Recent content by RingingResonance

I don't have a pinout of the cable, but I do have a schematic of the cable adapter. With this, you should be able to use the pinout of the TRS-80 to come up with a pinout for the printer.

I wonder what internal registers it has.

Swap video boards with the working one to see if the CRT is any good? Is the CRT heater glowing? Is there any blue glow in the neck of the CRT? If there is a blue glow then it's gassed and you need a new tube. Be cautious of high voltages!

I'm in the processes of restoring a TRS-80 model 4 gate array and have located one of the problems causing the system to hang at startup and only show garbage on the screen. The FDC timing chips is dead and sends a hold signal to the CPU which was also bad along with the ROM chips. I can make...

I've gotten the USB host adapter for the arduino in the mail and got it all working. I had to do some more tinkering with the code to make the DT80 happy with input. One of the things I had to change was the key mapping. It's completely different! Afterwards though, I got everything except...

I think this is the same kind of paper. https://www.bladegood.fun/product/Silverno-890-2b-060-Recording-Metalized-Paper-pack-Of-5_e6gpnprtsmouotr.html

WOW. Talk about an improvement! Still got some blank spots though. I gotta figure that out.

Yeah, it's supposed to have some random stuff I had on the screen + 'HELLO WORLD' Here's some more pictures I did after fixing a few other small problems and adjusting the head using the "ABCABCABC" method. It seems to not make the very best contact with the wheel and the fingers might be...

It makes no since to me based on what I know about the pinout, the pinout posted above, and the way the printer beeps out with the meter, but it's working somewhat now. Somehow...

I finally got some time + energy at the same time today to play with this some more. After sitting down with the TRS-80 pin diagrams, some tea, and a soldering iron, I tried another new configuration to no avail. This configure made sense on paper and ohm meter probe, but the TRS-80 would fail...

Well, looks like I will be partly or completely reverse engineering the circuit board of the printer to get a schematic and thus a pinout.

So what you're saying is that I had it right before swapping pairs and that there is something else wrong?

Well, I thought I was on to something with that, but I just got done swapping every pair and after checking for shorts and continuity the TRS-80 only shows garbage if the cable is connected even with the printer disconnected.

I've made the adapter cable and have been testing + debugging this thing these past few weeks on and off. Mostly on weekends when I have the time. Today in particular I've been working on it a lot. I've pulled and tested nearly every chip on the board, which is something I really don't like...

I got the emulator to work (without it's USB host adapter, I disabled that code for now until one arrives in the mail). Here's what I had to do. First off, after some probing, I had accidentally grounded the signal line in my connector during assembly so I wasn't getting any data through. After...