6128 keyboard woes *** SOLVED ***

[00WReX]

Just thinking about it...did you only rub the 1st centimtre or so...roughly only the area above (on top of) the white backing section ??
Maybe all is not lost...maybe, possibly, you could cut the ribbon just above the white backing section and start again...

Can you post up a picture ??

Not sure if it will work, but it's sounding like you have not got much to lose at the minute...

Shane.

[ervin]

Just thinking about it...did you only rub the 1st centimtre or so...roughly only the area above (on top of) the white backing section ??
Maybe all is not lost...maybe, possibly, you could cut the ribbon just above the white backing section and start again...

Can you post up a picture ??

Not sure if it will work, but it's sounding like you have not got much to lose at the minute...

Shane.

That's exactly the next thing I'm going to try.

Do you have any recommendations regarding the type of glue to use, to stick the thick plastic to the end of the ribbon?
(i.e. remove the rigid plastic strip from the current end of the ribbon, and stick it to the "new" end of the ribbon).

I'm way too embarrassed to post a picture of the way it looks at the moment.
It's all a bit of a dog's breakfast.

[00WReX]

Not sure about the best glue to re attach the rigid white section...let me think about it (getting late, I need sleep).

BUT...do not worry about that part just yet. Really that white backing section is just to add thicknes to the ribbon to press it against the contacts in the connector & also to add rigidity to the ribbon when inserting into the connector.

You could probably, I'm pretty sure just hold it firmly against the the rear of the ribbon when you insert it...that would probably be good enough for starters to just see if the ribbon fix has worked...

Shane

[Bryce]

Good plan. You can re-glue the white plastic bit with any general glue, but I would probably choose some type of super-glue. Move the white bit first, then cut the ribbon. Also, the tracks are standard 2,54 pitch, 1.8mm width. I would suggest making some sort of mask/template to temporarily tape onto the ribbon to make the silver paint job a little bit easier and neater.

Bryce.

[ervin]

Thanks guys.

I *should* be asleep now, but I can't let it go.
I've cut off the end, and found that the rigid plastic bit is still quite self-adhesive.
So I've stuck it onto the new end of the ribbon.

I've also applied conductive ink to the tracks (using a toothpick) as neatly as I can.

Once it has dried and cured, I'll give it a test.
Probably at this time tomorrow night!

Alrighty, I'm off to get some shut-eye.

[Gryzor]

Man, this thread makes me sad, really.


Let us know how it went when you wake up!

[ervin]

Hi Gryzor.

I tried the "fixed" connector this morning before breakfast, and it didn't work. I'm not sure why.


Anyway, today I went to an electronics store and got myself a multimeter, with a view to trying some other things tonight.

Luckily, before I began, I logged on to this wonderful forum (it's always my first stop on the net), and I found a very generous offer from ynot.zero regarding a 6128 keyboard membrane.


I think I'll see how that goes before I do any more surgery on my broken membrane.

I am once again full of hope!
Fingers crossed!

[Gryzor]

Yay for the community then. Even if you don't find out what's wrong with the one you have...


However, it's a shame because you'll have to wait to use the HxC

[ervin]

Yay for the community then. Even if you don't find out what's wrong with the one you have...


However, it's a shame because you'll have to wait to use the HxC

That is indeed true... but if the replacement keyboard is successful, at least I will be able to use the HxC!

[ervin]

Okay, using the multimeter, I've identified where the problem is.
And it appears to be the place where the original problem was, before I stuffed it all up!

It's the spot where all 8 lines come together, where the 2 foils are stuck together over the spot where all 8 lines "merge".
Taking the membrane foils apart has made the problem much worse, as now none of the 8 lines have conductivity over that point where the 8 lines merge. It appears that when I pulled the foils apart, it damaged the lines. Sigh...

I did a heck of a lot of testing with my cheap and cheerful multimeter, and it didn't matter where I tested on the originally non-working line - there was conductivity. Once I put on of the probes on or past the merging of lines, I lost conductivity.

I *may* be able to fix it, but it will take a lot of time and patience, and a steady hand.
Most likely my attempt will fail.

Nonetheless, if the replacement is ok, I won't be trying to fix this one anymore.

I guess the upshot of all this is that the membrane is pretty much fine, apart from the merging bit.
All the key pressure pads appear to work.

[ervin]

WARNING: long (but hopefully fascinating) post ahead!
(BONUS: Ridiculous photos included at the end!)

Alrighty, the replacement membrane from ynot.zero is on the way.
I am so grateful - I can't even begin to express how thankful I am. 

While I wait for it to arrive, the dead membrane of course continues to haunt me.
Last night I stayed awake way too late trying various things with aluminium foil tape and a multimeter.

The first few ideas I had showed brief sparks of promise, but really didn't get anywhere.
I discovered that aluminium foil tape doesn't conduct particularly well, when you stick smaller lengths of it together in order to make longer traces.

So I thought, why not stick two fat bits of the foil tape together (adhesive side to adhesive side), and then trim it to a narrow strip?
I did so, and of course it was conductive across the length of the strip.

