black plus 2 keyboard fault

[speccypsh]

hi guys
have a problem with a black plus 2 hope you can help with started when i replaced power connector certain keys now dont work 1/2 and enter among others) have taken keyboard apart and completely and cleaned reseated connectors with no joy strange thing when using keyboard check on
retroleum v2 all keys work but while checking through the keys when pressing certain keys 2 keys lights up ie 1 and 2 . also when selecting games from the sd card the enter key works but in the game .do you think the membrane is at fault thanks in advance

[1024MAK]

It may be that the problems with the keyboard existed before you opened the case. Were you able to test it before opening it?

The keyboard uses a membrane, which itself is wired as a matrix of "switches". The "normal" keys (those that are the same as in a rubber key model) use a five by eight matrix. On the black +2A, +2B and +3 models, the rest of the keys are on another matrix on the same membrane.

Can you please list all the non-working keys.

Mark

[speccypsh]

Hi

Thanks for reply keyboard worked before and have done other work on previously recap etc with no probs but keys that dont work are
1,2,9,0,q,w,o,p,a,s,l and enter. but these keys do work when running from within the retroleum smart card as they are used to select the games hope that helps

[1024MAK]

Okay, that's weird...

The keyboard matrix is pure hardware and what program is running shouldn't make any difference to the hardware. Having said that, BASIC and some games will ignore a key if two of the normal keys are detected to be pressed simultaneously. That may explain why the symptoms are different.

Keys 1 Q A [Caps shift] 0 P [Enter] [Space] are one column.
Keys 2 W S Z 9 O L [Symbol shift] are on the next column.

More later, when I'm on my PC.

Mark

[speccypsh]

Hi

Solved it turns out a piece of solder was joining 2 pins together on one of the joystick ports cleared and shes good as new but thanks for the response

[oO cozy Oo]

Thanks for letting us know

[1024MAK]

And if course, the joystick ports are part of the same matrix...

Glad you found the problem

Mark