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Old 21 October 2008, 19:20   #1
AmigaJules
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Fixing A1200 keyboard cable

I'm trying the solution posted by TheCorfiot here: http://eab.abime.net/album.php?albumid=45&pictureid=254

to fix an intermittent qwerty row on my A1200.

I have plenty of cable to work with, since it's never been cut down.

I can get the sticky green sheet to lift, but it leaves behind green stuff covering the tracks on the cable. Any tips on how to remove this? Can I carefully scratch it off with the tip of an xacto knife? I'm afraid to remove too much material. Any recommended solvents?
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Old 21 October 2008, 19:45   #2
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remove the green plastic using any tool like a knife.....scrape it if you can't lift off
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Old 21 October 2008, 19:55   #3
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Try it as is. As it clamps the cable, it may clamp through the glue and make contact.

I tried scraping the glue away, and ended up killing it, .
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Old 21 October 2008, 23:35   #4
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No luck...

After the first attempt, not even caps lock worked. Trimmed off a tiny bit more & ever so carefully scraped off the green - checking my work frequently with a magnifying glass.

Added a piece of tape to the back hoping to thicken the cable enough that the clamp would push it thoroughly into the contacts.

Keys that still don't work:
Tab, whole QWERTY row, Enter, Ctrl (I think), Both shift keys, Left cursor key

All of the other keys seem to work fine.

Questions

Should I be looking at other components on the board? Or does this sound like a case for keyboard replacement? - (I guess one way to test whether the ribbon cable is making a good connection is to take the keyboard apart, connect the cable to the mobo and check continuity between keypads and mobo pins)

If I buy a UK keyboard, can I just swap the keycaps? Doesn't seem to be any circuitry inside the keyboard itself, so this should work, correct?

Is there any (SIMPLE) way to add a keyboard connector for an A2000 or A3000 keyboard?
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Old 22 October 2008, 00:46   #5
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Quote:
Originally Posted by AmigaJules View Post
No luck...

After the first attempt, not even caps lock worked. Trimmed off a tiny bit more & ever so carefully scraped off the green - checking my work frequently with a magnifying glass.

Added a piece of tape to the back hoping to thicken the cable enough that the clamp would push it thoroughly into the contacts.

Keys that still don't work:
Tab, whole QWERTY row, Enter, Ctrl (I think), Both shift keys, Left cursor key

All of the other keys seem to work fine.

Questions

Should I be looking at other components on the board? Or does this sound like a case for keyboard replacement? - (I guess one way to test whether the ribbon cable is making a good connection is to take the keyboard apart, connect the cable to the mobo and check continuity between keypads and mobo pins)

If I buy a UK keyboard, can I just swap the keycaps? Doesn't seem to be any circuitry inside the keyboard itself, so this should work, correct?

Is there any (SIMPLE) way to add a keyboard connector for an A2000 or A3000 keyboard?
Ask Amigakit.com. I had same problem, checked their site and saw that they didnt have any A600 keyboards. So I emailed them asking if they had a keyboard membrane. They replied saying yes they had some.
Saved me buying a whole new keyboard.

Also, think you misunderstood. You werent supposed to remove the whole plastic. I cut down the gaps so far, then lifted each piece and it pulled off easy.
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Old 22 October 2008, 01:11   #6
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Quote:
Originally Posted by FOL View Post
Ask Amigakit.com. I had same problem, checked their site and saw that they didnt have any A600 keyboards. So I emailed them asking if they had a keyboard membrane. They replied saying yes they had some.
Saved me buying a whole new keyboard.

Also, think you misunderstood. You werent supposed to remove the whole plastic. I cut down the gaps so far, then lifted each piece and it pulled off easy.
Thanks for the tip on amigakit. I may check that out.

