All, So, after resolving the serial port issue on that machine that I posted about last (replaced the 1604 UART), I declared victory and sent the machine back to Randy. However, he's now reporting that it has power/boot issues. Basically, if you power the machine off (either by switch or BASIC 'power off' command), you have to remove power from the system before you can turn it back on.
Since I don't have the machine anymore, diagnostics are somewhat difficult. And the behavior actually disappeared briefly, but has now returned apparently for good. Things to note about this machine: It has had the memory battery was replaced by a 1f supercap. It's also been "recapped" -- all done by the person from whom Randy acquired it. That person actually neglected to trim the legs on all the capacitors, so they were just mashed underneath the PCB and certainly shorting against each other and possibly other components. When I was working on it, I never experienced this issue - it's only shown up since I returned the machine to Randy. I gave the machine a pretty thorough burn-in before returning it to him (flashed the REX, loaded software from serial, ran basic programs, etc). He's done multiple cold-boots and left it connected to external power for a week now. Can anyone posit any theories as to what would cause this? Something in the power circuit? Thanks for any help on this, -Josh
