Problems with 8/A Programmer's Panel

Charles charlesmorris800 at
Wed Sep 9 12:26:52 CDT 2015

>Not sure what you mean by membrane keypad. My front panels certainly
>have real buttons, which makes a clicking noise and feeling when I press
>them. But maybe I'm confused and there is some membrane behind the keys
>or something?

That's my mistake. I've never actually seen or touched a DKC8-AA panel, just 
pictures of them in the manual :)
Hoping to acquire one since I am trying to do other things with the 8/A than 
keep debugging its hardware! (such as getting Dumprest working for RL02).

>The 74f parts may be too fast. Try adding damping resistors (10 to 30 ohms) 
>in series with the outputs to slow things down or just switch to 74ls

Thanks for the tip. That is what I was implying, not sure I said so 
explicitly :)
But adding twelve resistors which may or may not fix the problem, and 
hacking up my board is not an attractive thought... but neither is changing 
three 20-pin unsocketed DIPs without proper desoldering equipment. Guess I 
should have used sockets in a prototype!
Besides, the board really does need redoing with proper power and ground 
plane management.


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