I then started by sticking one end to the bit that goes into the motherboard keyboard connector (being careful to leave aluminium exposed on the bit which actually plugs in to the connector). Then I used narrow strips of non-conductive adhesive tape to stick the foil to the membrane, along one of the black lines.

Where the black line bent around corners, I folded the aluminium foil strip over itself to change direction.
I worked my way around to the first circular sensor thing, carefully covering the foil strip with tape as I went along.

When one line was done, I tried plugging the membrane back into the cpc.
And holy cow... it worked. The numbers along the top of the keyboard, that are connected to that membrane line, all worked! I could not believe it!

I then did the same for the second line. Because I had covered the first line in tape, the second repair line remained isolated from the first repair line, and after some patient folding, sticking, and multimeter testing, I had a working second line!

As it stands now, all the keys along the top (connected to the first two trace lines) work!
EXTREMELY HACKY, but it works! 
(Could this be one of the hackiest keyboard fixes/mods ever?)

I'm not sure it's worth trying to fix the entire membrane, as it will become a rather messy amalgamation of aluminium foil and adhesive tape, but I'm just excited that I've been able to make some of it work using my crude and clueless techniques!





Regardless, none of this will matter if the replacement membrane is in good condition. But I had to try, didn't I?

[00WReX]

Hahaha, good to see you persist with it...sounds like you are learning a bit along the way, especially now that you have a multimeter.

Just wondering why you went so far with the aluminium foil...If those lines were working prior to you sanding the connnector away, would have thought you would only need to go only a few centimetres along the ribbon, and not even get near the actual membrane ??

It may be required for you original faulty line though, have you had any luck testing the continuity with your multimeter and in indentifying the break (on the original faulty line) ?

Is one of the lines you have attempted to re-create the original faulty one (without pulling one of mine apart, i can't remember what line looks after what key range) ?


Cheers,
Shane

[ervin]

Hahaha, good to see you persist with it...sounds like you are learning a bit along the way, especially now that you have a multimeter.

Just wondering why you went so far with the aluminium foil...If those lines were working prior to you sanding the connnector away, would have thought you would only need to go only a few centimetres along the ribbon, and not even get near the actual membrane ??

It may be required for you original faulty line though, have you had any luck testing the continuity with your multimeter and in indentifying the break (on the original faulty line) ?

Is one of the lines you have attempted to re-create the original faulty one (without pulling one of mine apart, i can't remember what line looks after what key range) ?

Cheers,
Shane

Yep, I certainly am learning quite a lot. Being a stubborn bugger certainly helps!
Though I won't be building my own circuit board just yet! 

The foil tape had to go onto the membrane because when I pulled the membrane apart, the glue that was holding the 2 halves together must have taken some of the black line with it, right where the ribbon expands out into the rest of the membrane. I probably went a bit further than I needed to, possibly out of paranoia, or perhaps enthusiasm. 

The original faulty line hasn't been fixed yet.
(It's the one at the top of the photos).
I thought I'd test some lines that used to work before I broke it all.

From what I understand, it appears that the original problem was caused by pretty much the same problem (though it wasn't caused by me!). According to my multimeter tests, the entirety of the original line is fine along the membrane, but at the point where it all converges to the ribbon, conductivity is broken.

[00WReX]

Ahh, I see...thought there must be a reason for those lengths of foil.

Yeh, I know what you mean about being stubborn...got a bit of that myself, get something in my head and I can be like a dog with a bone.

All good though because you tend to learn a bit.

Cheers,
Shane

[00WReX]

Just re-read a couple of earlier post's...yes you did already mention the pulling apart of the membrane damaging the lines...
I forgot all about that bit    And I had read it previously 


I blame it on old age    , along with too much work & not enough sleep 


Cheers,
Shane

[ervin]

Just re-read a couple of earlier post's...yes you did already mention the pulling apart of the membrane damaging the lines...
I forgot all about that bit    And I had read it previously   

I blame it on old age    , along with too much work & not enough sleep   

Cheers,
Shane

No problem, a lot of stuff has been discussed in this thread, so it's easy to forget what has happened thus far.
I'm with you there on old age, too much work and not enough sleep!

Speaking of old age, it's amazing to think that I defeated Jet Set Willy 26 years ago, and Head Over Heels 25 years ago. And I still remember those moments!

Uh oh, time to go wildly off topic!

I remember seeing Alien 8 for the first time, in what was then my local computer store.
I even remember the colour scheme of the screen that I first saw (red and yellow, with orange from stippling), which way I was facing and where the cpc was in relation to the door of the shop!

Same thing with Elite. I can remember the moment like it was yesterday.

Funny the sorts of things that stay in memory eh?

I often wonder if my unhealthy desire to have a working 6128 is a result of trying to hang on to those moments so tightly, tooth and nail.

[00WReX]

Totally agree with you mate.
I think the "hanging onto fond memories" aspect is probably the case for a fair few people, not only on this forum...but people who still use & collect retro things in general.

