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-   -   [Absolute last resort] Solution to A600 (maybe 1200?) keyboard cable problem (http://eab.abime.net/showthread.php?t=51596)

Akira 15 March 2010 21:01

[Absolute last resort] Solution to A600 (maybe 1200?) keyboard cable problem
 
1 Attachment(s)
DISCLAIMER: I am NOT responsible for any damage you may cause using this method. If you turn your keyboard into a useless pile of poop, it's on you.

[Last updated December 30th 2015]

First of all, if this has been posted before, sorry, I didn't find it with the search function. Since it's a very common problem I thought it was worth making a thread about it.

Anyway, my A600 is alive and kicking again!
After taking it to an electronic repair shop (that took a sweet month and a half to replace all but two caps because he was lazy) it's back into action like always!

When plugged in, however, I realized the keyboard doesn't work at all. The bloody ribbon, which was playing hard to use, just stopped working completely. How fucking annoying. I have an extra membrane but for the A1200.

So, my brute force solution: I cut about 7mm (or more) worth of the tip, then gently scratched the conducting traces with a scalpel (or scissors or whatever you want) to expose the metal. To my surprise, it worked perfectly.

Here's a pic of how it looks like:
http://eab.abime.net/attachment.php?...1&d=1451494277

Of course, you can do this more elegantly, I bet :P
As suggested by Jope, I would start b cutting just 1mm and then try to cut more if the method fails. Try not to cut off completely the original contacts!!

I am very happy to have the A600 running again. It's been with me for 17 years already :D

This method will work for an A1200 membrane too.
It has NOT been tested, though, in a BLUE MEMBRANE A600. I am not sure it would work the same way. Anybody tried it?

Idea for betterment: add conductive paint to the newly exposed traces, for better contacts. (Suggested by alenppc below)

I hope it helps someone with their keyboard problems.


BIG ADVICE FROM OUR FRIEND JOPE
Quote:

Originally Posted by Jope
Please only use this approach as a last effort fix on a keyboard you are prepared to write off anyway.

If you are not careful, you can end up scraping too much and you end up with the same problem you were trying to fix in the first place.

As the first thing to try, you can cut off 1mm at the end of the flexi connector to make the contacts on the motherboard connector touch higher up in the black stripes.

And always ALWAYS unlatch the motherboard connector's sleeve before you plug in or remove the flexi cable. The sleeve slides up around the connector a few millimeters. Pull it up and only after that should you remove the flexi cable.


Bloodwych 15 March 2010 21:13

It's great to see your name popping up from time to time on EAB buddy!

So pleased you've got your A600 working again. You know what I'm going to mention now don't you? Your A600 Workbench you never got around to completeing!

So, now it's back in action - do you have a hard drive for it? Or are you thinking of upgrading it with a CF card?

Looks in great condition. Two months for cap replacement is pretty bad. Perhaps time to get a soldering iron and have a go yourself.

Akira 16 March 2010 04:33

Hi man!
After using this A600 all day today I can say I am amazed I ever worked in such a slow environment :P I guess I Am spoiled by my 030 A1200! So I don't know how much of a reason would exist behind making an A600 workbench install.

Anyway, it looks better in pics than IRL, it's quite yellowed. But it's been my Amiga since 1993 and I deeply apreciate that.

The machine has a hard drive that still spins to life (incredible!), and I got a CF adapter for it but all it does is lock up the machine. I wonder if it is the adapter or the card... I did try with another card, same results (a hum on the screen)

Also, and this is weird, when the machine has no hard drive activity, I can see a hum onscreen, like a refresh bar or something. When it reads the HD, it goes away. Maybe oneof the caps is not of the exact same type?

Akira 03 December 2010 15:43

Seems like the original pic got missing. I will fix this soon.

corpsicle 24 April 2012 08:28

Sorry for reanimating such an old thread.
But i got an a1200 with this keyboard problem.
And since i already ordered a new keyboard im gonna take the risk and try this fix on the old one.
Will report later how it worked. =)

Akira 24 April 2012 11:47

Cool. It's always worked for me! But I should add to this post a disclaimer: if you break your Amiga while performing this, for example by scratching too much, i ain't responsible :P

roy bates 24 April 2012 15:34

ive done this myself on a few amigas,it works well!

it also works on spectrum keybaords.

Akira 24 April 2012 17:09

Nice to hear! I guess it would work on any flat ribbon type contact that goes bad/eroded/rusty.

