27 May 2018, 23:51 | #1 |
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A500 keys not working
Hello,
Recently bought a Amiga 500 Rev 6A from a old friend. I'm being trying to restore, but some issues come across. Some keys, specially bottom keys are not working: z,x,c,v,b,n,m, space, some cursor keys also. I've already cleaned up the membrane, at first sight seems no track compromised, any opinions out there ? thanks. Regards. Pedro Last edited by Vladdrac; 27 May 2018 at 23:58. |
28 May 2018, 02:53 | #2 |
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Check out ebay. https://www.ebay.com/itm/Connect-fav...kAAOSwT5xZOa-B
I bought this as a backup as my keyboard was bad when I bought my Amiga 500. I went and bought another membrane hoping that would fix the keyboard issues I was having. It did. But the membrane must have been bad as well. As it fixed some keys that didn't work before and it had other keys that didn't work. So then I bought a working keyboard off of ebay. But bought the circuit board as a backup. Works great with wireless keyboard. |
28 May 2018, 03:01 | #3 |
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You can purchase new keyboard membranes here:
https://www.sellmyretro.com/offer/de...Speed=noscript A membrane can be faulty without having any visible signs, if in doubt it's best to replace it or exchange the faulty one for a working keyboard. |
28 May 2018, 14:48 | #4 | |
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Quote:
Quite expensive for a membrana. |
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28 May 2018, 14:50 | #5 | |
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Quote:
Hi thanks for sharing, but I'm trying to keep my A500 most original as possible. |
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31 May 2018, 12:26 | #6 |
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Don’t forget the down button, question mark, period, and comma.
Anyway you have to trace continuity from the keyboard membrane back to pin 32 of the keyboard controller. |
31 May 2018, 13:46 | #7 |
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03 June 2018, 13:54 | #8 |
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Hi Does anyone knows where is the pin 32 on the keyboard controller ?
thanks |
03 June 2018, 14:04 | #9 |
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When you look a the big chip on the back of the small keyboard controller PCB, the dot in the corner of the chip is pin 1, and you count pins counter-clockwise from there.
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03 June 2018, 14:07 | #10 |
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If any of those other keys I mentioned actually work, then the break in in the membrane in the same row between a working one, and the first non-working one (and not in the ribbon cable part or on the PCB).
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04 June 2018, 00:08 | #11 | |
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Quote:
I is this correct? In order to perform continuity test must the motherboard connect be in place ? I'm totally lost, any help will be much appreciated Regards |
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04 June 2018, 09:33 | #12 |
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Dot is the half moon dimple on the left hand side of the chip.
You start counting the pins above the letter T in Mitsumi towards the right. That is pin 1. To its right is 2 3 4 5 6 etc. Once you reach the end of the chip (above where it says C12), you jump to the top right corner of the chip and continue counting from that pin towards the left. |
04 June 2018, 09:36 | #13 |
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Awesome thanks for the explanation, Ill test it later.
Regards Last edited by Vladdrac; 04 June 2018 at 16:44. |
04 June 2018, 23:17 | #14 |
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So I've tried to track from pin 32 to some keys that are not working, but nothing happens.
Then I've tried other working keys, and nothing happens too, what am I doing wrong ? I'm trying to measure continuity from the pin to a set of a key. With a multimeter I've put one cable to the pin and one to one of the set of key. Last edited by Vladdrac; 05 June 2018 at 18:15. |
06 June 2018, 09:08 | #15 |
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Anyone??
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06 June 2018, 09:29 | #16 |
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I really don't get what kind of help you now need..
Look at how the traces go, follow the traces, identify the contact points along that trace, measure each part of the trace between the two nearest contact points, find the broken part and fix it. |
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