RE: the repair method - I think I'm doing it correctly. The issue is that even when I lift the "sticky tape" covering the traces on the ribbon, the tape comes off, but there's still a covering of green stuff on the traces. A VERY light scraping with the point of an xacto knife and this stuff flakes off revealing the silver contact layer underneath. I added a piece of tape on the back to "thicken" it a bit since the original carbon connectors seemed SLIGHTLY thicker than just bare traces. Hope that explains my method better - after working on it for several hours, I'm slightly under the influence of tequila... where's that beer guzzling smilie that rkauer always uses in his posts...
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Old 23 October 2008, 17:24   #7
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One last update on this.

I discovered (accidentally) that putting some regular scotch tape on the green stuff, letting it sit for an hour, then removing it takes the green stuff right off. So I have nice clean traces on the ribbon now. Cut a fresh square end on it and plugged it in. Still have intermittent QWERTY row (i can make it work by flexing the connector away from the motherboard) but no ctrl or shift keys.

I'm negotiating a new A1200 keyboard on amibay and hope that the keyboard connector on the motherboard isn't the problem.

Fingers crossed...
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Old 23 October 2008, 19:32   #8
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Quote:
Originally Posted by AmigaJules View Post
One last update on this.

I discovered (accidentally) that putting some regular scotch tape on the green stuff, letting it sit for an hour, then removing it takes the green stuff right off. So I have nice clean traces on the ribbon now. Cut a fresh square end on it and plugged it in. Still have intermittent QWERTY row (i can make it work by flexing the connector away from the motherboard) but no ctrl or shift keys.

I'm negotiating a new A1200 keyboard on amibay and hope that the keyboard connector on the motherboard isn't the problem.

Fingers crossed...
Nice tip,
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Old 24 October 2008, 03:47   #9
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Hello,

here is a post I have done on A.org after some searches on the Web for the ZIF connector.
Quote:
I am trying to find a ZIF connector where I can plug an A600 or A1200 keyboard.
I know the A600's is 30-pin and the A1200's is 31-pin.
The pitch seems to be 1.25mm (I have a Micronik Key6620 board and if I put a standard 0.1" IDC connector next to the ZIF connector, I can see that it does not align perfectly, so it should be 1.25mm and not 1.27mm).
Amphenol has the G27 serie that looks very close to what is in the Amiga (http://www.amphenol.co.za/CatPages/FFC.pdf).
Unfortunately, it is 30-pin max, just good for the A600.

Any idea ?

EDIT : I just found the one used by Micronik adapter:
http://www.allproducts.com/ee/joint-...connector.html
or on Amiga :
http://www.allproducts.com/ee/joint-...connector.html

The 31-pin connector is impossible to find.
Here are the Molex part number :
0039532314 : 31-pin, right-angle ZIF
0039532315 : 31-pin, straight ZIF
0520443145 : 31-pin, right-angle, non-ZIF
0520453145 : 31-pin, straight, non-ZIF
But, the distributors have 30 or 32-pin connectors.
Regards,

Frederic
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Old 28 October 2008, 14:56   #10
FrenchShark
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A1200 keyboard schematics

Hello,

I have just finished reverse-engineering the A1200 keyboard.
The SW number in the schematics is the keycode defined in the HRM.

Hope this will help.

Regards,

Frederic
Attached Files
File Type: pdf A1200_Keyboard.pdf (53.5 KB, 729 views)
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Old 05 September 2009, 02:15   #11
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Hey! I just fixed my A600 keyboard cable by getting some conductive silver laquer for 5€.

I slathered it all over the end of the flatcable, let it dry and then scraped off the laquer in between the fingers. (I tested with a multimeter that none of the fingers were connected.)

I had to let the silver in the 3 gram bottle settle to the bottom first, and used a tooth pick to apply it, making sure I didn't have too big a blob of the stuff on the tooth pick by scraping off the rim of the bottle. (Thx Jope for the toothpick tip!)

