A600 keyboard problem

Jope · 12 July 2006, 21:17

Ho!

Recently received an A600 in the mail, not really padded at all and it came from the UK to Finland.. :-)

So it's a bit battered, but it boots and reads floppies. However what it doesn't do is accept keyboard input.

The caps lock led lights up and stays on but nothing else happens.

I checked out the motherboard near kbd controller and it gets the right voltages + the data and clock lines are not short circuited, also all keyboard-related components that are in the schematics seem to work ok. I don't have a scope so I can't check the oscillator, however.

Anyone had to diagnose this before? All I can think of is that the kbd controller is fried and this theory seems to be supported by the fact that it runs very hot to the touch. :-)

Has anyone seen that a broken CIA would give these symptoms?

BippyM · 13 July 2006, 15:47

I don't think a CIA has alot to do with the keyboard..

I only have experience on the a500 keyboard cpu and that was a little bleeder for constantly packing up! I had 2 new keyboards for my 500 before it was sold and that keyboard was faulty too!

I'd assume the 600 has a similar KB controller as the 1200 and I've never had an issue with these!

Jope · 13 July 2006, 22:05

The A600 has the same kbd controller as the A1000/500/2000/3000/4000.. It supports multi key rollover properly, unlike the A1200 controller.

The keyboard data and clock lines go to the same CIA that handles the parallel port. Take a look at the schematics. :-)

Charlie · 14 July 2006, 01:07

@ Jope:
Bad luck - usually these old computers can take a lot of abuse.

I once rolled a Vauxhall Chevette estate on the way back from university for holls...
The car wound up upside-down in a ditch, my Acorn A3000 ( physically much like an A600 ) on the opposite side of the road.
Both worked fine, if a little beaten-up, once I got them home!

Sorry, not much help - just a poor excuse to reminisce...

Hopefully it's just a 'poped' keyboard ribbon connector. I've had abused computers behave much like yours despite the connector seeming to be properly seated.

Jope · 14 July 2006, 05:53

I have now a parts machine with another keyboard, but as expected it's keyboard produces the exact same symptoms.

After all, the old keyboard is not short circuited in any way and the ribbon cable contacts are still intact.

Besides, the keyboard mechanism itself is just a passive component, a bunch of switches. All the intelligence is in the keyboard controller, which is on the motherboard in the A600/1200.

I'll have to go to our other office at work where there's an SMD station I can use.. Then I'll pop out all the chips from the spare mobo and replace the kbd controller + CIAs with sockets for my main mobo. :-)

thomas · 14 July 2006, 10:35

If the CIAs are socketed, try to swap them. Then the keyboard should work but the serial port not. (BTW, the keyboard goes into the serial port of the CIA, not the parallel port). If the CIAs are soldered, you have a problem.

Jope · 14 July 2006, 12:10

Quote:

Originally Posted by thomas

If the CIAs are socketed, try to swap them. Then the keyboard should work but the serial port not. (BTW, the keyboard goes into the serial port of the CIA, not the parallel port). If the CIAs are soldered, you have a problem.

By parallel port CIA I meant that it's the same CIA chip that's connected to the Amiga's parallel port.

And yes, everything's soldered onto my motherboards.. I've got to get to the SMD station soon.

Jope · 16 July 2006, 11:37

It was the keyboard controller that was fried.

I wired an A500 keyboard directly to the motherboard and that works ok. (except for caps lock, I think this keyboard is a bit broken too. :-)

Keyboard reset also works by wiring the A500 keyboard's kbreset line to the A600's reset plane. :-)

I think I'm going to hide this A600 in some industrial enclosure.. Just a reset switch + leds on top and all the ports sticking out from the rear. (also joy/mouse).

Perhaps also build in a ps2 keyboard adapter.

BippyM · 16 July 2006, 13:27

going slightly off-topic..

Is there a way to create a reset switch for the 1200?

I want to add a reset as my keyboard doesn't support resetting :/

If so how/where do I solder?

Jope · 16 July 2006, 13:41

Add the switch between ground and any chip's reset pin.

http://de4.aminet.net/hard/hack/1200ExKb.lha

Check out the illustration of U13 in the text file for an example.

BippyM · 16 July 2006, 13:53

That looks fiddly..

So basically I connect a wire to the KBreset pin and another wire to the ground pin on the floppy controller?

Hmm.. Might be easier to solder a connector to the wires and then connect the tower reset line to it..

Jope · 16 July 2006, 20:55

Yeah, the kbreset pin is in turn connected to reset on the CPU, on the custom chips, etc.

So any reset is ok, that was the first document I thought of.. And of course there's plenty of ground to choose from.

A pin grid is a good idea, then you can easily remove the motherboard later if need be.

