@bateske - Thanks for the offer to sort this out via the contact page - I may end up having to take you up on that, but part of the fun is the adventure of figuring out what is wrong.
I had time to take it apart and get some data. Sorry the pictures are a bit fuzzy…
I can confirm, that after leaving it plugged in to my PC to charge - the red charging light stayed on all day/night. It never went out.
Measuring the voltage across the battery tabs on the back, I get a tiny bit more than 3V. This is probably not good, as the battery is supposed to be 3.7 – so I’m thinking that there is something wrong with the charging circuit.
I checked the continuity on the power switch. As pictured it is off (looking at the front, the switch is to the far left). When you move the switch to the right - I was able to measure connectivity between the two pins on the right bottom side of the switch. Switching off - disrupted that connection. So I’m fairly confident that the power switch is working.
Same for the reset button. I measured on the left and right sides of the reset button, and was able to detect connectivity when I pressed the button.
Now’s where things start to get a bit random - because I didn’t have in front of me a schematic for the board, so I was just poking around (carefully).
Adding a USB cable to a wall wart, I measured 4.97V coming in between the shell of the connector (ground) and just below the lit up red led that indicates charging. No surprise here.
I was able to measure 4.97V between the usb shell (ground) and the R5 (resistor) just above the USB connector in the front image. I thought this was a bit odd, but I guess the chip will work with 3v or 5v?
I decided to see if I could track down the power pins on the “cpu” itself. I kept the black probe on ground (USB connector shell) and carefully dragged the other red probe across the pins. If we think of the CPU as a diamond shape, about mid-way across the lower left side - I touched something that caused the Arduboy to come to life!
It was very temperamental, I mis-touch on another pin and it’d turn itself off again. I did have it running for a few seconds with nothing touching the device… then it would power off (or the screen would go). I even had sound and button presses working for a brief time.
Looking here - if this is the right data sheet - http://ww1.microchip.com/downloads/en/DeviceDoc/2503S.pdf I’d guess I hit Vcc or Reset?
No matter what I did, I wasn’t able to measure any voltage on the power switch from the battery (-) to the switch. Maybe I should have tried from battery (+) to the switch?
Looking at the back of the device, I was again - randomly poking around. I measured from the (-) batt connection to the lower left D15 CLK test pad. Here I got 2.7V - (no USB cabled plugged in). So I have a suspicion that the battery is not charging - and this is at least part of my problem.
Of course, I can’t seem to find my other (working) Arduboy for comparison at the moment.
So where does this get me?
- Charging seems to be broken. Long periods of time plugged in to charge, and the light never goes off and the battery only reads a bit over 3V
- Plugged into USB power, the device doesn’t work (I think it’s supposed to work right?)
- I was able to see it working normally for a brief time (after I reset the CPU?)
So - any thoughts out there for specific experiments / tests I can perform here?