How to: Convert an A500/A500+ Mitsumi keyboard to an A4000 keyboard.

Turran · 07 April 2013, 22:43

I bought an A4000 a while back with keyboard and had some problems with it. Turned out it was a converted A500/A500+ Mitsumi keyboard and CTRL-A-A did not work on it.

After Jope told me what to do ( here: http://eab.abime.net/showthread.php?t=67524 ) it worked just fine.

I thought I'd buy another A500/A500+ keyboard of the same type and redo the procedure, documenting it as I go for your pleasure!

This is a great way to restore a A4000 keyboard if its broken but you have the shell for it.

What do you need?
1: Amiga 4000 keyboard shell (not a requirement, but it will look better in the end)
2: A normal PS/2 keyboard cable. I cut mine from an old Cherry keyboard since it had the same curled up cable as the original A4000 keyboard does.
3: An A500/A500+ Mitsumi PCB A-500 keyboard. I bought mine on ebay for a dime basically. I'm not sure if other models work.

Picture of the correct model.

Now that you got that, you'll want to desolder the cable, the two leds (power and disk) and the transistor Q1.
If you do not remove Q1, CTRL-A-A will not work on big box amigas.

Picture - Desoldered front side
Picture - Desoldered back side

You now take your PS/2 keyboard cable, strip the cables and measure with a multimeter (beep mode) pins 1,2,3,4 and 5 on the picture below (Top right corner). Write that down.

Picture - Connections and where they go.
Please note that you can either put the ground cable to either connection marked with "5". Also note that this picture was taken from the keyboard I used as reference and it is not my shoddy soldering job =)

If, when you removed the old cable, you left the strap that is holding the cable still on, pull the new cable through it before soldering the new one on. Saves you a strap if it fits.
Solder the cables into their respective connections as per the picture above. I chose to put ground (5) next to the others.
If you did not pull it through the old strap, put on a new one now to secure the cable in place. STRAP THE CABLE THE OTHER WAY FROM WHAT I DID and its much easier to get it out of the hole in the keyboard chassi which is to the right...

Picture - Soldering done

And now you're done.

Almost done
Stick it in its new home!

Edit: I can happy report that it fits in an A2000 keyboard chassi as well, although you do have to cut away some of the plastic of the chassi that is holding the keyboard in place for it to fully close. Also, a little bit of the metal at the bottom of the keyboard was trimmed away for it to slide as far down as needed.

Jope · 08 April 2013, 09:51

Good job, the strain relief with the cable tie is also worth noting, soldered connections break so easily unless you tie the cables down near the joint.

Turran · 08 April 2013, 12:05

Oh yeah. I'll add a note on that.

tesla · 08 April 2013, 15:09

I couldn't help but read your talk about the Mitsumi keyboard, because I am looking for parts for one, perhaps someone reading this can help.

I have a Commodore SX-64, and the keyboard is a Mitsumi. One key mechanism was damaged. as a description, the key itself has two prongs with a small activation spring coming out of it, the two prongs attached to the key snap into a carrier with a large spring. The carrier itself also has two prongs, it snaps into two rectangular holes in the keyboards printed circuit board.

I am looking for one carrier. Can anyone help?

Thanks!

TjLaZer · 08 April 2013, 17:14

Awesome work, thank you for documenting it for us!

spannernick · 07 June 2016, 15:39

I know this is a old post but just wondered,if this works on a A4000,will this work on a Amiga CD32,I always wanted a keyboard for mine..?

It looks simple to do,Thanks for sharing.

Jope · 07 June 2016, 16:54

Yes, it will work in a CD32.

spannernick · 08 June 2016, 00:36

So the connector is a PS/2 connector like on my PC..?

idrougge · 08 June 2016, 10:12

Yes.

Turran · 24 June 2016, 16:24

I bought a few PS/2 male to PS/2 male cables on Elfa. Cut them in half and I have cables for 2 keyboards =)

ElectroBlaster · 15 September 2017, 22:46

Do you have to use a ps2 cable? Can you not just re-use the original cable?

