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Vt102 without a keyboard

S

silver2k

Member
Joined
Feb 13, 2023
Messages
22
Hi everyone

I picked up a vt102 from eBay that would not power on. I opened it up, cleaned it out and inspected everything.

I may have got lucky as the fuse holder was cracked and the fuse broken.

FYI if you need to replace it, the one below is nearly identical. You will need to solder one wire on (or add a crimp connector) as one lead is soldered on the OEM one. The other is just a crimp terminal connector which fits the new one. The fuse for 110 is a 1.25A


Now I have the vt102 turning on and I get a fairly clear picture with no burn in.

IMG_1117.jpeg
IMG_1116.jpeg

On the screen there is a flashing 4…which reading the technical manual appears to be a keyboard error - this makes sense as I do not have a keyboard.

Before I go on what is likely a very expensive hunt for a keyboard, can anyone confirm that this is indeed what it looks like with a keyboard unplugged?

Also any leads on a replacement keyboard would be appreciated, even if homebrew or non-authentic. I took a look online and it looks like someone converted one to usb, however the website with the actual info is now dead. Reading the tech manual, it seems possible to emulate (which is why I was hoping to see the code of the usb one) but this is a bit over my head. If it was a simple rs-232 protocol I do that with a pico and a max232 - but having a combined transit/receive line in addition to an integrated clock signal is a lot to digest.
 
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I have a VT102 (even though it reports on start up VT 125 OK in the middle - so not sure why). I get a blinking cursor with the keyboard plugged in. And a blinking 4 just like you do with no keyboard plugged in.
 
tradde said:
I have a VT102 (even though it reports on start up VT 125 OK in the middle - so not sure why). I get a blinking cursor with the keyboard plugged in. And a blinking 4 just like you do with no keyboard plugged in.
Click to expand...
Does it say VT102 on the label at the back? I have a VT125 (Upgraded from VT100) and a VT102. The 102 is a much more cut down machine, missing some of the slots to upgrade it. If it's saying VT125 on power up, I'm guessing the internals have been upgraded or the lid/badge swapped.

The VT125 is rather nice as it has graphics capability using Regis.

Can also confirm that my units also display a blinking 4 with keyboard unplugged.
 
there is also a project that will allow you to use an arduino to connect a standard USB keyboard, i find that the VT100 keyboard can be a little hard on my wrists during longer sessions: https://github.com/ryu10/usbkbdshield_vt100

of course i would always recommend having an original keyboard for completeness, but the keys can be a bit heavy and scratchy :)
 
This was given to me so I really don't know what it is. I had assumed from the front it was a VT-102 as that's wha the label there says. On the back it says VT-100-NA.
But on the back there are two boards sticking out. One has 2 RCA connectors and one has 3. So I assume it has some graphics capability. Then when powered on in the middle it displays VT-125 OK. I have to guess you are correct that someone upgraded this. The bottom plastic case is not the same color as the top plastic. So maybe the original was broken? And this was lying around. I can't say. I have never used it, but it seems to work fine.
 
@tradde - thank you for the confirmation!


@hush -- thank you so much that is exactly what I was hoping for! I tried searching but when you start typing in emulate and vt100 you start getting vt100 terminal emulation instead.

I ordered the parts and the custom pcb from JLCPCB to put one together.
The LM393N that is specified in the BoM is obsolete. I was able to find a suitable LM393N from a different manufacturer on ebay
The LED display was also obsolete or no longer available. I used this one:
The USB shield that is specified is also obsolete (and the link goes to a spam page.) These seemed fairly generic so I ordered one off of aliexpress from another no name manufacturer.

I have an old IBM model M that would be a perfect fit...if only it was USB. I'll give it a shot with an adapter but I am doubtful.
 
tradde said:
This was given to me so I really don't know what it is. I had assumed from the front it was a VT-102 as that's wha the label there says. On the back it says VT-100-NA.
But on the back there are two boards sticking out. One has 2 RCA connectors and one has 3. So I assume it has some graphics capability. Then when powered on in the middle it displays VT-125 OK. I have to guess you are correct that someone upgraded this. The bottom plastic case is not the same color as the top plastic. So maybe the original was broken? And this was lying around. I can't say. I have never used it, but it seems to work fine.
Click to expand...
Yep, sounds just like the one I have here. VT100 that has been upgraded to VT125. The graphics capability is pretty nice.

Cheers,
Dave
 
Interesting. I'd have never known this was not a VT-102 with some extra boards stuck in. I'll have to try to find info on what can connect to it. It the one with two RCA jacks maybe mono and the 3 color? I have no idea.
Edit: I see it can not support color. But does have graphics. I'll have to see if I can find something to connect to it.
 
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silver2k said:
@tradde - thank you for the confirmation!


@hush -- thank you so much that is exactly what I was hoping for! I tried searching but when you start typing in emulate and vt100 you start getting vt100 terminal emulation instead.

I ordered the parts and the custom pcb from JLCPCB to put one together.
The LM393N that is specified in the BoM is obsolete. I was able to find a suitable LM393N from a different manufacturer on ebay
The LED display was also obsolete or no longer available. I used this one:
The USB shield that is specified is also obsolete (and the link goes to a spam page.) These seemed fairly generic so I ordered one off of aliexpress from another no name manufacturer.

I have an old IBM model M that would be a perfect fit...if only it was USB. I'll give it a shot with an adapter but I am doubtful.
Click to expand...
i have had good luck with soarer's converters although the configuration syntax can be a bit strange, i recently purchased one of these which is the same but using VIAL/QMK firmware so that it can be configured via a web browser, so that's how i'm currently using my M122 :) https://www.ebay.com/itm/303905082985

i will note it comes from the philippines so shipping might take a little while, but it's a very useful little piece of hardware, should work just fine with a VT10x once you have it configured
 
I will start looking at these two documents a bit later. Downloaded both. Thanks.
 
hush said:
there is also a project that will allow you to use an arduino to connect a standard USB keyboard, i find that the VT100 keyboard can be a little hard on my wrists during longer sessions: https://github.com/ryu10/usbkbdshield_vt100
Click to expand...

Cool! Do you know if there is an equivalent project for an LK201 keyboard/mouse? I've thought about making the same thing using a Raspberry Pi, but have been sidetracked on other projects (sigh)

CW
 
So could this upgraded VT-102 be connected to a Rainbow or Pro-350? I have the correct color cable that is currently connecting the VR-241 to the Pro-350. Just curious as I believe my Rainbow-100 has the graphics card, but a mono display.
 
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