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Author Topic: A500 keyboard membrane - pc kb adapter built (help)  (Read 3930 times)

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Offline odiousTopic starter

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A500 keyboard membrane - pc kb adapter built (help)
« on: August 25, 2007, 06:50:43 PM »
Hi,

Where to get a replacement or how to repair them?

I'm using liquid silver to restore some broken traces but it's not working.

I once saw someone repairing a membrane using a mixture of graphite (powder scratched from a pencil) and glue but i have tried this before without any results.

Is there any adapter for a pc keyboard that is easy to build and doesn't need software on the amiga?

Any help is appreciated.
 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #1 on: August 25, 2007, 08:41:09 PM »
Funny enough i used a toothpick too. I've repaired a couple of keys but i found out that there are a lot more of them. The traces over the square holes at the plate beneath the membrane are oxidyzed and break easily.

There are also traces broken beneath "bridges" (where traces cross over others) that i cant access. Unfortunatelly i will have to go in another direction.

I wish they had made the kb with a pcb. Quite chronical as i have seen some with non working keys. :(

 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #2 on: August 28, 2007, 05:17:17 AM »
Great. I'll definitely build this. I have one doubt though: What kind of ic is the 7407 ?
 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #3 on: August 30, 2007, 10:35:36 PM »
I got an LS. What is so special about those military version chips? Are they less prone to faults?

 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #4 on: September 08, 2007, 04:44:17 AM »
Ok, I have built the board but i could only get 16F84A instead of the obsolete 16c84.

I asked a friend to program the pic and when trying to program it, he got an error. So he changed something to accept the 16f84A instead of the 16c84. He warned me it might not work and so it didn't.

I double checked all the connections and no key works at all, only the num lock led lits on/off when the num lock key is pressed.

I looked at the pinouts of the pics and they are the same but my knowledge on this stops there.

Any help would be appreciated.
 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #5 on: September 10, 2007, 03:25:26 AM »
Don't be shy :)
 

Offline odiousTopic starter

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Re: A500 keyboard membrane
« Reply #6 on: September 10, 2007, 05:36:31 PM »
The problem is not having not access to a programmer.

The real problem is that the .hex on those designs are for 16C84 and will not work directly on 16F84 nor 16F84A.

The code has to be assembled to work on 16F84's and i don't know how to do it.

Cheers.