I got a M100 off craigslist recently. In the parking lot it powered up with new batteries (old ones in it literally crusty). When I got it home, it powered on but after a few seconds the display just faded out, and it won’t power back on unless I wait several hours, then it does the same brief power on/fade away thing. I cleaned all the battery contacts and tried an external power supply, no change. I opened it up and found the Nicad battery starting to leak, but no corrosion damage on board yet. I unsoldered the backup battery and ordered a replacement. Should a M100 be able to power up at all without the backup battery? I temporarily installed a random 5v super cap I had on hand and now it does the same start+fade away thing. None of the existing caps looked visibly damaged or leaking.
Any idea where to start troubleshooting?
