Apple II c repair keyboard and check disk driver error

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Last seen: 2 years 4 months ago
Joined: Jan 7 2022 - 07:00
Posts: 2
Apple II c repair keyboard and check disk driver error

Hi all,

I'm new in this forum and I want to say hello to all and sorry my bad english!

I'm trying to repair an Apple II c computer that was stocked in my house for many years. When I stocked it, like 15 years ago, it works without no problem but few days ago I have reconnected it and I have discovered two big problem:

- First was a strange behaviour of the keyboard: all the special characters like "( ) , ; -_ " and numbers works great but all the other letters don't come on screen (same for the number "5" only): when I press the keyboard button the cursors on screen flicks, so I think something happens... but without letters I can't put any command

- Second problem was that every disc I use, give the message "Check Disk Drive": I have tried many disk, most are Official Apple Disc coming with the PC, other are old games and similar but I have the same result


I have disasseble teh PC, make a faster clean from dust, check the keyboard buttons and cable and all appear ok but first problem remains

For the second problem, I tried to clean the disk reader parts, and also, I have tried to use another disk reader getting it from the extenral drive (I have also the external driver but I can't use it directly because can't put commands to active it) but the result is the same.


Here you can found other image and videos:


How can I do for trying to repair it? I need a new keyboard? Where I can buy it? You think both disk reader are broken or ALL my 5 inches disk are unreadable? Where I can buy a disk that I'm sure it's work to understand if is the disk reader or the 5 inches floppy? Other ideas?


Glad of your help


Last seen: 6 days 23 hours ago
Joined: Apr 26 2016 - 08:36
Posts: 684
I would first remove all the

I would first remove all the socketed chips including the keyboard encoder ship and re-insert them.

This might solve the keyboard problem.

If it doesn't I would check the individual key switches with a continuity tester or ohm-meter to see if they are working.


Also, try booting the computer with the two Apple keys held down (or turn it on with the keyboard disconnected) which will force it to go into self-diagnostic mode.

This might show some RAM issues.



Last seen: 2 years 4 months ago
Joined: Jan 7 2022 - 07:00
Posts: 2
Can you underline what are

Can you underline what are the chips you are talking about maybe with a red circle on the first image?There are other diagnostic command that I can try?

I don't have the correctd tool to remove the sokcet chipset, this is why I do not tried this until now. 


Last seen: 4 days 22 hours ago
Joined: Apr 24 2012 - 17:03
Posts: 273
First of all, where are you

First of all, where are you located? Depending on that you may get stuff easier. Keyboard - sounds like you have the keyboard switch enabled (next to the reset button) and it shows different layout. If keys don't display, you may have to clean the switches, deoxit is the best but also can use some isopropyl alcohol. For the floppy can be a dirty head (clean with q tip and isopropyl alcohol) or bad drive speed.The self test somebody suggested (open apple - close apple - control - reset) may not work if it's a ROM 255, you can check the rom version by typing "PRINT PEEK 64447" but if your keyboard doesn't work, is useless.So try those things, you can also disassemble the external drive and replace it with the internal, maybe that will work.

EDIT - after seen the video seems you are in europe, the keyboard switch could be down, and some keys don't work (you need deoxit). Check some of my videos on restoring and cleaning //c:

Good luck.

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