Help adapting the NCR 4950

[consideringquiet]

Okay so the fella from reddit told me to cut the JO jumpers on the board. Ought I do it?

[TheInverseKey]

Okay so the fella from reddit told me to cut the JO jumpers on the board. Ought I do it?

Yeah that is who I got the photos from so I would give it a shot. He seemed quite knowledgeable about this conversion.

[consideringquiet]

Okay so the fella from reddit told me to cut the JO jumpers on the board. Ought I do it?

Yeah that is who I got the photos from so I would give it a shot. He seemed quite knowledgeable about this conversion.

So on the board the JO1 jumper was already cut, but I think there may be some more on the board as another jumper says JO3.

[TheInverseKey]

Okay so the fella from reddit told me to cut the JO jumpers on the board. Ought I do it?

Yeah that is who I got the photos from so I would give it a shot. He seemed quite knowledgeable about this conversion.

So on the board the JO1 jumper was already cut, but I think there may be some more on the board as another jumper says JO3.

I have an update on this board and the information about the jumpers and the voltage regulator. I thought that this board looked familiar and that it was a board that was rebranded for a bunch of other companies that would be using them for their terminals. Well it turned out I was right when I recently purchased an ADDS ASCII and it had all of the jumpers already in place. Now mine didn't come with the voltage regulator so it just take the 5 volts.

Jumpers:
Here is a picture of the jumpers that came on my ADDS ACSII

Spoiler:

Voltage regulator:
I also have a NMB PC 122 with a voltage regulator and this board according to others on the forum needs more than the regular 5 volts. These NMB/Hi-Tek boards needs 9 volts because they are meant for a terminal that would be able to supply it.


Going to be using a teensy to convert this rather than use the cable that came with it because it was not in the greatest condition. Will be reporting back once I have the converter done and or issue/other information that I find.

[TheInverseKey]

Update here is the pinout for converting it after the jumper wires have been put in.

This is based on the at rj11 conncector that came with my board. For a better understanding have a look at the picture of when it is connected to a teensy.
Top
6 = reset - red
5 = data - green
4 = case gnd - black shielded
3 = clock - yellow
2 = sg gnd - black shielded
1 = vcc +5v - white
Bottom

Top is the original cable and the bottom is the teensy cables:

Spoiler:

[consideringquiet]

Well i cut the jumpers and no dice. I suppose this project might be dead in the water for me now. I cant get a teensy in time for college nor do i have the equipment or knowledge to really wire one together.

Any last ditch ideas to deal with the power issue?

[TheInverseKey]

Well i cut the jumpers and no dice. I suppose this project might be dead in the water for me now. I cant get a teensy in time for college nor do i have the equipment or knowledge to really wire one together.

Any last ditch ideas to deal with the power issue?

There is 2 options I think:

Here is something that another user said to use to get the correct voltage. This should bump the voltage to 9v but I would check to see how much is going to the controller before doing anything.
https://www.pololu.com/product/2116

Or you could remove the voltage regulator and see if it works with the normal 5v but there is a bit of difference in the components used between your board and mine. You would have to find all of the missing components that are different to make it work.

[consideringquiet]

Well i cut the jumpers and no dice. I suppose this project might be dead in the water for me now. I cant get a teensy in time for college nor do i have the equipment or knowledge to really wire one together.

Any last ditch ideas to deal with the power issue?

There is 2 options I think:

Here is something that another user said to use to get the correct voltage. This should bump the voltage to 9v but I would check to see how much is going to the controller before doing anything.
https://www.pololu.com/product/2116

Or you could remove the voltage regulator and see if it works with the normal 5v but there is a bit of difference in the components used between your board and mine. You would have to find all of the missing components that are different to make it work.

Thanks! I'll definitely take a look, but also it seems like there was a miscommunication between me and the reddit fella. I was supposed to cut the JA wires and leave the JO alone. I needed to solder the JO jumpers anyway since one was cut and another didn't have a jumper to begin with. so I'll be up to trying that.

If this doesnt work I'll move onto those options. I really hope i can get this working before the end of august!

[consideringquiet]

I'm starting to think I should just delegate these projects to other people... Whenever I touch things like this they just turn to trash. I'm like the Midas of breaking keyboards I swear

The guy off Reddit pointed out that I had the correct wiring, and said I likely fried the board. What do I do now?

[snacksthecat]

[consideringquiet]

Right?

[snacksthecat]

No but really if you desolder the IC on it and replace it with a Teensy++ 2.0, you'd have a fully programmable keyboard. And there's no chance of frying the board because, well, there's nothing to fry!

[consideringquiet]

So, I haven't yet given up this project. The whole wiring a PS/2 cable is out the window, though. I'm considering replacing the IC altogether. However, I'm unsure if my testing on this board borked it all together.

[consideringquiet]

No but really if you desolder the IC on it and replace it with a Teensy++ 2.0, you'd have a fully programmable keyboard. And there's no chance of frying the board because, well, there's nothing to fry!

So, my friend found a pinout for the original IC online. Would we theoretically just match the pins there and go on from there?

Do you have any tips on converting the IC to teensy? It's my first time for this sorta thing.

[consideringquiet]

So I made one last effort to adapt this without completely removing the IC. My friend helped me resolder some shoddy jumpers of mine and remove certain resistors and capacitors to match theinversekeys pcb. After wiring the teensy, we got stuck on the fact that the keyboard would power on, but not send any signals back to the PC. Using HID sense we found that the keyboard would spit out a wEE error and wouldn't be recognized as AT.

My friend tried a whole manner of different pin combinations aside from sgn gnd and vcc, but no dice. We tested the capacitors inboard, one was not putting out anything through the multimeter but replacing it didn't help.

I'll post some photos of the new wire job. I'm thinking I might have to replace an IC, which would be mighty useful.

[consideringquiet]

There's always the possibility I borked this damn thing into a Kentucky fried paperweight when I was feebly attempting to adapt it to PS2 earlier. What should I do now? I thought the pinouts were correct. I don't want this thing going to waste, I got it NOS.

Next best thing I can think is completely desoldering either the IC or PCB.

[consideringquiet]

Bump, still haven't gotten around to replacing the IC since I can't find the original pinout chart online for the chip.

Anybody have any experience with this?

[hackser]

Okay after trying a few things out the mod worked for me. just change out all the jumpers. I had a pcb version with no voltage regulators. My cable looked like a phone cable with 4 conductors and had different color order than consideringquiet's cable. But after the AT conversion, TheInverseKey's pinout worked.