I've got 2 RetroUSB RetroKit chips to solder onto the front ports of the NES - each port needs to connect 5 pins/wires to the chip. I prepared the wires on the back of the port already by removing them from the original NES board, cutting the wires a little shorter, and stripping the ends. The wiring diagram (and order form) for the RetroKit can be found here, but I'll post it here too so it's easier to see.
Normally the RetroKit's are meant to be inside a standard NES controller, converting the pad itself into a usb nes controller - but because I want to use the original ports on the front I'll be putting the RetroKit on the port instead of inside the pad.
The RetroKit and a NES controller port (once removed from the case) are below.
My main concern is that the wire colours on the back of the port might not match the colours inside the pad. If the wiring colours didn't match then we'd have issues with the wrong leads soldered to the wrong contacts. I couldn't find an answer online whether the internal wire colours matched the pads. Unfortunately I don't have a multi-meter at home to just check that either (I know, the shame!!). In the end, I just took the gamble and soldered one to see what happens.
Once soldered on I just wanted to confirm it worked - so I plugged the USB lead into my laptop, and after a few seconds it had registered as a pad. Great - so the RetroKit itself works. :) So next I plugged in a NES pad into the port, loaded up the controller settings in Windows 7... annnnd nothing. Bugger!!
The soldering looked correct, and while the NES did come to me as faulty the port itself looked undamaged. I decided it must be the controller (it is a Chinese replica pad I'd bought off eBay for about £1.50). Luckily I had a couple of original pads that was donated to me by a nice person at work, so I dug one out and plugged that in... it worked! Phew!!
After some checking, all the controller buttons were working in the controller setup tool in Windows, so my soldering is fine. I'll add some pictures below showing me trying the D pad and some buttons.
I soldered the other RetroKit to the second controller port, tested the port again with the same pad. Once I was happy both were working as expected I then added them back into the box.
I don't want to have the chips just loose in the case, it'll put pressure on the solder points and could potentially damage the RetroKits if they're just banging around lose in there. To fix them into place I added some velcro stickers to the top of the main chip on the RetroKits, and the other side to this on a section of case near the ports.
This will hopefully keep them fixed in place, but also lets me move them around if needed. I've fed the excess USB wiring under the cartridge loader for now, if it bothers me I may shorten the cable so everything is nice and neat..
So the current state of the NES looks like this:
What's next?
After this, we've got:
- The back panel - I need to add in the USB port for power in, and HDMI for video out.
- The power/reset circuit to install, and configure the setup script for handling that on the Pi
- The Pi itself.
