In all of the prototype PCBs Mike has ever done, they have all worked, with one exception - that the AXP209 needed a solder blob underneath to get the exposed pad to make contact with the PCB, which then worked perfectly fine. That was all sorted out in the last revision. That same PCB with the exact same set of components was a 100% success in its prior run of quantity ten, before Mike’s long-standing manager quit unexpectedly.
On this new set of PCBs, the output from the 3.3 V power regulator, which should be a SY8008B, is only 0.5 V. This is a first. There’s no way to find out why that is, except to ask Mike to buy some replacement SY8008B SOT23-5 ICs and send them to me, here in Taiwan. The SOT23 IC is so small they cannot put markings on it, so we do not have any way of knowing if the supplier sent Mike the right one. The only option: buy some more and replace them.
Unfortunately, with no “money available for living expenses” from the remaining EOMA68 budget, I am going to have to go to Canada on the 10th of October, and will be there until December. I will take some of these boards with me: there is the off chance possibility of encountering a workshop with a solder station and/or being able to source SY8008B ICs there if the ones from Mike do not arrive in time.
In addition, even if the faulty parts are replaced, there is no guarantee that there is not something else. This is just how it is. This is how it goes, one thing at a time.
I wish that there was a magic deep financial pocket where other people could be paid to do this work, with all the resources and equipment on hand they’d ever need. The entire project would have been done within six months or less, with a USD 500,000 and above budget, completed two years ago and moving on to faster processors.
As it is, we will get there, it just takes longer.
Update: My friend Adam happened to be in Huaqiangbei last night when I contacted him - he is going to the markets this morning to buy 50 SY8008B regulators, and will send them to me when he returns to Hong Kong.