Did you have an Amstrad back in the day or did you use a mates ?

I have a few interesting stories (well interesting for me) around a few of my CPC's and how I obtained them, but might bore others to death.
Just quickly...
I still have my original 464 from 1985...and it is in mint condition...I also have the very first 464 I laid eyes on and used...my good mates one.
I also have a couple of ex South Australian High School 6128's (what was Strathalbyn High School), another long story with those.
Both my mates & the high school computers I obtained in 2003 after chasing up some real long shot's and not very likely leads...

Just recently my nostalgia got the better of me & I purchased a small collection of another brand 8-bit computer, purely because I had fond memories of using them as my local High School computer for the duration of my time there.

Anyway, I've already gone on too much...old age again, now I'm telling stories...

Cheers,
Shane

[ervin]

That's brilliant - I love reading stories like that.
"When I was a boy..." 

I did indeed have a cpc back then - a 464 with green screen monitor!
On special occasions the MP1 was used to add a bit of colour to proceedings.
I remember the first time I saw Sorcery running in colour - my jaw just dropped.
Gryzor was of course just mindblowing as well.

I went to (long since closed) West Lakes High School back in those days, and they had a room full of 6128's.
I knew how to use them better than the teacher; not many people had home computers back then.
We used Tasword a lot to learn how to "use computers".

And we played some crappy cricket game with stickmen when the teacher wasn't nearby. 
[EDIT] I think it was this one: http://www.cpc-power.com/index.php?page=detail&num=2207

It'd be amazing if I could find out whatever happened to those 6128's, but I wouldn't even know where to start.
I suspect that some of the teachers may not even be with us any more... time marches on.

I had a few friends with CPC's, and some with C64's, so I got to play on both sides of the fence.
Great days indeed.

[00WReX]

A few of our stories can be found here...

Your Earliest Memory of the CPC?

and here

NEW ATARI 600XL COMPUTER IN CLOSED NEVER OPEN BOX





Cheers,
Shane

[ervin]

Fantastic stuff!
Might be time to re-read that earliest memories thread.

Your post in the atari 600xl thread about how you got those 2 6128's is astonishing.
You lucky bugger! 

That lot must be worth quite a bit, though I can't imagine you'd ever want to sell any of it!

[robcfg]

I knew how to use them better than the teacher; not many people had home computers back then.We used Tasword a lot to learn how to "use computers".

I know that feeling. When I was in school we also had CPC6128's and I used to do my assignments in 510 minutes and then played Camelot Warriors with my teacher 


Also, a great moment I remember is when I brought Samantha Fox Strip Poker... boy, what a show! 

[Bryce]

Sorry for breaking up you trip down memory lane and wandering back to original subject:

Cool fix erwin, but I doubt it would last very long and to put it in Australian speak, it's probably as reliable as a 80's Holden, but well worth the bother just for the learning aspect.

Bryce.

[00WReX]

Sorry for breaking up you trip down memory lane and wandering back to original subject:

Spoil sport 

Cool fix erwin, but I doubt it would last very long and to put it in Australian speak, it's probably as reliable as a 80's Holden, but well worth the bother just for the learning aspect.

Bryce.

That's totally unfair Bryce...an 80's Holden would never have been that reliable 

Anyway, where did you learn about the Aussie Holden ? (woops, off topic again) 

Cheers,
Shane

[Badstarr]

I guess that multimeter is earning its keep! Congratulations on at least restoring some functionality, any victory in these matters represents a good learning experience. The keyboard I'm using on my GX4000 plus modification is getting a little problematic I think it may be a faulty membrane as all the connections seem ok so I may have to use the keyboard from the faulty 6128 I just bought. Well at least as a temporary solution. I suppose the keyboard membrane gets the most mechanical punishment so some problems are to be expected. I might have a try making a membrane from scratch when I have the time, just for the hell of it   

[ervin]

Sorry for breaking up you trip down memory lane and wandering back to original subject:

Cool fix erwin, but I doubt it would last very long and to put it in Australian speak, it's probably as reliable as a 80's Holden, but well worth the bother just for the learning aspect.

Bryce.

Yeah you're probably right, it likely isn't the most reliable solution.
Incidentally, I've always driven Holdens, and they've been great!

I've now got 4 lines wired up, including the one that caused all this hassle in the first place.
Out of those 4 lines, it's that original one that now still isn't working with my hacky fix!


I get a reading on the multimeter from the space bar's sensor to the ribbon, so the keys are actually registering.
It seems that the keyboard connector might be the culprit.
Grrr... all this hassle because of that!

[EDIT]
Then again I'm not so sure.
When I use multimeter probes from the top of the connector (on that line) to the soldered bit under the connector (where the connector plugs into the motherboard), I get a reading. So at least current is indeed flowing through the connector on that line.

But I don't know where else to look. 
I can't tell on the back of the motherboard where those lines lead. They're really thin and many lines don't actually seem to connect to anything...