That diode appears to have been mismarked or is defective.
Do you have the one you originally pulled from the board?
If so, do the same with it.
Do you have the one you originally pulled from the board?
If so, do the same with it.
Why 10.4v instead of 12v?
Here's the problem. There is no information on the threshold for the input to the MCU. I'd like to see it up around what you'd get from the 5.1v Zener diode but... The zener is breaking down at a lower-than-expected voltage. I might believe 4.9v but not 3.9v and 3.6v is even more strange.
Your meter seemed to read correctly when you checked the supply voltage for the MCU.
Here's the problem. There is no information on the threshold for the input to the MCU. I'd like to see it up around what you'd get from the 5.1v Zener diode but... The zener is breaking down at a lower-than-expected voltage. I might believe 4.9v but not 3.9v and 3.6v is even more strange.
Your meter seemed to read correctly when you checked the supply voltage for the MCU.
At 12v replacement diode shows 3.7v
Original diode shows 4v
Power supply wouldn’t give me over 10v before for some reason, not sure why
Original diode shows 4v
Power supply wouldn’t give me over 10v before for some reason, not sure why
I think you'll have to find another source of Zener diodes. If you order from DK or Mouser again, order the diodes.
It should be easy enough to check one of the new zener diodes out of circuit by attaching it to the lab power supply with a sensible dropper resistor in series (10k or whatever) - cathode towards resistor, anode on power supply (-) out.
Without soldering anything at all, one could also put a finger on the zener in operation... if it stays stone cold, chances are there is something in parallel to it that's drawing too much current. A leaky electrolytic would be a prime candidate, for example...
Without soldering anything at all, one could also put a finger on the zener in operation... if it stays stone cold, chances are there is something in parallel to it that's drawing too much current. A leaky electrolytic would be a prime candidate, for example...
That is sort of what I did with the 47k resistor, also shame I didnt think to order the diodes when I ordered the fets for my amp
Should I try and find a diode that reads only 5.1v with the resistor or can I try 5.1v or over?
I wouldn't want it to be greater than 5.1v but it should be very close to 5v, especially with the series diode bypassed.
You could also try connecting the 5v regulator supply voltage (confirm that it's at 5v) to that pin through a resistor (1k). If that doesn't bring the input up to 5v, I think the MCU may be defective.
You could also try connecting the 5v regulator supply voltage (confirm that it's at 5v) to that pin through a resistor (1k). If that doesn't bring the input up to 5v, I think the MCU may be defective.