Blogs

No solder method for defective 3.3V regulator for APM

Posted by Franklin Neo on February 27, 2014 at 9:30pm

Discovered a method to provide an alternative 3.3V for powering the onboard Baro, Accelerometer, Compass when the built in 3.3V regulator TPS79133 fails.

I documented the details and equipment required here

http://flight.farbird.com/2014/02/repair-blown-33v-regulator-on-ardupilot.html

No solder method to provide alternative 3.3V source to the onboard sensors.

33v, accelerometer, baro, compass, ins, mpu6000, regulator

E-mail me when people leave their comments –

You need to be a member of diydrones to add comments!

Join diydrones

Comments

Timothy Cipullo June 16, 2014 at 8:51am

Great solution. It worked like a charm and got my APM flying again. No more worrying about blowing another regulator. Thanks for sharing this.
Jorge Brites May 25, 2014 at 12:43pm

I use a Arduino Micro, powered in "voltage in" with 5v UBEC and feed the APM directly with 3.3v.
Don LeRoi March 3, 2014 at 12:42pm

Is the actual board a 3DR?
Franklin Neo March 2, 2014 at 5:54pm

The board pic was a screen cap that was grabbed off the net..
Don LeRoi March 1, 2014 at 7:25pm

@Swift - Fair enough. Thanks for pointing it out.
Quadzimodo February 28, 2014 at 3:34pm

Nice simple solution! Great for fast repair should the reg give up in the field, and just as easily reversed when you get back to base.

I have been extremely impressed with the performance of this particular 3.3V BEC (directly powering the TX in this AV link). NOTE: I am assuming that there is no reason why the 3.3V rail wouldn't be equally happy powered by a switchmode regulated supply as it would a linear one, so if this could be confirmed by a bigger brain that would be tops!
Developer

Bill Bonney February 28, 2014 at 9:43am

The only issue I would be concerned about here is where to source that extra 3v3 and when you do, it needs to be a regulator that can handle the extra demands ie. current draw on it. Otherwise it will be a cascading number of 3v3 regulators failing
Liam Lambkin February 28, 2014 at 4:50am

I have replaced the regulator a couple of times on my APM2.5.2 board. It seems to happen after disconnecting the APM whilst still connected and while powered by external battery.

Since I have been disconnecting from mission planner first, I havent had any issues.
Don LeRoi February 28, 2014 at 4:45am

If this is a common problem, why can't you return it to 3dr?
R. D. Starwalt February 28, 2014 at 4:31am

+1 with John's warning.

The space is probably too small to use a Dremel cutting wheel.

More likely you could use a heavier hobby knife blade and shear the device leads off at the case -- it might take several chops to get a lead cut clean.

Once sheared off, the (presumed) dead chip body can be removed.

Overall, it is a valid method of salvaging or repairing an APM with a faulty 3.3 V reg.

-=Doug