Flakey memory power switch? On Sat, Sep 8, 2018, 2:42 PM Josh Malone <josh.mal...@gmail.com> wrote:
> 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 >
