[sdiy] lovely 'glitch' puzzle...siel DK600 74HC923 key matrix read

Bob Weigel sounddoctorin at imt.net
Wed Dec 28 07:29:51 CET 2011


On 12/27/2011 9:24 PM, Bob Weigel wrote:
> I found it I think.  Save your brains. lol. Somebody who apparently 
> wasnt' real sharp on reading components had put a 4.7 pf 3Kv cap in 
> next to the 40106 chip that typically rots out everything around it. 
> Because it was sandwiched in there I had to kinda look for it.  .047 
> uf is what it calls for there of course.  So that chip controls the 
> interrupt signal so it was doing something glitchy there and due to 
> the speed of the event probably my scope wasn't picking it up maybe.
>
Oh fiddle sticks... I put the right cap in and it appeared it was going 
to work right but then when I go to save the settings it glitches and 
rearranges the switch settings while hitting the buttons on the 
programmer.  haha.  Oh well I'm sure we're... close....these things can 
have so many issues they wear ya out.

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