I recently had a bad crash and the 3.3V voltage regulator on the Oilpan that is located close to the I2C port was damaged. I replaced it with an absolutely identical chip (got the correct part number from the DIYDrones store). Now I have a couple of questions:
- the voltage regulator has 5 legs, but judging from the IMU's board layout, only three legs are actually connected to any solder leads. What about the other two? Just not even bother attaching them? I'm asking because the solder pads are missing from those positions on the board.
- measuring the output of the 3.3V regulator with a multimeter, I consistently get 3.45V output. Input supplied to it is about 4.65V. That 3.45V is a little higher than the desired 3.3V. Could this slightly higher voltage cause any problems?
Actually, I just looked at the regulator's output on the oscilloscope. It's a sawtoot curve that has its lower value at 3.3V and a peak-peak measurement of 300mV. So what the multimeter measured makes sense.
I checked a good (uncrashed) IMU today and the ripple on the 3.3V regulator output should not be there. Now I'm wondering if other components on the board are also damaged, possibly one of the capacitors in the vicinity of the voltage regulator.
Any help is greatly appreciated! Thanks, Jan
I managed to clear up this mistery. I had a bad solder connection to ground on the 3.3V regulator chip and that was what caused the behavior described above. I resoldered it and now the output is a steady 3.3V like it should be!
how do you test the voltage regulator? which legs should read what? thanks!