Author Topic: "ghost" keypresses on cpc 6128  (Read 3128 times)

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Offline trabitboy

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"ghost" keypresses on cpc 6128
« on: 12:32, 18 September 13 »
Hello,
I recently had a terrible urge to ( at last, after 20+ years ) learn z80 ,
and port a very simple game of mine to it.


I got quite far developing on winape,
now before I integrate tricky stuff like "timing",
I thought I would need to pick up a real cpc 6128 to test my work.


Sadly, I could get an hxc to work on the machine I picked up,
but it has "ghost keypresses " in a random way ( sometimes a press every few seconds , sometimes doesn't stop typing, see screenshot )


I was wondering if any of you had encountered this problem,
and is there a fix ?








Offline Bryce

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Re: "ghost" keypresses on cpc 6128
« Reply #1 on: 13:27, 18 September 13 »
Most likely just dirt on the membrane and under the keys. Disassemble the keyboard, wipe the membrane with a soft cloth and warm water on a flat surface. Remove all the gunk from under the keys and it should work fine again.

Bryce.

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #2 on: 14:53, 18 September 13 »
Thank you!
Will try that next weekend.  ;)

Offline TFM

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Re: "ghost" keypresses on cpc 6128
« Reply #3 on: 20:30, 18 September 13 »
Good luck with the keyboard  :)


And welcome here btw  :) :) :)




I'm looking forward to read / see more about your game.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Offline Gryzor

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Re: "ghost" keypresses on cpc 6128
« Reply #4 on: 21:13, 18 September 13 »
Damn, Bryce, can you stop answering first to every question, even the simple ones others can answer as well? :D :D


Welcome, man, and good luck with that membrane and your game! Let us know!

Offline TFM

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Re: "ghost" keypresses on cpc 6128
« Reply #5 on: 22:02, 18 September 13 »
Damn right! And then he tells that he would be too busy to do a 4 TB RAM expansion for the CPC  :laugh:
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Offline Bryce

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Re: "ghost" keypresses on cpc 6128
« Reply #6 on: 11:26, 19 September 13 »
It's your fault Gryzor. since I got Tapatalk I can answer hardware questions in a taxi, waiting at the airport, sitting bored in yet another hotel. All places where I can't do much in the way of 4MB RAM expansions :(

Bryce.

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #7 on: 18:53, 19 September 13 »
thanks for the friendly welcome !  ;)
I eventually finish all my project ...
... even if they take many years !

Offline Gryzor

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Re: "ghost" keypresses on cpc 6128
« Reply #8 on: 21:03, 19 September 13 »
@Bryce: you mean you can't draw schematics on your knee, on a napkin or something? Come on!


@trabitboy: best of luck to you mate!

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #9 on: 13:17, 22 October 13 »
Hello!
Beware of a noob question :  :o

A few weeks back I attempted to open the keyboard ,
but I didn't understand how to unlock the ribbon cable from the motherboard ( see pic )
It look very fragile, and I remember on amigas, there was a small clip to move first before moving the ribbon.
Am I really supposed to just pull it?


Also, I'm still making progress on my noob assembly project,
and I don't know it is is "customary" here to do a progress topic
( a lot of these on cpc rulez for instance )
which section of the topic should it be in ?


Have a nice day !  ;)

Offline 00WReX

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Re: "ghost" keypresses on cpc 6128
« Reply #10 on: 13:34, 22 October 13 »
Yes, for the CPC 464 & 6128 simply slide / pull each ribbon out...there is no clip / lock.
For the CPC 664 there is a clip / lock type arrangement.

Cheers,
Shane
The CPC in Australia...
Awa - CPCWiki

Offline wilco2009

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Re: "ghost" keypresses on cpc 6128
« Reply #11 on: 14:16, 22 October 13 »

Additionally to clean the membrane, could be necessary to bend the membrane a bit, repeatedly to unstick the membrane contacts.

Sometimes some of the membrane contacts get stuck.

Offline Gryzor

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Re: "ghost" keypresses on cpc 6128
« Reply #12 on: 20:25, 22 October 13 »
Just make sure you're extra gentle with it and you'll be fine.


And yes, you're in the right place, please post away!

