Keyboard not work on 520ste

[FLYNC1]

Hello all !!!

Could somebody advise me about the keyboard not working or maybe I did something wrong?

A story about my 520 Ste I'm a newbie but know a little about electronics.

So when I turn on the computer desktop shows up, but no one's keys not respond, original atari mouse moves only up, down, and left, so with the mouse I can pop up menus on the desktop. I found somewhere on the internet it is possible to be chip SN74LS244N broken, I ordered a new and replaced chip. but it not
helped :(

Thank you

[exxos]

Do your hear any clicks in the audio when any keys are pressed ?

[alexh]

It is extremely common for the mouse/joystick ports to break due to the strange design and forces required to insert and remove joystick/mouse. They can usually be diagnosed visually and fixed by simply reflowing the solder where the connectors meet the PCB.

[rubber_jonnie]

Aside from what alexh has already said about the mouse/joystick ports, i'd suggest checking all the wires that go to the keyboard connector on the mainboard and make sure with a multimeter that they all have continuity.

I'd also suggest a check of the keyboard PCB to be sure that there are no other bad solder joints or cracked PCB traces and that the microcontroller is properly seated (It's usually socketed) and that it is getting power.

You may also want to check continuity to the 6850 from the keyboard connector as per the diagram below:

Screenshot 2022-11-18 at 09.30.49.png

As well as all the other connections for the keyboard connector.

BTW if you hold down the 'Alt' key along with the cursor keys, it should move the mouse pointer. If you're at the desktop then most keys don't do much without holding down CTRL or some other modifier like ALT.

To test properly you need some sort of text editor to type into or a diag cart to see what the keys are doing.

[DoG]

Since mouse is working you probably have 5V, GND, TX and RX lines working to the keyboard through the cables at least (GND is however two wires). Since TX and RX are working, the big chip on keyboard must be somewhat working and the MC6850 as well.

So some traces, as suggested above, might be damaged.

[FLYNC1]

Thank you for your advice.
I hold down the 'Alt' key along with the cursor keys, and it moves the mouse pointer.

so I think the keyboard works, but the mouse only moved in 3 directions up down and left ). and I've already checked the mouse connector and resolder it, I think maybe just the mouse is broken.

is it possible to connect ps/2 mouse to the atari? I mean electrically, just cut cable and solder cable from ps/2 mouse to the atari connector?

[rubber_jonnie]

Thank you for your advice.
I hold down the 'Alt' key along with the cursor keys, and it moves the mouse pointer.

so I think the keyboard works, but the mouse only moved in 3 directions up down and left ). and I've already checked the mouse connector and resolder it, I think maybe just the mouse is broken.

is it possible to connect ps/2 mouse to the atari? I mean electrically, just cut cable and solder cable from ps/2 mouse to the atari connector?

The protocols used by Atari and that of PS/2 are different, so you cant just connect another mouse to the Atari cable, but there are adaptors (Search Atari mouse adaptor on eBay) that will take PS/2 mice with either the round connector or USB that plug into the Atari 9 pin mouse socket.

What is a common scenario is that the Atari mouse cable fails internally, so in all likelihood the mouse is good but the cable is not. You could make a new cable if you have the pinouts at either end of the cable.

I'd urge you to get a text editor like Everest to load up and test the rest of the keyboard, you'll be able to use the alt+cursor keys to navigate to the A: drive and the Insert key as the left button.

Load up the text editor and create a new document then test each key.

[FLYNC1]

Hi all, today I finally received my GoTEK v.3.37.
from mistakes and tries, I launched "Word plus" and tested the keyboard, with no problem.

Also, I found out why mouse works only in a few directions because one metal roller was dirty and slippery, so I cleaned the rollers with alcohol.
After this mouse works fine.

Thank you everybody for your help and advice.

P.S. going to find answers about GoTEK :roll: