Keyboard pictures

[PJM]

Originally Posted by Jope

I found a picture depicting the two membrained A500 keyboard on Amiga.org .. Photo taken by a user called orange.



If someone has a kbd like this they want to part with, pm me please. :-)

I don't think they were made in any other layout than UK/US.

This keyboard design must be pretty common as I have three of these , all revision 6s.

[Jope]

Originally Posted by PJM

This keyboard design must be pretty common as I have three of these , all revision 6s.

The one I had was a UK layout, so it might be that the majority of those went to the UK. :-)

[rkauer]

Have one of those Samsung-made models which came with a rev5 A500.

Samsung & Mitsumi made exact same units.

One unknown fact for most: the A500 single connector is exactly the same "pin" order as the A1200 & A4000. One can use the membrane to salvage one A1200 or A4000. The only problem is the membrane is a lot shorter and in the wrong place for the A1200.

[Jope]

All A4000 (and other big box) keyboards I've seen don't have a membrane, but a PCB.

Never seen a Samsung that is otherwise identical to the Mitsumi, could you elaborate?

[ElectroBlaster]

Originally Posted by Jope

Reset works, because it is a separate wire that sends that in the A500.

I have a couple of bare ones and J05/06 are not linked in these.

If the caps light stays on, it seems the keyboard can't reset itself properly. I'd probably just swap the 6570 and perhaps the 555 timer, but I've never had that problem myself so I have no prior experience.

Holy thread revival!

I would like to transplant an NME A500 keyboard into an A2000 keyboard case that currently has a Mitsumi keyboard (same type as the CDTV possibly?).

I stumbled upon something when googling, there seems to be an A2000 keyboard that has the NMB keyboard as standard.

The reason for the swap, the mitsumi is in bad shape! keys are missing, posts are cracked and the plastic baseplate has damage. I will need to create a link between the A500 connector lead to the A2000 keyboard lead. Do you know if the keyboard reset thing works on the 2000? I need to know if it is a straightforward job or will I be needing to faff about soldering stuff.

Tia

[Jope]

Originally Posted by ElectroBlaster

Holy thread revival!

I would like to transplant an NME A500 keyboard into an A2000 keyboard case that currently has a Mitsumi keyboard (same type as the CDTV possibly?).

I stumbled upon something when googling, there seems to be an A2000 keyboard that has the NMB keyboard as standard.

The reason for the swap, the mitsumi is in bad shape! keys are missing, posts are cracked and the plastic baseplate has damage. I will need to create a link between the A500 connector lead to the A2000 keyboard lead. Do you know if the keyboard reset thing works on the 2000? I need to know if it is a straightforward job or will I be needing to faff about soldering stuff.

Tia

The NMB does not fit properly in the Mitsumi case, it will wobble around a bit. Nothing drastic but iy reminds you of what you have done. :-)

Remove transistor Q1 and the LEDs to make an A2000 keyboard of an A500 NMB.

As for the pinout, just work from the A500 keyboard pinout backwards to the keyboard PCB, as far as I remember the PCB connections are not 1:1 the same as on the A500 motherboard, but I might remember wrong.

[ElectroBlaster]

Originally Posted by Jope

The NMB does not fit properly in the Mitsumi case, it will wobble around a bit. Nothing drastic but iy reminds you of what you have done. :-)

Remove transistor Q1 and the LEDs to make an A2000 keyboard of an A500 NMB.

As for the pinout, just work from the A500 keyboard pinout backwards to the keyboard PCB, as far as I remember the PCB connections are not 1:1 the same as on the A500 motherboard, but I might remember wrong.

I thought as much regarding keyboard movement! in all my acumulated tat and scrap parts I have these little plastic things that were in a dead a500. I could probably make them fit somehow and it would keep things still.

Thanks for the info about what I need to remove from the circuit

[luigi75]

Originally Posted by Jope

I found a picture depicting the two membrained A500 keyboard on Amiga.org .. Photo taken by a user called orange.



If someone has a kbd like this they want to part with, pm me please. :-)

I don't think they were made in any other layout than UK/US.

I know this is an old post. I have a keyboard with double membrane, exactly the same as in the picture above, and I need to tear it down to solder a wire, but I do not know how to open the two membrane connectors. Can somebody help me with it?

[Jope]

These don't have a latch. You can wiggle the cable out.

[solarmon]

I use a pencil or chipstick to press the ribbon cable against it to provide extra support and to make it easier when pulling it out and pushing it in.

[luigi75]

Originally Posted by Jope

These don't have a latch. You can wiggle the cable out.

Done! I feared I could tear them apart.
Thank you!

[Jope]

Originally Posted by ajk

Anyone happen to know what the A1000 switches are exactly, and where some replacements might be obtained (eg. certain PC keyboards)? I'm not convinced they are Cherry, or at least they must have changed the design at some point.

ajk already knows this, but the rest of you might not. These are Mitsumi standard mechanical with the Mitsumi keycap mount.

[ajk]

Indeed, and the part number turned out to be "E25-33-137". The switches are still occasionally available in various online shops.

[Port89]

Seem this is a thread that likes being necro'd!

I've been cleaning up an A500 Rev 6A today which has the Samsung keyboard in it.

Before opening it, I was aware that the Caps Lock + S as well as ESC + F1 are somehow tied together. Ie, pressing either press both. I could see this in a CLI but using AmiTestKit shows both codes coming through.

The membrane itself isn't damaged and I've held it apart at the CL key while press S to confirm that it's not somehow just contacting.

I'm thinking it's got to be a decoding issue but where? Can the 6570 just decide to get these specific keys wrong?

[Jope]

It could well be fried so that one of the kbd matrix pins is permanently high or low.

[Port89]

Originally Posted by Jope

It could well be fried so that one of the kbd matrix pins is permanently high or low.

Good call. I tested a bit more and sure enough there is a trace which is common to all the double key issues. All down the left side but when I looked at where the trace went it also went to the top-right for the numeric keypads "*" key. Sure enough....pressing that also triggers the numeric '9'.

Are there any pinout or data sheets on the 6570-036? Or schematics of this keyboards PCB? Google and ChatGPT so far saying nothing, although CGPT does say "look on AEB!"

EDIT: It wasn't too hard to see what went where and 'line 14' on the top membranes 16 way cable seemed to be the culprit. Pulled it out, dusted it lightly, sprayed in a bit of contact cleaner and it seems to be working when I hold the ribbon connector in place.

The problem is, I can't for the life of me get it to 'pop' back in and it's an impossible angle with the 6570 blocking access. I'm having visions of cracking Spectrum 48k keyboard connectors.

Is there a trick? The socket doesn't seem to be the ZIF type you can release.

[Jope]

I don't think there's a trick really.. Use a pair of tweezers and hold it very near the end, feed it in little by little with the tweezers. Don't grip too far from the edge or you might kink the membrane.

[Port89]

Fair enough. So far, every time I get it back in I have the problem again.

I know it's not the IC or other electronics as I can "type" by using a piece of cable and shorting the pins of the IC to correspond to the keys I want to press. The 'bad' combinations work fine when I'm doing it this way.

I am noticing that unexpected pins go high (and very high eg 6v) such as pin 4 when I'm pressing ESC when the cable is attached. There must be something wrong/shorting either in the membrane socket or perhaps on the membrane itself. I'm thinking it's got to be the socket given it works when I hold the cable in lightly. I'm tempted to take the socket off the PCB for a look although I'm trying to avoid that for now.