CDTV to 1200 Keyboard Hell

[gklinger]

I got it in my head that I want a black Amiga 1200 so I went out and bought a CDTV keyboard and after looking at it for more than a year I decided it was time to take a crack at swapping the keycaps over to a 1200 keyboard. I naively thought this would be a snap. The big problem I've encountered is that my CDTV keyboard has the larger reverse-L return key and my 1200, like all 1200s as far as I know, has the smaller return key and there doesn't appear to be an easy way to get them to fit. I even took the keyboards completely apart to see how if I could graft the CDTV one into the 1200's keyboard frame but that's a no-go for a variety of reasons the least of which is that they're based on completely different designs.

I searched around for pictures of black 1200s to see what others had done but it appears they all used international CDTV keyboards with the smaller return keys. It may be that's it 2am here or that I've had a few pops but I can't see an obvious way to make this work and I'm at the end of my rope.

Any ideas or suggestions?

[rkauer]

Just one idea for you:

Use the whole keyboard inside your 1200. Open the CDTV keyboard, strip the wires out (it is a simple connector), route 4 wires from the keyboard to the A1200 MPU.

That's the very same hack used when you want to replace the busted A1200's k/b with an A500's one.

[gklinger]

J Use the whole keyboard inside your 1200.
Could you elaborate please. The metal whatsit that the keyboard sits in is a different shape and I'm not sure how to get it to fit in a 1200.

While I'm at it, I remember reading something about the 1200 keyboard being crap (something about it not reading multiple keys). If I use the CDTV keyboard will I avoid that issue? Also, I have a spare 500 keyboard so if I can use that to make this go, I'm all for it.

I can't tell you how happy I am that you're taking a crack at helping me with this. If Zetr0 shows up I might not actually have a nervous breakdown.

P.S. I'm a little drunk so please excuse me if I'm being :nuts

[rkauer]

No problem.

But I bet Z is zzzzzzz by now.

Please check again the CDTV keyb. It's different???? Strange...:confused

The keys fits on the A500 one? If so, you can swap the keys with the A500 one and then do the keyboard hack.

For the multiple presses "bug": no, the A500/CDTV suffer from the same "disease".:(

Any typo here can be credited to a bottle of white wine (15°GL). Yay!:)

[alexh]

Some CDTV keyboards are A1200 compatible. I think that USA ones have the different return key.

http://www.amiga.org/modules/myalbum/photos/4051.jpg
http://www.amiga.org/modules/myalbum/photos/2067.jpg

[gklinger]

Exactly. My CDTV keyboard with the larger, inverse L return key has the same chassis as the one depcited above but the actual keyboard looks exactly like the one TjLaZer used in his black 500 project (http://eab.abime.net/showthread.php?t=36016). Like this:

http://www.vintagecomputercafe.com/pics/amiga/black500/black5001.jpg

Part of my desire to use this keyboard is that I really hate having those blank keys on my 1200. There has to be a way for me to use this keyboard in a 1200 even it requires some creativity.

[RedskullDC]

Hi Alexh,

That second pic is my 1200 desktop machine ;)
That pic from Amiga.org?

Cheers,
Red

Some CDTV keyboards are A1200 compatible. I think that USA ones have the different return key.


http://www.amiga.org/modules/myalbum/photos/2067.jpg

[RedskullDC]

Hi gklinger,
Exactly. My CDTV keyboard with the larger, inverse L return key has the same chassis as the one depcited above but the actual keyboard looks exactly like the one TjLaZer used in his black 500 project (http://eab.abime.net/showthread.php?t=36016). Like this:

pic deleted.

Part of my desire to use this keyboard is that I really hate having those blank keys on my 1200. There has to be a way for me to use this keyboard in a 1200 even it requires some creativity.

The large return key should replace the smaller return key, plus the adjoining <blank> key.
Can you show us a pic of the underside of your large return key?
Should just mate with the keyswitch when you remove the <blank> keytop.

Red

[alexh]

The large return key should replace the smaller return key, plus the adjoining <blank> key. Should just mate with the keyswitch when you remove the <blank> keytop.
Interesting. Certainly looks at first glance that might be the case. Would you need to remove the <blank> key pressure pad and spring?

http://i14.ebayimg.com/01/i/000/fe/31/2312_1.JPG

P.S. Yup. I needed an image so I googled for one.

[RedskullDC]

Hi Alexh,

Interesting. Certainly looks at first glance that might be the case. Would you need to remove the <blank> key pressure pad and spring?

http://i14.ebayimg.com/01/i/000/fe/31/2312_1.JPG

P.S. Yup. I needed an image so I googled for one.

Probably best to leave the post/spring in place, otherwise the return key will tend to twist on the other remaining keyswitch stalk.

Red

[alexh]

I wasnt sure if the return key was supposed to have more than one and if it would fit.

[RedskullDC]

I wasnt sure if the return key was supposed to have more than one and if it would fit.

Occured to me after posting:

May have to electrically isolate the pins from the Blank keyswitch.
I can't remember of the top of my head whether it generates a scan-code or not...

Red

[gklinger]

Can you show us a pic of the underside of your large return key?
Sure. See attached.

Should just mate with the keyswitch when you remove the <blank> keytop.
My first thought was to put reverse L return key where the smaller return key and the blank key are. I was just going to leave the rubber plunger off the blank key so that it wouldn't get pressed when the return key was depressed. I don't think that's going to work because the large key uses two metal brackets and the smaller uses one. :(

I took a look at my spare 500 keyboards and found that the one with two A keys is the same as the CDTV keyboard. The one with a C= and a A has a much nicer feel but it uses a third arrangement under the return key. I would just as soon use that keyboard in the 1200 but it doesn't look like it would by any easier to mate.

