Atari 520ST+ keyboard problem and weird behaviour

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Factor6
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Atari 520ST+ keyboard problem and weird behaviour

Post by Factor6 »

Hi guyz,

I've noticed quite radical problem with my new (old) 520 ST+.
The problem is with keyboard. Keys LEFT SHIFT, A, S, F, H, B and N don't work at all.
I tried to disassemble keyboard but it seems to be in a very good condition, no visible issues.
Also, the cable and connector are ok. What could be wrong?

The second thing bears upon the firsrt problem, I guess. When pressing keys (those working ones),
Atari beeps. That's normal. But sometimes the beep sounds about 2-3 octaves lower, sometimes
it hangs with a longer tone, sometimes it doesn't beep at all. This occues only sometimes, not often.

Third problem is with floppy drive. Sometimes Atari don't recognize it's connected. I'm quite sure it's not
a problem with floppy (it's Cumana), I think it has some connection with the keyboard. When I tap or move
the keyboard a bit, it usually starts working. What does the chip on the keyboard exactly? Does it have something
to do with FDD?

Hmm, but main thing for me are those non working keys. Any ideas? Thanx.

F6
ATARI 520 ST+ (no-ROM-TOS), Cumana FDD, 130 XE 320K/stereo/QMEG, SDrive, SIO2SD, 2600jr, Jaguar
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wongck
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Re: Atari 520ST+ keyboard problem and weird behaviour

Post by wongck »

Factor6 wrote:The problem is with keyboard. Keys LEFT SHIFT, A, S, F, H, B and N don't work at all.
I tried to disassemble keyboard but it seems to be in a very good condition, no visible issues.
Also, the cable and connector are ok. What could be wrong?
My TT keyboard also acts similar, LSHIFT, CTRL, 2 & 4 don't work.
I traced the issue to my Mylar of the keyboard.
There are some small cracks in the silver linning and this cuts and breaks the cuircuit.
If you search the forum, some people says use conductive paint.
But I did not do that, instead I used my ST keyboard on the TT. :mrgreen:

Not sure if the 1st edition 520ST keyboard is like the TT using Mylar. :roll:
But it's something you can have a look at.
My Stuff: FB/Falcon CT63 CTPCI ATI RTL8139 USB 512MB 30GB HDD CF HxC_SD/ TT030 68882 4+32MB 520MB Nova/ 520STFM 4MB Tos206 SCSI
Shared SCSI Bus:ScsiLink ethernet, 9GB HDD,SD-reader @ http://phsw.atari.org
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Factor6
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Re: Atari 520ST+ keyboard problem and weird behaviour

Post by Factor6 »

Hoooray!

I found the problem. It was a microscopic crack on the keyboard PCB that interrupted two paths. Almost not visible by eye.
So I put there two short wires (thanx God there is no foil but PCB - Atari made good keyboards!), as you can see in the picture.
The keyboard works now and the FDD and beep problem is gone (which is strange).

Also, this helped a lot - could be handy for others:

http://www.flickr.com/photos/old_computers/3343072926

Yeeah!

F6
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ATARI 520 ST+ (no-ROM-TOS), Cumana FDD, 130 XE 320K/stereo/QMEG, SDrive, SIO2SD, 2600jr, Jaguar
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Re: Atari 520ST+ keyboard problem and weird behaviour

Post by wongck »

Factor6 wrote:Hoooray!

I found the problem. It was a microscopic crack on the keyboard PCB that interrupted two paths. Almost not visible by eye.

Also, this helped a lot - could be handy for others:

http://www.flickr.com/photos/old_computers/3343072926

Yeeah!

F6
Yeap, good for you. :thumbs:
It's the same failure mechanism th at we are seeing on the keyboard.

FYI, That flickr photo was put up by Techie-Alison who is a site admin of this forum :wink:
My Stuff: FB/Falcon CT63 CTPCI ATI RTL8139 USB 512MB 30GB HDD CF HxC_SD/ TT030 68882 4+32MB 520MB Nova/ 520STFM 4MB Tos206 SCSI
Shared SCSI Bus:ScsiLink ethernet, 9GB HDD,SD-reader @ http://phsw.atari.org
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Re: Atari 520ST+ keyboard problem and weird behaviour

Post by dexterslab »

once i get some conductive paint i'll do a how-to fix the TT/MSTE keyboard fault
simbo

Re: Atari 520ST+ keyboard problem and weird behaviour

Post by simbo »

also dont eat chips or crisps over the keyboard
as the acid in then dries out and it eats the copper tracks usualy shows as a small black dot on the copper print
even eats through the resist coating!!

lol:)
its worth throwing this in the mix
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wongck
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Re: Atari 520ST+ keyboard problem and weird behaviour

Post by wongck »

simbo wrote:also dont eat chips or crisps over the keyboard
as the acid in then dries out and it eats the copper tracks usualy shows as a small black dot on the copper print
even eats through the resist coating!!

lol:)
its worth throwing this in the mix
From what I sen, normally breaks along the lines where the plastics clamps on it. At least on mine is like that. I suspect it's more of the design.
My Stuff: FB/Falcon CT63 CTPCI ATI RTL8139 USB 512MB 30GB HDD CF HxC_SD/ TT030 68882 4+32MB 520MB Nova/ 520STFM 4MB Tos206 SCSI
Shared SCSI Bus:ScsiLink ethernet, 9GB HDD,SD-reader @ http://phsw.atari.org
My Atari stuff for sale - click here for list
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