BarryB 24 April 2012 22:19

I had this happen on my A1200, posted another fix in another thread but can't remember where. Anyway, what I did was to cut about 10mm of the end of the flat cable then with the edge of scalpel you can gently lift up the green film from the corner and peel it back to expose the contacts, then you can slice off the green film once you've peeled back enough. Just make sure the exposed contacts are long enough to slide back into the keyboard connector on the board.

corpsicle 26 April 2012 08:53

Ok.

I cut off approx 7mm off the end.
Peeled the green film and scratched a little bit for good measure.
Plugged it in, and i had the _exact_ same buttons not work. o_O
How is that even possible ?

I was just about to give up, but figured what the hell and just sprayed some IPA in there and rubbed a bit with a toothbrush.
Plugged the keyboard back in, and this time everything works fine. =D
So i cant really confirm if it was this fix that worked, or if it was the 10th cleanup or so that finally did it.

Either way it works now and i have a brand new replacement keyboard coming in the mail too. ^_^

mancity 03 May 2012 09:13

I have tried this on my 1200 keyboard and having a couple of problems...

The end of the ribbon cable is like a stuck-on green section of about 5cm in length. I peeled this off and cut about 10mm of the ribbon cable with the aim of then exposing the wiring within it at the end, and then re-connecting the green plastic section to give it thickness when it back into the keyboard clip.

However, I cannot expose the wiring on the ribbon cable at all? I am going to try scraping it with a stanley knife tonight but I highly doubt there will be any success.

BarryB 04 May 2012 23:36

@corpsicle: You may have had some debris lodged in the keyboard connector on the board, repeated insertions might have dislodged it or compacted it so it wasn't causing a problem anymore, just a guess!!

alenppc 04 May 2012 23:45

Someone correct me if I am wrong, but only the very bottom of the cable is conductive, which is why you should never cut off more than 1-2 mm at most. I don't think you can expose the contacts within the flat cable itself, although the damaged ones can be reinforced with conductive paint.

If there is a way to expose the contacts from within the flat ribbon cable, then I may have a chance of recovering my blue membrane A600 keyboard as well.

prowler 05 May 2012 00:03

Quote:

Originally Posted by mancity (Post 816072)
However, I cannot expose the wiring on the ribbon cable at all? I am going to try scraping it with a stanley knife tonight but I highly doubt there will be any success.

If you start this task with that attitude, you are almost guaranteed to fail!

Think positive, take your time and be very, very gentle and you should succeed.

Make sure the blade is either new or hardly used, so that the edge is undamaged.

Work on the cable with it resting on a flat, hard surface and secure it with a piece of wood and G-cramps if possible, or get someone else to press down firmly on the wood to hold it steady.

IMHO, you would be better off using just the blade without the handle and starting with the blade resting on the cable so that it is parallel to it with the edge at the point from which you wish to start stripping the insulation, then gently lift it so that the chamfer of the blade rests parallel with the cable and then lift it a bit more and then carefully pare away a very thin layer as wide as the blade right to the edge. You will have to repeat this a number of times until the insulation is stripped right down to the conductors across the full width of the cable.

Good luck! :)

ramparts 05 May 2012 00:18

i would not recomended to cut the cable but pencil graphite would do very good contact
i think should cut as if you cut any of the traces would eventually brake later,well that is my opinion

regards Gonçalves portuguese amiga comunity

FOL 05 May 2012 12:02

Quote:

Originally Posted by ramparts (Post 816511)
i would not recomended to cut the cable but pencil graphite would do very good contact
i think should cut as if you cut any of the traces would eventually brake later,well that is my opinion

regards Gonçalves portuguese amiga comunity

The problem is, its hard to get pencils that have conductive elements.

Retrofan 05 May 2012 12:18

You can try with Graphit 33, but it hasn't given me very good results.

spanner 08 July 2012 00:35

Make sure you just take off the plaste coating only so don't scrape to hard on the ribbon. or you will have to get a new keyboard.I will have too do this with mine,I did it once before and messed it up and had to get a new keyboard

spanner 08 July 2012 16:46

Is there any differents beteen the A600 ribbon and the A1200 ribbon,..?

Commodore should of kept the way the A500 keyboard is,its not a ribbon..

roy bates 09 July 2012 00:21

Quote:

Originally Posted by spanner (Post 827861)
Is there any differents beteen the A600 ribbon and the A1200 ribbon,..?

nope.


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