Apologies for my first post being a request for help but I’m properly stumped with this one.
As the title says, the switch won’t charge nor power on - The caps around pi3usb and mt92xxI appear to be fine (as in no shorts) but I did notice that some of the caps under the board appear to be shorted to ground - I found a post on here by Calvin that said to check them in diode mode and all were fine except these three, the resistance to GND is 0.03 across all…
Can’t yet post pics - Will update when i can
I was then reading some more threads and came across SheriffBuck’s guide to testing the power rails, here are my results…
|3v3|340|
|1v8|13.51|
|SYS|1.06Mohm|
|1V35|15.9|
|1v15|0.3|
|1v15|1050|
|0v8cpu|391|
|0v8gpu|69|
|Joycon|3.3|
I mean I am not an expert but those numbers don’t look good to me
So, I have to admit that I am a complete n00b here and all of the above may be completely irrelevant but any help would be gratefully appreciated.
Can you confirm if your meter is auto ranging or manual ranging?
If this is truly ohms then that’s likely the primary fault pulling down a few of the other rails you measured, I’m not familiar with the testpoints that @SheriffBuck is using for these rails as I’m usually measuring directly on the output inductors for the PMIC rails (and there is two rails with a very close output voltages here) but I assume the 1V15 is referring to the Boot CPU rail, typically when this rail fails short in combination with your 1V8PDR, then in most cases it’s the SoC which is dead… even still you can try pulling the output inductor on your boot CPU rail and see if your readings change to narrow this down and then depending on which side of the inductors pad remains shorted pull the Max PMIC… but I expect they’ll stay the same (or further point twards) and the fault will remain with the SoC unfortunately
So my meter is a manual range and is a rebranded (British Telecom) Fluke but hasn’t be calibrated for a couple of years so may not be super reliable. That said i have just checked the 1v15 point again and with the meter set to 200ohm I am still getting a reading of 00.3/4 short to GND.
Please excuse my ignorance, but where would I locate the output inductor and the Max PMIC?
