Hi Lee,?
I will try your suggestion. I have the front panel on my breadboard now with your suggestions for testing. Have a safe trip, when you are back we can reconnect for troubleshooting.
Thanks,
You're the second person to mention problems with the "8" key. I haven't seen it myself, and from the schematic, can't imagine what could be wrong that only affects the "8" and not the other keys in the same row.
The only thing that's changed recently is that the 15Kx4 SIP was changed to 18Kx4 (because the 15K was out of stock). It works the same on my Z80MC, but maybe some 74LS145's have excessive off-state leakage that 18k won't pull up? An easy test would be to try adding a resistor in parallel with the 18K (like 22K) to see if that helps?
Lee
--
Excellence does not require perfection. -- Henry James
But it *does* require attention to detail! -- Lee Hart
--
Lee A. Hart
-----Original Message-----
From: <[email protected]>
Sent: Mar 23, 2025 8:11 PM
To: <[email protected]>
Subject: Re: [Z80MC] Micro BASIC Manual
It's funny you mention a problem with the #8 button. I have a similar problem with mine. Instead of getting 8, I get 9.
Spent a bunch of hours troubleshooting. Never figured it out.
Sometimes it will produce an 8.
If I do E 2888, I get 2899.
If I do E 7888, I get 7899.
And so on.
Maybe we should start a new thread...
Mitch
Kerem Kapkin