Came across a Super Famicom Jr console for sale at a goodwill with a note on it that said it only outputs gray blurry images, with no further details. I thought that was interesting because as far as I know the SNS-101 (USA version of SHVC-101, they are identical internally. SHVC-101 is the Japanese version) console, which is a later model doesn't have the TC1 trimmer capacitor on the board that could be adjusted on the earlier models in order to fix the black/white video output. So I thought to myself I wonder what is causing the video output to be black/white only. So being the curious individual that I am I purchased the console and brought it home to see what I could find on my test bench.

So before I started disassembling the console, I decided to test it, and yup that is indeed a "gray" (black and white) image. Takes me back to the Mario games on the Game Boy, which were only black and white by design. Unfortunately Super Mario World loses much of its charm without its color.




Not sure why they thought the image was blurry, it looks normal to me. So the only thing left to do is to crack this baby open and start inspecting the board...

Here is a picture of the internals, and as I recalled the TC1 trimmer capacitor is not on these models. See picture for what I am referring to, as indicated by the blue box on the PCB. You can blow the image up by clicking it in the post and if you want a higher resolution version open it in another tab/window.



Well it didn't take long to notice that this system had been previous worked on or atleast opened up. As you see in the picture above that is how it was when I opened it. Yes there is indeed no screws and the PCB just pulled right out. I will have to find some spare screws for when I reassembly this console.

The initial inspection of the top side of the PCB doesn't show any visible damage that can been seen with the naked eye. That being sad as soon as I flip the board over it becomes obvious what went wrong with this console....




As you can see in the picture there is a board that didn't come with this console from the factory. This board is known as a SNESRGB board and its supposed to clean up/restore RGB output on the SNES. Unfortunately it looks like this was installed incorrectly and might be the reason this console only displays in black & white. There are some components like  C11 Capacitor that need fixing and some other solder joints that are a bit messy. Most of these are just cosmetic but since I am here I might as well repair it. I have put some pictures below showing the rough soldering job. 






Here is a close up of the SNESRGB board. 3 Soldering pads are ripped off the board and there is damage to the traces. Definitely a rough job for sure. I wonder what lead to this, unfortunately I won't ever know as there is no one for me to ask.

 

A quick look at the SNESRGB and its not difficult to see the damage. Clearly this has seen better days. Based on this I decided to just remove this board to test the SNES Jr to see if it fixes anything. The other components I will clean up, as most of the problem is cosmetic.

A full video of the repair will be posted. So stay tuned for that.

Part 1 of the repair will be posted 9/30/2024 @ 8:00AM. I decided to split this repair into 2 separate videos due to the length of it.

I have had a lot going on and some of my repairs have been put on the back burner for a month. Finally got around to finishing the repair for this SNES Jr console. The video can be found below if you prefer watching to reading.

According to online resources there are a few reasons why a SNES Jr console can have video output and be missing a single color. This particular console is missing the the B in RGB output, meaning the blue signal is missing, thus there is no blue output.

From what I could find there are 3 components that can cause this problem:

• 21.47727MHZ Crystal
• S-RGB Chip
• 1 Chip

Unfortunately if it is the 1 Chip it means there is internal damage and the only way to fix the console is to have a donor 1 chip to replace it. That being said we can replace the 21.47727MHZ Crystal and re-flow the S-RGB Chip and see if that fixes the problem.

I replaced the 21.47727MHZ crystal and it didn't fix the problem. Tested again with an oscilloscope and by hooking the console up and loading up Super Mario World.

After that I re-flowed all solder joints on the SRGB chip and again there was no change. Unfortunately it seems the 1 Chip is the damaged component in this console. Now all repairs are successful, so what I will do is reassemble this console and keep it in case I run across a console that has some type of other damage and I can use it as a donor to replace the 1 Chip in this console. That being said the console does work, it just outputs without the blue signal resulting in the colors being displayed incorrectly.

If you have access to an oscilloscope you can test the RGB signals on this board to verify where they are broken. I used an oscilloscope to do that and the crystal is generating the correct signals, and they can be tested for and seen with an oscilloscope going into the 1 Chip, but the blue signal isn't present on the other side, which can be tested by checking pin 158 on the 1 Chip processor. So unfortunately this means the 1 chip has internal damage. This can be seen in my video where I show how to test for this. 


Conclusion:
Console partially fixed after removing the damaged SNESRGB board from the console it stopped displaying in black and white and started displaying with partial color, specifically Red and Green. Unfortunately the 1 Chip is damaged and there is no blue signal present.

See picture below for how it displays games... It certainly is a big improvement over the black and white output it had originally. That being said if you have played these games before you will immediately notice the color isn't correct and the blues are missing.



Video will be live 11/10/2024 @ 8AM Eastern Standard