A600 keyboard trouble

[psygnosis]

hi all ive recently stripped and refurbed a battered old 600

i even stripped the keyboard and cleaned the membrane,and when i put everything back together when i press the shift and : key i get a load of letters in capitals all at once.


also if i do the same with the ? key i get another load of letters in capitals,and if i don't press shift i still get the same letters but not in capitals.


i only found out the problem when trying to load stuff prom the command prompt of whdload.......ive also tried this in "say" on workbench and it does the same.

ohh also key number 9 also gives me a load of numbers from 9-1 backwards when pressed

ive recently installed a cf 4g flash card and 8 meg fast ram but im assuming it may be something to do with me cleaning the keyboard membrane

any clues people?

[Allen1]

I don't know what you used to clean the membrane but maybe there is some residue left causing a short between each row of keys ???

Also another possibility, are the 2 SMD capacitors behind the keyboard connector on the motherboard OK. Maybe they have leaked and caused this reaction by shorting out the connections etc for the keyboard, its not very likely but worth a look as well as checking for anything else that may have been spilled on the motherboard.

Good luck with finding the fault, it would be very handy if you could get hold of a working keyboard to see if the problem is still there when it is used as it would narrow down the search.

[psygnosis]

Originally Posted by Allen1

I don't know what you used to clean the membrane but maybe there is some residue left causing a short between each row of keys ???

Also another possibility, are the 2 SMD capacitors behind the keyboard connector on the motherboard OK. Maybe they have leaked and caused this reaction by shorting out the connections etc for the keyboard, its not very likely but worth a look as well as checking for anything else that may have been spilled on the motherboard.

Good luck with finding the fault, it would be very handy if you could get hold of a working keyboard to see if the problem is still there when it is used as it would narrow down the search.

cheers mate yehh them caps seem fine,i have another 600 ill try the keyboard in that and if i get the same problem i know its not the keyboard

[jimbob]

Have a look at the keyboard matrix schematic on here for some clues-

http://www.amigawiki.org/dnl/schematics/A600_R1.5.pdf

At first look, the right shift key is in between the dodgy "L" and "M" rows so maybe a short between pins 5, 6 & 7 at the connector.

Doesn't explain the 9 row though, or why all columns are triggered by one key press. Is it only one key in the faulty rows which causes this? Is it only one shift key or both, what about the other special keys, ctrl, alts and amigas? Ctrl-A-A works ok?

[psygnosis]

Originally Posted by jimbob

Have a look at the keyboard matrix schematic on here for some clues-

http://www.amigawiki.org/dnl/schematics/A600_R1.5.pdf

At first look, the right shift key is in between the dodgy "L" and "M" rows so maybe a short between pins 5, 6 & 7 at the connector.

Doesn't explain the 9 row though, or why all columns are triggered by one key press. Is it only one key in the faulty rows which causes this? Is it only one shift key or both, what about the other special keys, ctrl, alts and amigas? Ctrl-A-A works ok?

mate that fantastic thanks for taking the time out

[psygnosis]

installed a new keyboard and it worked fine so it must have been the membrane

cheers

[jimbob]

Glad you got it fixed. A600 keyboards are a constant pain, If you still have your broken one, may I point you in this direction -

http://www.amibay.com/showthread.php...204#post482204

Rwap, is looking into getting replacement membranes made for various amiga keyboards but needs a sample of A600.