I had the cable working before, but right shift, and Alt-Amiga combos didn't work. I got the stuff from here http://www.kjell.com/?item=89313&path=

Photo here


[Edit: I probably could have fixed it if I'd cut off the flatcable and somehow removed the plastic from the end of it - however I couldn't find out how to do that without cutting off the cable :P]
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Old 23 September 2009, 20:56   #12
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Well, I thought I fixed it. It worked perfectly for a couple insertions, then some keys started failing again. The strips on my keyboard cable had been very worn down by the connector (I shone a flashlight from the back and saw almost all stripes let light through them).

And applying conductive silver made everything work, except - some Alt and Amiga keys failed again after a while, when the ZIF socket blades had easily scraped the conductive silver from the "holes" in the strips.

My solution:
I cut off 1cm from the cable, took some duct tape (any strong-fastening tape will do), and ripped off the tape in the direction of the strips (ripping perpendicular didn't remove any green stuff). I made a very light cut across the cable where the green stuff should start getting ripped off, beforehand. Make sure you don't cut off the stripes! Anyway, after I ripped off the tape the green stuff didn't come off exactly at the cut anyway, so mainly the cut is just for making the last 1 cm of green stuff be detached from the rest of the green stuff above 1cm. (Crap wording, hope you know what I mean.)

When the strips were exposed, I carefully painted the strips with a tiny brush with conductive silver to protect them, and made sure there were no shorted stripes by measuring with a multimeter and carefully scraping off conductive silver between the shorted strips. Use a light hand, it's easy to go non-straight and scrape off the silver on a stripe! The silver sticks permanently to the strips, but comes off easily with a thin radio screwdriver, or in my case, carefully scraping with the back of the tip of a scalpel ("Xacto" knife to Americans?)

The conductive silver laquer was a bit thin, but the "settled" stuff on the rim of the bottle was a bit thicker and was easier to apply with the brush.

The brush was a super tiny artist's brush from a store that sells pens and papers and stuff. It wasn't easy to apply even if the brush was perfect, but it was much easier than with the toothpick, because the brush would hold the laquer better so I could paint 5 strips per "dip", and it was easy to scrape it off a little to have a proper amount in the brush, and not a "blob".

I double-folded some duct tape and put it in a clamp to hold the cable steady - but if the keyboard is loose, you could tape it to a table, that should be easier.

I put the silver about 3 mm to 10 mm from the end of the stripes, since that's where the ZIF socket blades clamp.

I tried a thin piece of Scotch tape on the back of the cable before I made the above solution. But I don't recommend it, it only wears out the stripes sooner. If it doesn't work without it, it's more likely that you have some more work to do on the cable than that the ZIF socket doesn't clamp hard enough.

After applying the silver stuff, I tested each stripe with a multimeter so that the silver really did have 0 resistance to the unpainted part above the silver on the same strip. The silver stuff reacts strongly with the case of the plastic, so have some paper at hand if you should spill a drop. It also smells like nail varnish and should be very hazardous to your health, so do it on the balcony or open a window when you're done. Dangerous stuff, wash your hands after.

Sorry for the silly level of detail of this description but it really isn't as easy as "apply silver with a toothpick".

Last edited by Photon; 23 September 2009 at 21:32.
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Old 09 April 2013, 12:02   #13
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Originally Posted by AmigaJules View Post
One last update on this.

I discovered (accidentally) that putting some regular scotch tape on the green stuff, letting it sit for an hour, then removing it takes the green stuff right off. So I have nice clean traces on the ribbon now. Cut a fresh square end on it and plugged it in. Still have intermittent QWERTY row (i can make it work by flexing the connector away from the motherboard) but no ctrl or shift keys.

I'm negotiating a new A1200 keyboard on amibay and hope that the keyboard connector on the motherboard isn't the problem.

Fingers crossed...
AmigaJules i have the exact same problem as you that whole qwerty row + enter,tab and left arrow is non functional. I have one question if new keyboard from aminet resolved your problem with this or if not, what was the problem?

thanx
 
Old 09 April 2013, 12:54   #14
Fingerlickin_B
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Using a pin or small pick, one at a time, carefully bend the contacts inside the mobo's keyboard connector outward (into the slot).

PZ.
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