I personally like using PLCC sockets that are flipped upside down and plugged over the chips. Just solder the wires to the feet of the socket. (the kbd controller is bound to have a ground connection too, look at the schematics)

12 July 2006, 21:17	#1
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	A600 keyboard problem Ho! Recently received an A600 in the mail, not really padded at all and it came from the UK to Finland.. :-) So it's a bit battered, but it boots and reads floppies. However what it doesn't do is accept keyboard input. The caps lock led lights up and stays on but nothing else happens. I checked out the motherboard near kbd controller and it gets the right voltages + the data and clock lines are not short circuited, also all keyboard-related components that are in the schematics seem to work ok. I don't have a scope so I can't check the oscillator, however. Anyone had to diagnose this before? All I can think of is that the kbd controller is fried and this theory seems to be supported by the fact that it runs very hot to the touch. :-) Has anyone seen that a broken CIA would give these symptoms?

14 July 2006, 01:07	#4
Charlie . . Mouse . . Join Date: Jun 2005 Location: Nowhere Age: 55 Posts: 1,792	@ Jope: Bad luck - usually these old computers can take a lot of abuse. I once rolled a Vauxhall Chevette estate on the way back from university for holls... The car wound up upside-down in a ditch, my Acorn A3000 ( physically much like an A600 ) on the opposite side of the road. Both worked fine, if a little beaten-up, once I got them home! Sorry, not much help - just a poor excuse to reminisce... Hopefully it's just a 'poped' keyboard ribbon connector. I've had abused computers behave much like yours despite the connector seeming to be properly seated. Last edited by Charlie; 14 July 2006 at 01:18.

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13 July 2006, 15:47	#2
BippyM Global Moderator Join Date: Nov 2001 Location: Derby, UK Age: 48 Posts: 9,355	I don't think a CIA has alot to do with the keyboard.. I only have experience on the a500 keyboard cpu and that was a little bleeder for constantly packing up! I had 2 new keyboards for my 500 before it was sold and that keyboard was faulty too! I'd assume the 600 has a similar KB controller as the 1200 and I've never had an issue with these!

13 July 2006, 22:05	#3
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	The A600 has the same kbd controller as the A1000/500/2000/3000/4000.. It supports multi key rollover properly, unlike the A1200 controller. The keyboard data and clock lines go to the same CIA that handles the parallel port. Take a look at the schematics. :-)

14 July 2006, 05:53	#5
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	I have now a parts machine with another keyboard, but as expected it's keyboard produces the exact same symptoms. After all, the old keyboard is not short circuited in any way and the ribbon cable contacts are still intact. Besides, the keyboard mechanism itself is just a passive component, a bunch of switches. All the intelligence is in the keyboard controller, which is on the motherboard in the A600/1200. I'll have to go to our other office at work where there's an SMD station I can use.. Then I'll pop out all the chips from the spare mobo and replace the kbd controller + CIAs with sockets for my main mobo. :-)

14 July 2006, 10:35	#6
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 6,995	If the CIAs are socketed, try to swap them. Then the keyboard should work but the serial port not. (BTW, the keyboard goes into the serial port of the CIA, not the parallel port). If the CIAs are soldered, you have a problem.

16 July 2006, 11:37	#8
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	It was the keyboard controller that was fried. I wired an A500 keyboard directly to the motherboard and that works ok. (except for caps lock, I think this keyboard is a bit broken too. :-) Keyboard reset also works by wiring the A500 keyboard's kbreset line to the A600's reset plane. :-) I think I'm going to hide this A600 in some industrial enclosure.. Just a reset switch + leds on top and all the ports sticking out from the rear. (also joy/mouse). Perhaps also build in a ps2 keyboard adapter.

16 July 2006, 13:27	#9
BippyM Global Moderator Join Date: Nov 2001 Location: Derby, UK Age: 48 Posts: 9,355	going slightly off-topic.. Is there a way to create a reset switch for the 1200? I want to add a reset as my keyboard doesn't support resetting :/ If so how/where do I solder?

16 July 2006, 13:41	#10
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	Add the switch between ground and any chip's reset pin. http://de4.aminet.net/hard/hack/1200ExKb.lha Check out the illustration of U13 in the text file for an example.

16 July 2006, 13:53	#11
BippyM Global Moderator Join Date: Nov 2001 Location: Derby, UK Age: 48 Posts: 9,355	That looks fiddly.. So basically I connect a wire to the KBreset pin and another wire to the ground pin on the floppy controller? Hmm.. Might be easier to solder a connector to the wires and then connect the tower reset line to it..

16 July 2006, 20:55	#12
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,862	Yeah, the kbreset pin is in turn connected to reset on the CPU, on the custom chips, etc. So any reset is ok, that was the first document I thought of.. And of course there's plenty of ground to choose from. A pin grid is a good idea, then you can easily remove the motherboard later if need be. I personally like using PLCC sockets that are flipped upside down and plugged over the chips. Just solder the wires to the feet of the socket. (the kbd controller is bound to have a ground connection too, look at the schematics)

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