Differences between the original 312 power supply chain and the MK312BT


#1

In an effort to try and resolve my Failure 20 and 21 errors (see separate posting) I went back to my own original Erostek 312 box which comes with a 12v 800ma power supply.
If I plug this into my MK 312 BT Box I get a Failure 20 error which I “assume” is that it is not man enough to drive the modified power supply design.
The mains PSU that is giving me Failure 21 is an 18v 2200ma unit.
So can anyone enlighten me as to the power supply design differences between the original Erostek unit and the MK 312BT and where they converge to supply the various chipsets at the voltages they expect
Alternatively is it possible to tweak the POST routine of the code to either disable checking or check a sightly different value that may be in spec


MK-312BT BOM Error
#2

There’s only a very minor difference between the power supply design of the the original Erostek and the MK-312BT.
I can charge the MK-312BT with an old Erostek power brick (12V 500mA) without any issues.
I suspect you have a short circuit (check solder pads, especially near U14) or a bad/wrong resistor somewhere.


#3

Thanks for replying 2 of us have been through the installed parts list and checked the soldering - we’ve also tested the voltage output by each of the regulators and they are in spec.
It would be really helpful for all those building the unit to have a set of test points and voltages so we can check things as we go along rather than just “hoping” things will work. I’d like to build another one once I know how to debug this one


#4

Did anyone find a solution for bug 20?
I checked all the voltage sources. I checked and recalculated the voltage divider processor. I compared the original scheme with the MK-312BT V1.3 and there are only minor minor differences in the power supply. I tried replacing the battery with a laboratory source. Nothing helped me.