07 April 2013, 22:43	#1
Turran Moderator Join Date: May 2012 Location: Stockholm / Sweden Age: 49 Posts: 1,571	How to: Convert an A500/A500+ Mitsumi keyboard to an A4000 keyboard. I bought an A4000 a while back with keyboard and had some problems with it. Turned out it was a converted A500/A500+ Mitsumi keyboard and CTRL-A-A did not work on it. After Jope told me what to do ( here: http://eab.abime.net/showthread.php?t=67524 ) it worked just fine. I thought I'd buy another A500/A500+ keyboard of the same type and redo the procedure, documenting it as I go for your pleasure! This is a great way to restore a A4000 keyboard if its broken but you have the shell for it. What do you need? 1: Amiga 4000 keyboard shell (not a requirement, but it will look better in the end) 2: A normal PS/2 keyboard cable. I cut mine from an old Cherry keyboard since it had the same curled up cable as the original A4000 keyboard does. 3: An A500/A500+ Mitsumi PCB A-500 keyboard. I bought mine on ebay for a dime basically. I'm not sure if other models work. Picture of the correct model. Now that you got that, you'll want to desolder the cable, the two leds (power and disk) and the transistor Q1. If you do not remove Q1, CTRL-A-A will not work on big box amigas. Picture - Desoldered front side Picture - Desoldered back side You now take your PS/2 keyboard cable, strip the cables and measure with a multimeter (beep mode) pins 1,2,3,4 and 5 on the picture below (Top right corner). Write that down. Picture - Connections and where they go. Please note that you can either put the ground cable to either connection marked with "5". Also note that this picture was taken from the keyboard I used as reference and it is not my shoddy soldering job =) If, when you removed the old cable, you left the strap that is holding the cable still on, pull the new cable through it before soldering the new one on. Saves you a strap if it fits. Solder the cables into their respective connections as per the picture above. I chose to put ground (5) next to the others. If you did not pull it through the old strap, put on a new one now to secure the cable in place. STRAP THE CABLE THE OTHER WAY FROM WHAT I DID and its much easier to get it out of the hole in the keyboard chassi which is to the right... Picture - Soldering done And now you're done. Almost done Stick it in its new home! Edit: I can happy report that it fits in an A2000 keyboard chassi as well, although you do have to cut away some of the plastic of the chassi that is holding the keyboard in place for it to fully close. Also, a little bit of the metal at the bottom of the keyboard was trimmed away for it to slide as far down as needed. Last edited by Turran; 11 April 2013 at 15:06.

08 April 2013, 15:09	#4
tesla Registered User Join Date: Nov 2012 Location: Vista, Calif Posts: 194	A side note ... I couldn't help but read your talk about the Mitsumi keyboard, because I am looking for parts for one, perhaps someone reading this can help. I have a Commodore SX-64, and the keyboard is a Mitsumi. One key mechanism was damaged. as a description, the key itself has two prongs with a small activation spring coming out of it, the two prongs attached to the key snap into a carrier with a large spring. The carrier itself also has two prongs, it snaps into two rectangular holes in the keyboards printed circuit board. I am looking for one carrier. Can anyone help? Thanks!

07 June 2016, 15:39	#6
spannernick Retro Nuts Join Date: Aug 2004 Location: London/UK Age: 53 Posts: 1,184	I know this is a old post but just wondered,if this works on a A4000,will this work on a Amiga CD32,I always wanted a keyboard for mine..? It looks simple to do,Thanks for sharing. Last edited by spannernick; 07 June 2016 at 16:10.

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08 April 2013, 09:51	#2
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Good job, the strain relief with the cable tie is also worth noting, soldered connections break so easily unless you tie the cables down near the joint.

08 April 2013, 12:05	#3
Turran Moderator Join Date: May 2012 Location: Stockholm / Sweden Age: 49 Posts: 1,571	Oh yeah. I'll add a note on that.

08 April 2013, 17:14	#5
TjLaZer Registered User Join Date: Sep 2004 Location: Tacoma, WA USA Age: 52 Posts: 1,915	Awesome work, thank you for documenting it for us!

07 June 2016, 16:54	#7
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Yes, it will work in a CD32.

08 June 2016, 00:36	#8
spannernick Retro Nuts Join Date: Aug 2004 Location: London/UK Age: 53 Posts: 1,184	So the connector is a PS/2 connector like on my PC..?

08 June 2016, 10:12	#9
idrougge Registered User Join Date: Sep 2007 Location: Stockholm Posts: 4,332	Yes.

24 June 2016, 16:24	#10
Turran Moderator Join Date: May 2012 Location: Stockholm / Sweden Age: 49 Posts: 1,571	I bought a few PS/2 male to PS/2 male cables on Elfa. Cut them in half and I have cables for 2 keyboards =)

15 September 2017, 22:46	#11
ElectroBlaster Junior Member Join Date: Mar 2002 Location: Exeter, Devon, UK Age: 49 Posts: 1,705	Do you have to use a ps2 cable? Can you not just re-use the original cable?

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