Ever since I completed work on the tiny retro system, it has displayed a peculiar habit of not booting after being disconnected from the mains for any length of time. At first I attributed this to the CMOS battery, but after swapping the battery three times. I had to conclude something else was a foot.
After consulting with various friends who hold a better grasp of electronics. I came up with a theory, which some agree with and others are less convinced about.
The LED PCB which I salvaged from a cycle light, is what drives the LED array on the front panel. Designed to run from 3xAAA batteries. I couldn’t help think the LED’s where some how continuing to draw power after the system was shut down. The only remaining source being the 3v CMOS battery.
Because the the regulator I built to drop the 5v feed to 2.88v is very simple. I can’t help but speculate that nothing is preventing the LED’s from continuing to draw power. Imagine a torch if you will, when switched on, the bulb will continue to illuminate until the source of power (batteries) has been depleted.
When the Nomad is told to shut down, the system does so. However the LED PCB is independent of the motherboard, in all but drawing power from a molex power connector. So the circuit is essentially open, just the power has been cut, so the lights go out.
As I said before, this is a working theory, which could be wrong and the motherboard itself could be to blame. So in an effort to fix the problem, I have rigged a CMOS jumper reset switch on the rear of the case.
Now when ever the system fails to boot, I no longer have to remove the lid to access the CMOS Reset jumper. I simply press the button on the rear. Now why dont they fit this to modern computers! 😛