Restoration Tips for a Panasonic KX-D4910D?

PixelPlays · 27 Jan 2021, 21:04

I recently found the stated KX-D4910D with Alps SKCC Creams at a thrift store for twenty dollars, with its original carry-case/handle thing, cables, and some of the documentation. With this being the first vintage that I've ever tried, it OBVIOUSLY blows any of the linears I've owned up to this point out of the water (even with it being dirty as it is), so I'd love to be able to convert it to USB and use it with my PC.

It uses an EIA RS232 25-pin connector (I'm still not sure if EIA is the actual protocol, or just something pertaining to the design of the connector, as vintage terminal keyboards are not something I am well versed in). I'm fairly certain that its internal PSU is shot (I got it to power up once, but now it won't again). Most of the switches feel fine, if a bit stiff since the SKCC Creams actuate at the same force as my daily driver switches bottom out at. Still, just doing some random typing on it feel s extremely satisfying and I'd love to get it working over USB, or at least working so I can use it with its built in thermal printer as an electronic typewriter of sorts.

But as I said, vintage keyboards are not something I know anything about, so I have no idea what direction to turn to as far as restoration or conversion goes. Any help would be greatly appreciated! I made this Deskthority account just to try and learn more about my find, and maybe even get it working again! Thanks again for reading.

Edit: I attached a picture, with my daily driver sitting on top of it as a size comparison.

headphone_jack · 27 Jan 2021, 21:56

While the process is a bit different for SKCC (you have to desolder them to open them) this video is a very good tutorial made by a forum member that helped me a lot when I was first starting out: https://www.youtube.com/watch?v=RnvC80Vjuts&t=59s

As for conversion, with SKCC it should be as simple as mapping the matrix, if you don't want to try reverse engineering the original protocol. I am kind of inexperienced with this process, but I'm sure that many others with more knowledge on this should be able to help you out. Good luck, and nice find!

PixelPlays · 28 Jan 2021, 00:19

headphone_jack wrote: 27 Jan 2021, 21:56 While the process is a bit different for SKCC (you have to desolder them to open them) this video is a very good tutorial made by a forum member that helped me a lot when I was first starting out: https://www.youtube.com/watch?v=RnvC80Vjuts&t=59s

As for conversion, with SKCC it should be as simple as mapping the matrix, if you don't want to try reverse engineering the original protocol. I am kind of inexperienced with this process, but I'm sure that many others with more knowledge on this should be able to help you out. Good luck, and nice find!

My first instinct was to message Chyros about it, since I already watch his videos. It was actually off the back of what I've learned from him that I was able to recognize the switches as Alps SKCC! He told me to just post in the forum itself as conversion and total restoration isn't his field of expertise.

zrrion · 28 Jan 2021, 00:44

if the switches are clean and feel smooth the only real reason to open them up would be to swap the springs. Personally I find SKCC is easier to open than SKCM, so that is a plus. I need to make a video to demonstrate the opening process as it really is not that difficult.

As for getting the thing converted to USB that depends on how the thing is wired up. Some electric typewriters do not have any brains on the keyboard itself. If that is the case for yours then all you would need to do to convert it would be to detach the cable that runs between the keyboard and the main board and map out the matrix. After you have the matrix mapped out you would then be able to make QMK firmware for it.
If it has the brains on the same board then you would have to brain it or hand wire it, which are a bit more involved.

PixelPlays · 28 Jan 2021, 01:08

zrrion wrote: 28 Jan 2021, 00:44 if the switches are clean and feel smooth the only real reason to open them up would be to swap the springs. Personally I find SKCC is easier to open than SKCM, so that is a plus. I need to make a video to demonstrate the opening process as it really is not that difficult.

As for getting the thing converted to USB that depends on how the thing is wired up. Some electric typewriters do not have any brains on the keyboard itself. If that is the case for yours then all you would need to do to convert it would be to detach the cable that runs between the keyboard and the main board and map out the matrix. After you have the matrix mapped out you would then be able to make QMK firmware for it.
If it has the brains on the same board then you would have to brain it or hand wire it, which are a bit more involved.

Some of the switches definitely feel like they could use a good cleaning, but most of them feel smooth but stiff. As I said, the switches are heavy for me.

