hello, brand new to the forum and first wanted to ask if this the best place to ask for information with regard to repairing/diagnosing the SNES console problems I'm having. If there is potentially a better suited forum or even discord server to ask these questions then I will take them elsewhere.

I currently have 2 NTSC Super Nintendo systems that I've run into issues with.

#1) SNS-CPU-GPM-02 - Owned this system since it was brand new (mid 90s) and have had no issues at all with it... until I decided to recap the motherboard.
- I purchased a capacitor kit from console5 a while back and double/triple checked all the components matched and were the correct polarity.
- Upon starting the system up after this, it worked fine.. for about 20 minutes, and then it suddenly went to a black screen with several little white dots flashing sporadically.
- The system still powers on (fuse still works), and the red light displays it's powered on, but I get no picture/sound from it anymore. I'm guessing the CPU was fried somehow but I don't know for certain how to verify this or diagnose what caused this.
- Any advice on where to probe or how to approach this issue would be more than welcome.

#2) SHVC-CPU-01 - Recent Ebay purchase to replace my now non working system. I ran the break-in test rom to check for any issues, and it all passed without issue.
- I quickly noticed graphic/video issues on many games that show up, seemingly, as wrongly colored horizontal lines. sometimes these lines are larger stripes, and other games, the majority of the screen is a distorted color. I've noticed they're more common when there are shifting sprites on that particular axis. Kind of hard to explain beyond that.
- Is this issue caused by a faulty PPU, and if so would it be easy to determine which one? or perhaps its a RAM issue?
- And if one of these PPU chips is faulty, is it viable to transplant one from my other busted system?

I do have a third SNES GPM-02 system that I've just recently recapped and installed Voultar's edge-enhancer kit in. Looks f'ing amazing on my Panasonic Tau 27" CRT.
I do have a logic probe, multimeters, component testers, soldering & hotair tools, Before jumping into trying to figure it all out from scratch, I figured someone out there might have more experience than I. Any help or info on these issues is much appreciated.

Thanks
-Jacob

[KPackratt2k]

The Console5 wiki has a helpful troubleshooting guide, which should be useful for determining which chips are likely to be faulty.
https://wiki.console5.com/wiki/SNES#Con ... stic_Table

It's possible that the 5V regulator has failed on your GPM console. Try replacing that first before moving onto replacing additional components on your SNES consoles. I once replaced the regulator on an SNES console with an L7805CV and it resulted in Super FX games boot looping the console because the new regulator didn't have enough current to power it. The recommended voltage regulator you'd want to use for an SNES is an L78S05CV (note the "S" in the part number), which is obsolete and I don't know if it's still in stock. There may be other suitable 7805 regulators with enough current capability which you can try. I do have a spare regulator (salvaged from a dead SNES motherboard) which I can send you if you're having trouble finding a suitable modern replacement.

One thing you could try is transplanting chips from one console onto the other. I would start with transplanting the RAM chips from your GPM console onto your SHVC console as those are easier to replace than the processor chips (PPUs and CPU). If that doesn't solve the graphical issues, move onto transplanting the two PPUs (start with PPU1, then if that doesn't fix it, move onto PPU2). Bear in mind that the PPUs (and the CPU) are quad flat-package chips with fine pitch, so they will be difficult to transplant.

Before doing any work, I would recommend cleaning the cartridge slots and game cartridges to rule out the possibility of faulty connections.

[mrlame]

It's possible that the 5V regulator has failed on your GPM console. Try replacing that first before moving onto replacing additional components on your SNES consoles. I once replaced the regulator on an SNES console with an L7805CV and it resulted in Super FX games boot looping the console because the new regulator didn't have enough current to power it. The recommended voltage regulator you'd want to use for an SNES is an L78S05CV (note the "S" in the part number), which is obsolete and I don't know if it's still in stock.

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This seems to have been the issue, the old 5v regulator replaced with the L78S05CV you referred to and its now back up and running. Many thanks!

and yea transplanting these types of ICs would be a challenge but it's good to know that they should be relatively compatible if it came down to it.