Help with Apple II Keyboard screen characters

6 posts / 0 new
Last post
Offline
Last seen: 3 weeks 2 days ago
Joined: Dec 21 2013 - 20:49
Posts: 62
Help with Apple II Keyboard screen characters
AttachmentSize
Image icon 1st row41.54 KB
Image icon 2nd row38.54 KB
Image icon 3rd row39.43 KB
Image icon 4th row44.69 KB

I am trying to get an Datanetics keyboard working with my Apple II computer. I am getting a mix of different character outputs on the screen when I type each key on the keyboard. Some keys give the proper output, some give no output and some give the wrong character for the key that was pressed. I would like to know if anyone has had a similar experience. I am going to try the following: 1) try the keyboard in my other older original Apple II that is working fine, 2) clean each key (remove cap, spray contact cleaner in the key assembly, work the key up and down). Any other suggestions?

 

Offline
Last seen: 1 week 1 day ago
Joined: Jul 5 2016 - 19:01
Posts: 49
I would say the NO are faulty

I would say the NO are faulty key switches.  Some of these may be fixed with contact cleaner.  When that doesn't work, I’ve opened them up but it can be tricky as they are sealed.Where the output is different from the key you pressed it could be the keyboard encoder.Cheers

Offline
Last seen: 3 months 2 weeks ago
Joined: Mar 31 2020 - 19:55
Posts: 848
You could have switches that

You could have switches that are in a connected or partly shorted position, that are thus tricking the matrix into displaying the wrong character. I have the same Datanetics mechanism with similar woes.

 

I have yet to find an authoritative source on restoring existing DC-50 switches. 

 

Should you give up on this and replace it as a whole at any point, send me a note as I could use it for spares. 

Likewise, if you find a good solution to restoring the mechanism that does not involve buying new or reproduced switches, please post it. 

 

What is the serial number of your ][ ?

macnoyd's picture
Offline
Last seen: 4 hours 39 min ago
Joined: Oct 15 2012 - 08:59
Posts: 764
Insure that the data lines

Insure that the data lines from the keyboard are connected in the proper order.

If you have one swapped with another, you would get this affect.

Check the data lines from the keyboard to the A][ socket.

 

You might want to note the ASCII values on the screen, then

compare them to the ASCII values expected.  This could lead you right to it.

Just a suggestion...

Offline
Last seen: 3 months 2 weeks ago
Joined: Mar 31 2020 - 19:55
Posts: 848
macnoyd wrote:Insure that the
macnoyd wrote:

Insure that the data lines from the keyboard are connected in the proper order.

If you have one swapped with another, you would get this affect.

Check the data lines from the keyboard to the A][ socket.

 

You might want to note the ASCII values on the screen, then

compare them to the ASCII values expected.  This could lead you right to it.

Just a suggestion...

 

That, too, aye. 

It is one of the following:

 

Faulty encoder.

Imporoperly connected.

Matrix corrupted by bad keyswitches.

Bad capacitors. 

 

Offline
Last seen: 3 weeks 2 days ago
Joined: Dec 21 2013 - 20:49
Posts: 62
Switched to a spare keyboard - got to a better state

I  decided to try a spare keyboard I had in a box in the garage. It is missing the '1' and '2' key switches. When I installed the keyboard  the only key that worked was the RESET key  (that is proabably why it was in a box in the garage). I decided to see if a new keyboard encoder MM5740AAE/N that I had ordered on eBay would help. This improved things a bit. I had a few keys working in all the rows except the first row. I went through the process of fixing the keys in the 2nd, 3rd, and 4th rows that did not produce a character on the screen when pressed. I removed the key cap and sprayed contact cleaner into the key switch base where it meets the white key stem. I worked the stem up and down a few times and was able to get all keys to work -- except the top row keys. I could not get any of the top row number keys to work. I think this may be due to the missing key switches at the  '1' and '2' key positions. I'm going to swap key switches from the original keyboard to the '1' and '2' keys of  'spare' keyboard and see if makes the other number keys work. 

The serial number of the Apple II that I am working on is 14215. 

Log in or register to post comments