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Restoring a SNES

mcunerdmcu_nerd wrote 04/10/2019 at 15:30 • 5 min read • Like

Over a decade a go I got a SNES from some relatives.  When I was doing some cleaning I decided to pull it out.  After cleaning the cartridge slot, it was working but the picture on the TV was pretty terrible. I picked up a cheap composite A/V cable and the picture was fine. I initially thought that the RF switch was crap, but upon further inspection that wasn't the case.  This is where the restoration began.

The SNES RF switch coax jumper uses a stranded core vs the normal solid core that's used on most normal 75 ohm TV coax.  This means that the stranded core can't be used as the center pin on the F connector, so what  Nintendo did was attach a solid piece of metal to the end of the stranded core to serve as the center pin. The metal bit tends to be held in place loosely.  Why they didn't simply use standard solid core TV coax is anyone's guess.

The problem was surprising and yet unsurprising

The less than spectacular coax jumper made me think that it was the root of the problem, so I planned to replace the coax jumper.  When I opened the little grey box, the actual problem revealed itself. Two of the three solder joints that connected the coax to the PCB were completely broken; the coax shield joint and a joint that held a piece of metal that was crimped to the coax outer jacket to help hold it down to the PCB and therein lied the flaw that caused the failure.  The crimped metal piece was the only thing that provided any strain relief.  the RF switch is often dangling off the coax connection on the back of the TV so quite a bit of stress gets placed on the connection of the coax to the PCB.  Sadly I didn't think to take a before photo, but I marked the joints that were bad in the after photo below. I also used some hot glue to help provide some actual strain relief so that it doesn't happen again.

After that, I re-assembled the case and plugged it into the TV. It worked just fine. Surprisingly the iffy center pin didn't cause any issues for me.

The next chapter in the restoration was cleaning up and retrobrighting one of the controllers.  The controller wasn't exactly treated nicely by its previous owners and needed a bit of work.  I first disassembled the controller and gave it a good scrubbing. I took a magic eraser to the badly scratched up areas which helped a lot. 

Next was to hunt for something around the house that could serve as the retrobright solution.  After a bit of googling, I learned that many oxyclean stain removers can be used for retrobrighting and the key ingredient to took for was sodium percarbonate which is apparently a source of hydrogen peroxide. I found a box of Biz laundry stain remover in the laundry room as a possible candidate. I looked up the SDS to find out the ingredients and while it didn't list sodium percarbonate, the SDS did list disodium carbonate and in the parenthesis it mentioned compound with hydrogen peroxide.

I added some Biz to a container of water and stuck the plastic controller pieces in it and set it out in the sun for 6 or so hours.  While the result was less than perfect there did appear to be an improvement but the controller wasn't terrible yellowed to begin with. Below and after photos below.

Next came the real challenge, the SNES itself. It was badly yellowed with the exception of a few case pieces that remained the original color.  I made a crude, but effective makeshift screwdriver bit from an old flat head screwdriver to remove the security bits to take the case apart.  After taking the case apart, I gave everything a through scrub. I then filled two tubs of water and mixed in some Biz.  I put the two large case pieces in each of the tubs plus a smaller piece and put them out in the sun for a total exposure of around 14 hours. It made quite a transformation. While it didn't work perfectly, it made a major improvement. 

There was one significant fail though; the power and reset keys. The keys were a bit darkened so I threw them into a small container.  Everything appeared fine but after I left them to dry a bit, I noticed something terrible. A whitish haze appeared!  I tried everything to get rid of it, a magic eraser, vinegar, some diluted bleach and even some automotive plastic polish. Nothing worked.  When they're submersed the haze seems to go away but after it's left to dry it reappears! It's likely that a white haze is on the other parts as well but since they're much lighter colored, it's not noticeable.  If anyone knows of a fix to this please do tell.  In the  photo you can see the power button recently taken out looks fine but the reset button which was taken out earlier really shows the haze.

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