deskthority

Specifically, a 1983 1801449.

So, I bought an Elite-C, because it has USB-C and the USB connector is a bit more robust than something you'd find on a Teensy or Pro Micro. I later found out that I could install QMK on it, so I did and tested with a breadboard with a 5pin DIN socket (so, original cable connects to the socket, which is connected to the Elite-C). Works great.

I then soldered the Elite-C to a perma-proto board and connected the wires and pull-up resistors. Time for a test! I press a key on the Model F and rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr. I checked my famously average soldering and tried again. It's working! It's working! It ... stopped working. I double-check the grounding wire on the cable that's connected to the case. Looks OK, but I'll file it a bit. Maybe there's some oxidation on the connector. This time, no worky at all. I shut down and disconnected everything from my computer other than a mouse and the Elite-C and power back up. It works! It works! It's typing rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr;;;;;;;;;;;;;;;;;;;;;;

Yay.

I'm thinking that this could be a grounding problem, but I'm not sure where to check. As mentioned, the ground "line" from the cable to the case looks fine. I've quadruple-checked that the GND from the PCB to the cable, to the socket, to the PCB has continuity.

Your Amazon link no worky either. You mean one of these? If it weren’t as pricey I’d probably jump on it, as I could surely use another AT Soarer box.

As for your problem (instead of mine!) I guess you’re talking about an internal converter for your XT? This thread needs pics of your handiwork. You’re probably right that it’s the grounding, which bit me when I Pro Microed my AT years back, which ultimately fried the Pro Micro. I fixed that with an Xwhatsit controller. Not something so easily done on an XT though.

Hmmm. The links worky for me. A UK thing, maybe?

It's all external. No changes to the keyboard or keyboard cable. I haven't even started restoring the keyboard, as I've been waiting for a foam cut-out, which was much easier for me to buy than do myself.

I'll post some pics in a few minutes. Y'all can then point and laugh. I can take it .

The pics.
* 1553 shows two black shrink-wrapped things. Those are 1K Ohm resistors from VCC to Data and Clock.
* Yellow cable is for reset (not used on this Model F XT, but I soldered it in anyway).
* 1552 has a dollop of solder that looks like it's touching both columns 11 and 12. It's not. Hard to convey 3D-ness.
* Yes, this is way uglier in close ups than I thought it'd be. It's a prototype. I'm old. I use a 5K magnifying lamp.