A500 Keyboard problem (sequences of chars from arrow keys)

boksajak · 06 December 2020, 22:51

Hi all,

I have a problem with the Amiga 500 I bought - pressing the arrow keys generates sequences of some characters. It's always the same sequence for each arrow key. E.g. right arrow results into sequence... \=-0987654321 ...see picture. Caps lock also gets toggled on some presses.

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Have anyone seen this issue before? Is it fixable? So far I tried swapping the keyboard with another and it went away, so I think it must be faulty keyboard controller... but all other keys seem to work fine. Any help is appreciated.

solarmon · 06 December 2020, 23:56

It would be interesting to see how this issue manifests itself in the Amiga Test Kit keyboard test.

Jope · 07 December 2020, 10:04

I'm also guessing a faulty keyboard controller, with the row bits stuck. Do you get some sequence when pressing numpad minus? Pushing help would go through all the function keys.

Here's the matrix, and the Amiga keyboard controller reads the columns starting from 0 and incrementing from there.
http://amigadev.elowar.com/read/ADCD.../node017A.html

One thing that popped into my mind: does your keyboard have the plastic insulation in place and is it still intact? Have you tried with the keyboard in your hand so that it isn't touching any metal shield or floppy drive case?

solarmon · 07 December 2020, 10:46

Also, use a multimeter and microscope to check for any dry joints and shorts on the pins of the keyboard controller.

As jope already said make sure that the back of the controller board is insulated and not shorting in the metal shield.

boksajak · 08 December 2020, 18:29

thanks solarmon and Jope, good suggestions!

Looks like all keys including the minus on numpad that belong to column 0 are malfunctioning. I inspected the board and it looks fine, but it also looks like someone was already tinkering with it. It's a bit scratched and one screw is missing.

This is the second Amiga in "top state" I bought that's toast :/ Luckily I managed to assemble a single working one from these two.... what is wrong with people...

So I believe that 6570 controller is dead. Replacements go for 40-50€ on Ebay. That's too much - is there maybe some other option?

Btw. I don't have means to transfer Amiga Test Kit from PC onto floppy yet, I'd like to get Gotek soon-ish. I've never had Amiga yet, just C64/128.

Jope · 08 December 2020, 19:42

Jens has them in his shop too for 27 euro.

https://icomp.de/shop-icomp/en/shop/...-6571r6pd.html

06 December 2020, 22:51	#1
boksajak Registered User Join Date: Dec 2020 Location: Ulm/Germany Posts: 2	A500 Keyboard problem (sequences of chars from arrow keys) Hi all, I have a problem with the Amiga 500 I bought - pressing the arrow keys generates sequences of some characters. It's always the same sequence for each arrow key. E.g. right arrow results into sequence... \=-0987654321 ...see picture. Caps lock also gets toggled on some presses. Have anyone seen this issue before? Is it fixable? So far I tried swapping the keyboard with another and it went away, so I think it must be faulty keyboard controller... but all other keys seem to work fine. Any help is appreciated.

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06 December 2020, 23:56	#2
solarmon Registered User Join Date: Dec 2018 Location: UK Posts: 1,716	It would be interesting to see how this issue manifests itself in the Amiga Test Kit keyboard test.

07 December 2020, 10:04	#3
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,952	I'm also guessing a faulty keyboard controller, with the row bits stuck. Do you get some sequence when pressing numpad minus? Pushing help would go through all the function keys. Here's the matrix, and the Amiga keyboard controller reads the columns starting from 0 and incrementing from there. http://amigadev.elowar.com/read/ADCD.../node017A.html One thing that popped into my mind: does your keyboard have the plastic insulation in place and is it still intact? Have you tried with the keyboard in your hand so that it isn't touching any metal shield or floppy drive case?

07 December 2020, 10:46	#4
solarmon Registered User Join Date: Dec 2018 Location: UK Posts: 1,716	Also, use a multimeter and microscope to check for any dry joints and shorts on the pins of the keyboard controller. As jope already said make sure that the back of the controller board is insulated and not shorting in the metal shield.

08 December 2020, 18:29	#5
boksajak Registered User Join Date: Dec 2020 Location: Ulm/Germany Posts: 2	thanks solarmon and Jope, good suggestions! Looks like all keys including the minus on numpad that belong to column 0 are malfunctioning. I inspected the board and it looks fine, but it also looks like someone was already tinkering with it. It's a bit scratched and one screw is missing. This is the second Amiga in "top state" I bought that's toast :/ Luckily I managed to assemble a single working one from these two.... what is wrong with people... So I believe that 6570 controller is dead. Replacements go for 40-50€ on Ebay. That's too much - is there maybe some other option? Btw. I don't have means to transfer Amiga Test Kit from PC onto floppy yet, I'd like to get Gotek soon-ish. I've never had Amiga yet, just C64/128.

08 December 2020, 19:42	#6
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,952	Jens has them in his shop too for 27 euro. https://icomp.de/shop-icomp/en/shop/...-6571r6pd.html

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