[gklinger]

I think I've had a breakthrough. I can use the 1200's keyboard mechanism if I replace the board that it uses with the 1200's membrane. I'll need to cut away some plastic from the 1200's frame (does that make sense?). The plastic frame of the CDTV keyboard is slightly larger on both sides but it looks easy enough to trim down. There's also a post that would need to go and I'd have to cut a slot for the ribbon cable to come out. If I did that I think the two keyboards could be made into one...

I may have to take more pictures for this to make sense.

[rkauer]

The scan code is generated only if the Amiga is using another language (localize). I can swear it.

My A1200 use brazilian keymap.

[gklinger]

That's excellent to know. Thanks. I've had a go at cutting the plastic with the tools I have on hand and it's hard going. I need a finer saw. I wonder if it would be easier to melt away? This is definitely doable though. Once I cut away a few mm from each side of the CDTV keyboard it should fit in the metal tray and I'm good to go.

What do you guys use when cutting through your Amiga cases? The plastic is somewhat similar.

[tonyyeb]

Melting will make it look horrible. Very hard to get it to look good. Fine blade, then file, then fine sand paper, then wet and dry paper.

[gklinger]

The piece I'm cutting won't be visible so I'm looking for the quickest and easiest route. I may just have a go at it with a Dremel.

[tonyyeb]

The piece I'm cutting won't be visible so I'm looking for the quickest and easiest route. I may just have a go at it with a Dremel.

Ah! Well melting will be the quickest! But I would personally go with the Dremel.

[gklinger]

Success! (sort of)

I cut down the plastic (with an xacto knife of all things) and got the keyboard to fit so I excitedly connected it up and all keys work except for the left shift and the big return which are, as it happens, the two keys that cover the original blank keys. :banghead

I took it apart again and looked at the membrane and sure enough, the feet for the large inverted L return key and the left shift are the only two that don't match up with the traces on the membrane which explains why it doesn't work. I've come too far to give up now.

Suggestions?

[gklinger]

I decided to take apart a 500 keyboard to see what's going on and I read the threads about using a 500 keyboard on a 1200 and I think I've think I've found a solution.

The 500 keyboard I have also uses a membrane that connects to a keyboard controller board. I removed the controller and plugged a 1200 keyboard in and connected the controller to a 500 and it worked flawlessly. The ribbon part of the 500's membrane terminates in a different place and is much shorter but it appears that I can bridge the membrane to the 1200's keyboard input and the problem will be solved. What I need to do now is find a couple of those little white ribbon cable receptacles and wire them together and then cut a segment of ribbon from the now surplus 1200 keyboard and connect the hack up to the board. I'm confident this will work.

[illy5603]

My CDTV keyboard is the exact same as yours and the keycaps don't match. I have decided to just leave the CDTV whole and go with whitening my current keyboard.

[Jope]

Why don't you just unscrew the black keyboard tray (with keycaps attached) from both keyboards and swap them..?

Are the contacts for shift + return in a different place or what is the problem.

I know the black tray isn't 100% the same shape, but the differences are really minor and I have done it myself a long time ago.

[gklinger]

Why don't you just unscrew the black keyboard tray (with keycaps attached) from both keyboards and swap them..?
They didn't fit which was why I trimmed down the CDTV keyboard. Then I ran into another problem...

Are the contacts for shift + return in a different place or what is the problem.
Bingo. :(

Anyway, I solved the problem by going with rkauer's earlier advice. I swapped the keycaps over to a 500 keyboard and I'm going to solder that to the 1200's MPU. I'm hoping to have some time in the next week or two to finish this project up and then I'll post pictures.

[adonay]

I had this problem too i ended up using the amiga 1200 enter and shift "painted black

[UncleSpam]

To resurrect the subject...

After looking at the A1200 membrane, I've come to the conclusion that the best way to work this issue is to "relocate" the contact points on the membrane for the Return key and the LShift key.

I'll have to think of some material that I can use to reroute the existing contact points... that may prove to be an issue.

Bogdan

[UncleSpam]

Task complete.

Took the original A1200 keyboard membrane and rerouted the Return and Left-Shift contact points by overlaying the membrane on top of the CDTV keyboard circuit board and marked the locations of the contacts on the A1200 membrane.

Note: This is only required if you are using the American CDTV keyboard layout.

To reroute the contact points, I used copper trace repair tape such as this:

http://www.electronix.com/catalog/product_info.php/products_id/5771

This comes in a 6 ft. roll of copper tape, of which, I probably used 6 inches (including the test runs).

I had to trim the plastic top portion of the CDTV keyboard by no more than 1/4" on the left and right side to allow it to fit the metal backing plate of the A1200 keyboard.

I also trimmed one or two standoff tabs.

The trimming was performed using a Dremel cutter and grinder. I used the grinder to smooth off the rough spots.

To ensure the keys of the keyboard don't get damaged, you can remove them prior to the trimming. I was careful enough not to damage them.

Once the mods are done, assemble the top CDTV keyboard board with the A1200 flexible membrane and backing metal plate and replace all the screws.

Done...

This mod was made in such a way that I can easily restore the CDTV keyboard to its original self by simply re-assembling the right components.

No functionality was lost in the modification.

The CDTV keyboard now hosts the A1200 keyboard top layer with the white keys (for storage purposes only).

Hope this helps.

- Bogdan