(A500+) more keyboard problems

[sim085]

Hi,

I already had another thread on my A500+ keyboard. However things have taken a bad turn it seems.

When I switched my A500+ after a long time I realised that the keys CTRL+AmigaL+AmigaR where not restarting my machine. However as much as I remember all keys worked fine when not in that combination.

After that I once plugged in my joystick while the machine was turned on. Something must have happened then. The CTRL+AmigaL+AmigaR worked once. Then when the machine re-booted and tried again the Capslock button would no longer work for a few seconds and then again it would start to work. The CTRL+AmigaL+AmigaR never worked again (but my joystick has no problems).

I then shelved the concerns I had on my keyboard while I started buying new equipment for my machine. Yesterday I decided to look back into the issue. However now I noticed that the ShiftL and AmigaL keys do not work.  

I do not know what the problem might be. However before this I had confirmed that the transistor responsible for reset was not working.

Does anyone have any idea what I need to do... I can buy a new keyboard but I prefer if I could fix what I have already - I had to have to throw anything Amiga ... even when it does not work!

[sim085]

Lockon_15 wrote:
Left Shift and left Amiga key could share same bus contact and perhaps if their common trace is damaged, that could be the reason for that local malfunction.
Dissasemble keyboard in pieces and try to take a look at thin black traces on both inner parts of keyboard matrix. Sometimes an excess dirt could cause printed conductive trace to lift-off and thus result in defect of more keys together.

I will try to do this. So do I have only to clean where I see dirt? Additionally, from what do I determine if a trace is damaged or not?

Lockon_15 wrote:
Did you replace that dead transistor ?
IMHO, both of those on that small PCB can be replaced with 2N3904 or maybe 2N 3906, not sure exactly which type is (NPN or PNP).

I still did not do this because I need my cousin for this since I do not have any experience with soldering. I was going to try and find those transistors from a local store.

[sim085]

if parts of the trace is damage, missing or got moved to opposite foild then what do I do?

[sim085]

Thanks, I'll try to open the keyboard this evening and see what the problem might be!

[sim085]

I opened the keyboard. There was some dirt cleaned it. Closed it again, but the Amiga-Left, Shift and Ctrl still do not want to work!! I checked the lines but did not see anything strange! Is there any other parts of the keyboard that could creating this problem? If not then I might considering ordering just the membrane of the keyboard!

[sim085]

Sorry to bring this up again, but; if it is not the membrane then could it be something else?

[sim085]

Thank you I will try to use a multi-meter to see if there is any damage to the membrane. Thanks for now

[sim085]

Hello again,

I still did not confirm if the problem is with the membrane. However if so then could I just buy the membrane of an A500 keyboard rather then waiting for an A500+ one? or?

Regards,
Sim085

[sim085]

There are plenty of A500 keyboards on ebay but I none of the A500+. Can I just buy an A500 keyboard and use it's parts for my A500+ one? Or is there any other place from where I can buy an A500+ keyboard?