I'm not sure if it has any brains or not, since I know it's made to connect to a terminal. But it also has a built in thermal printer, so I'm not really sure.

MMcM · 28 Jan 2021, 01:51

PixelPlays wrote: 28 Jan 2021, 01:08 I'm not sure if it has any brains or not, since I know it's made to connect to a terminal. But it also has a built in thermal printer, so I'm not really sure.

Have you opened it up yet? If so, can you post some pictures of the inside? Somebody might be able to tell from looking.

PixelPlays · 28 Jan 2021, 04:31

MMcM wrote: 28 Jan 2021, 01:51
PixelPlays wrote: 28 Jan 2021, 01:08 I'm not sure if it has any brains or not, since I know it's made to connect to a terminal. But it also has a built in thermal printer, so I'm not really sure.
Have you opened it up yet? If so, can you post some pictures of the inside? Somebody might be able to tell from looking.

I actually just got it opened and liberated the plate and PCB! I'll take some pictures and post them here. The keyboard PCB attaches to the other one pictured via that white ribbon cable. Looks like there's a lot going on here.

PixelPlays · 28 Jan 2021, 04:35

Looking at the back of the PCB, it doesn't look like the keyboard itself has any brains.

PixelPlays · 29 Jan 2021, 05:08

zrrion wrote: 28 Jan 2021, 00:44 if the switches are clean and feel smooth the only real reason to open them up would be to swap the springs. Personally I find SKCC is easier to open than SKCM, so that is a plus. I need to make a video to demonstrate the opening process as it really is not that difficult.

As for getting the thing converted to USB that depends on how the thing is wired up. Some electric typewriters do not have any brains on the keyboard itself. If that is the case for yours then all you would need to do to convert it would be to detach the cable that runs between the keyboard and the main board and map out the matrix. After you have the matrix mapped out you would then be able to make QMK firmware for it.
If it has the brains on the same board then you would have to brain it or hand wire it, which are a bit more involved.

So after a bit of looking, this board doesn't have any brains on it. I'm fairly certain the keyboard's matrix is either 8*8 or 9*7. I have a multimeter arriving tomorrow.

After I have the matrix mapped, where do I go from there? I know Soarer's converters were made using Teensys, but I have no clue how those work. Do you know where I should go from there, or someone that might? Thanks!

zrrion · 29 Jan 2021, 06:04

For firmware the easiest way would be to build it with https://kbfirmware.com/

PixelPlays · 29 Jan 2021, 06:07

zrrion wrote: 29 Jan 2021, 06:04 For firmware the easiest way would be to build it with https://kbfirmware.com/

Thanks for this tip! But as far as actually getting the ribbon cable running into USB and the actual brains of the conversion, how do I go about that?

zrrion · 29 Jan 2021, 09:32

on the cable that comes out of the keyboard each of the wires goes to either a row or a column (the exception is for the 2 wires that go to the LED). You will need to connect all of those wires to the pins of a teensey. Once they are connected you will need to figure out which pins are rows and which pins are columns (a multimeter is helpful here). With that established you would need determine how the physical keys map to the logical matrix. With that information you set up kbfirmware and it should give you a .hex file to flash onto your teensey. If everything went right you should be able to start typing

PixelPlays · 31 Jan 2021, 04:11

zrrion wrote: 29 Jan 2021, 09:32 on the cable that comes out of the keyboard each of the wires goes to either a row or a column (the exception is for the 2 wires that go to the LED). You will need to connect all of those wires to the pins of a teensey. Once they are connected you will need to figure out which pins are rows and which pins are columns (a multimeter is helpful here). With that established you would need determine how the physical keys map to the logical matrix. With that information you set up kbfirmware and it should give you a .hex file to flash onto your teensey. If everything went right you should be able to start typing

I've got the matrix mapped out
The columns correspond to that bank of eight diodes, but the modifiers have their own diodes that lead to those same points

AppleRingo · 20 Nov 2022, 06:34

Hi PixelPlays, I recently got a Panasonic KX-D4910D, but I can't find a manual anywhere. I will be very grateful if you can send me a copy of manual in pdf.