SCART to JP21 Adapter - Solderless DIY

Most of my consoles are setup for RGB output via SCART connection, and SCART cables and converters are much easier to find than ones wired for JP21. However, my XRGB-Mini Framemeister  only takes JP21, so I've searched all over for a low-cost SCART-to-JP21 adapter to no avail. There's one from a store in the UK that costs like $40+international shipping, which is just too expensive, IMO, and a SCART-to-Framemeister-mini-DIN from retro_console_accessories on eBay (the source for the best-quality retro gaming cables anywhere) for ~$30, which is a bit more reasonable but would cause wear-and-tear on the Framemeister's already-finicky mini-DIN port. Neither of these options seemed very attractive to me, so I figured I'd try the DIY route using a cheap Chinese SCART-passthru-breakout-whatever available for <$4 shipped on eBay:

I'm not altogether sure what the intended purpose of these things is but whatever...

They're sealed shut pretty well but the most effective strategy for cracking them open seems to be applying steady pressure on the sides toward the female end (the curved/scalloped part next to the male end is stronger). I used a C-clamp and slowly tightened it until the clamshell halves started buckling and then popped apart. A bench vise would work well, too.

Once you pop it open, you can cut the wires from the breakout jacks, which will clean out some of the rat's nest inside. In my case, all of the wires were black, which... isn't great:

The input/output switch isn't glued in, so you can remove it and save it for another project.

The female side is soldered in and attached pretty tightly, but the male end is actually pretty easy to work with. Each of the spade-type prongs is secured with a little popout leg in the middle. You can squeeze that in with needle-nose pliers and then press the whole prong inward and pull it through from the inside:

Here you can see one of the removed spade-prongs, with the popout locking mechanism.

Once they're all pulled through, you can rearrange them to match the JP21 pinout and push them back through, as per this key (not my pic, but I'm re-hosting it here because the original Tinypic hosting could vanish at any time):

You'll notice the SCART side has one less ground and one more white, unlabeled prong than the JP21 side. I just left that prong out entirely (#12) and everything still seems to work fine.

Once the prongs are all reordered, you can use a small pokey thing to engage the center-locks, no soldering required. I used a cheap dental tool I had laying around to do the job, but those little pointy electrician's tools (the ones that look like dentists' tools with screwdriver handles) should work fine, too. After that, just glue the casing back together and you should be all set.

SNES to NES Controller Adapter

Historically, the SNES was originally intended to be backward compatible with the NES, with a CPU from the same 6502 lineage as the NES and a similar controller signal protocol over the same 5 wires: data clock, data latch, serial data, +5v and ground. The SNES signal has more data clock pulses after the data latch pulse but the protocols are the same, otherwise. This means that if you make a pin-to-pin adapter that sends SNES controller signals to an NES port, everything works just fine and the NES will just ignore the extraneous clock pulses.

Now, original NES controllers are getting fairly expensive these days--particularly the "dog bone" controllers that are round instead of pointy--and the third party reproductions from Tomee et al. are pretty universally reviled for being flimsy, unresponsive and altogether crummy. SNES controllers, on the other hand, are more ergonomic, originals are generally more plentiful and some of the repros (like this one) are actually pretty great. I also already have a bunch of SNES controllers, including an ASCII Pad, which is possibly the finest third party controller ever produced...

So, with all of that in mind, I cobbled together an SNES to NES controller adapter (there are a number of guides online, see also: here and here, among others) using a couple of cheap extension cables, specifically Tomee NES extensions (I found a set of 2 from an eBay seller for $9) and "Gen" 2-pack SNES extensions. I'll post which wires I connected, but it seems the factories that produce these extension cables just pick a handful of randomly colored wires when they put them together, so don't assume they'll apply to your own cables in any logical way:

NES side   |   SNES side 

  Yellow  <->  Black 

  Orange  <->  Green 

   Black  <->  Red 

    Blue  <->  Yellow 

   Green  <->  White

Ideally, you would figure out which wire carries which signal using a multimeter but mine is on the fritz, so I just trial-and-errored my way through it, which was a pain in the ass, but whatever. It worked in the end. Interestingly and unexpectedly, NES' B-button becomes the SNES' Y-button, and NES A becomes SNES B, which is really fantastic, since the angle of the SNES B and A buttons would make them hard to press at the same time had the naming/mapping been consistent.