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #13 on: 11:09, 18 August 14 »
Hello,
I finally got around my fear of breaking the ribbon cables and took apart for the keyboard
to give it a good cleaning .
I noticed that :
- the amount of dirt was unbelievable.
- the double membrane seemed a bit sticky  :D ( so I tried to bend it gently a couple of times.

Upon re-assembly however,
the problem is still there .
Also only some keys seem affected ( the numer row  " # รจ (  and the left arrow key  ).

It seems attaching my home-made joystick also alters the random keypresses,
so I'm quite inclined to think it is more than the membrane .

Isn't the same chip driving the keyboard and the joystick port since they are both in the keyboard matrix ? ( noob alert  :o )

It's truly a shame, I couldn't refrain from using this machine since I got it from ebay one year ago ( gets used several times a week ),
but I still couldn't fix it .

Offline Bryce

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Re: "ghost" keypresses on cpc 6128
« Reply #14 on: 14:23, 18 August 14 »
I've just fixed a 6128 with exactly the same problem. IC101 (74LS145) had failed and was causing this.

Bryce.

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #15 on: 15:47, 18 August 14 »
I'll check if it is socketed .


Do you know where I can get one ?
Also, would you be interested in doing the repair work ? ( PM ? )


Thanks for the answer already :)

Offline CraigsBar

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Re: "ghost" keypresses on cpc 6128
« Reply #16 on: 16:06, 18 August 14 »
I'll check if it is socketed .


Do you know where I can get one ?
Also, would you be interested in doing the repair work ? ( PM ? )


Thanks for the answer already :)
tee hee hee. There is a waiting list for bryces time. :-)

Get in the queue ;-)
« Last Edit: 16:07, 18 August 14 by CraigsBar »
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Offline Bryce

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Re: "ghost" keypresses on cpc 6128
« Reply #17 on: 16:25, 18 August 14 »
It won't be socketed. As far as repairing, no problem, send it over it's a 5 Minute Job. You seem to be relatively local to me too.

@Craig: Your request is a little more complicated (Time consuming), which is why I needed to delay it. But you can send it over any time you like and I'll start it as soon as I can.

Bryce.

Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #18 on: 18:11, 18 August 14 »
Thank you very much,
PM it is then  8)

Offline CraigsBar

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Re: "ghost" keypresses on cpc 6128
« Reply #19 on: 18:22, 18 August 14 »
It won't be socketed. As far as repairing, no problem, send it over it's a 5 Minute Job. You seem to be relatively local to me too.

@Craig: Your request is a little more complicated (Time consuming), which is why I needed to delay it. But you can send it over any time you like and I'll start it as soon as I can.

Bryce.

Hehe I know, I was using the chance for some humour to mention that you are a very busy man. Like I said before I am in no real hurry. I have 2 working 6128 pluses at the moment and a x-mem to play with lol.
Craig.
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Offline EgoTrip

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Re: "ghost" keypresses on cpc 6128
« Reply #20 on: 19:09, 18 August 14 »
Hehe I know, I was using the chance for some humour to mention that you are a very busy man. Like I said before I am in no real hurry. I have 2 working 6128 pluses at the moment and a x-mem to play with lol.
Craig.


That's greeedy. You should let me have one of them.
EgoTrip's Stuff
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Offline CraigsBar

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Re: "ghost" keypresses on cpc 6128
« Reply #21 on: 19:22, 18 August 14 »

That's greeedy. You should let me have one of them.
my spare one (that is currently hosting the x-mem until Bryce has time to upgrade my 464plus) you would not want. It looks like it's spent an age with a 30 a day smoker it's so yellowed. Oddly the cm14 that came with it is still mostly white.

Craig
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Offline trabitboy

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Re: "ghost" keypresses on cpc 6128
« Reply #22 on: 13:37, 10 November 14 »
Hello,
my machine is back in full working order,
thanks to a repair from Bryce.


I wanted to thank him publicly for his patience and skill  :D


Good day to all!

Offline Bryce

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Re: "ghost" keypresses on cpc 6128
« Reply #23 on: 14:27, 10 November 14 »
Hello,
my machine is back in full working order,
thanks to a repair from Bryce.


I wanted to thank him publicly for his patience and skill  :D


Good day to all!

Hi trabitboy,
      no problem. Glad I could bring yet another CPC back to life :) Many happy hours with it.

Bryce.