Repairing A Damaged RC Rx Due To Reverse Polarity Power Input

Rx Receiver Repair

Once in a while all of us technocenti get a little complacent and do something that may be considered ‘dumb’ while working on a project…. like cutting the wrong side of a piece of wood or welding a bracket on in the wrong direction. [Santhosh] is human like everyone else and plugged in the power connector to his RC Receiver incorrectly, rendering the receiver useless. How will his Arduino-controlled Robot work without a functioning receiver?

[Santhosh] started by opening up the case to expose the circuit board and checking out the components inside. The first component in the power input path was a voltage regulator. Five volts DC was applied to the input side of the 3.3-volt regulator but only 1.21 came out the other end. Now that the problem was quickly identified the next step was to replace the faulty regulator. Purchasing an exact replacement would have been easy but cost both time and money. [Santhosh]’s parts bin contained a similar regulator, a little larger than the original but the pinout was the same.

The regulator was replaced but needed an extra jumper to make up for the form factor size difference. After everything was bundled up, power was applied and it worked. Success!

Rx Receiver Repair





21 thoughts on “Repairing A Damaged RC Rx Due To Reverse Polarity Power Input

  1. you are very lucky it was just the 3.3-volt regulator blown.

    todays electronics dont always tell you when they are blown (no pop or smoke they just dont work).

    for the benefit of those who dont know or are new to the very basics of wiring electronics rc electronics are wired so that the red or + wire is always in the middle inline 3 wires.

    so if you reverse the plug from an esc to the Receiver or the servo to the Receiver the black or minus connects to the signal pin and the signal or white connects to the minus and nothing happens (no destruction or functionality)

    for the average rc user no skill is needed to ensure proper connection of Receivers, escs* and servos without fear of damage as long as you are using the parts for rc use

    *= some soldering may be required to connect battery and motor wires on esc

    most rc escs and servos uses red black and white but some may use different colors so refer to the instruction manual that comes with the parts for wiring colors.

    if you start modifying or using the parts outside of rc such as cutting and soldering the wires or wiring them for other non rc application the great care must be taken not to destroy the part and you also put the warranty at risk too.

    another way you could blow rc parts is exposed pins some cheap servo testers like the ones sold under the nam esky sold on ebay are nothing more than just the board with a plastic or paper wrap for a case with the pins exposed so make sure not to have anything that can short to the pins in the servo tester.

    1. I liked the article. Good photos. Nice introductory subject that will encourage beginners. Saved a little space on the landfill and there’s nothing better to practice on than something inexpensive. Definitely in the hacker spirit.

  2. I thought this was going to be a nice trouble-shooting log. I thought surely the reg wasn’t the only problem, there’s going to be a “but that wasn’t the only problem” after the break.

    As much as I dislike the “not a hack” camp, replacing a voltage regulator is _not_ a hack. It’s a repair, and it’s not remotely interesting.

  3. I found this useful. I just wish it was posted before ending my weekend hackathon about 47 hours early to wait for a new receiver.
    Thanks for the writeup

  4. Yeah, seems like a waste of time.

    A R6B receiver goes for around $12 USD. Santhosh says he “fixed” it for the cost of a part and 15 minutes of his time. There is NO WAY he diagnosed the problem, researched replacement parts, removed the SMD part, made a custom breakout board for the new part, wedged the new part in, reassembled the receiver and tested it in 15 minutes.

    More likely way past a hour (or two) was pissed away “fixing” a $12 piece of equipment.

    1. your right its not a hack. we arent forcing you to read the entire article.
      you should get a refund for your subscription to this site…

      maybe he wanted to do something like fixing something.
      and we wanted to read about it. its better then stareing at the articles we’ve already read today.

      maybe he is one of the MANY people around here that might actually BUY something verified to be broken (for like 1$), just for the FUN time spent fixing it OR to find out what exactly happened.

      then, AFTER fixing it, decide if he wants to scrap it for parts, or just get rid of it.
      also, AFTER fixing it, decide if it’s worth buying a new one of same model…

      after all, a fair share of hacks ending up on this site are the result of being FORCED to open a device upon which one maybe realise possible future hacks…
      if only it is repaired first!

      PS: thanks to this article, we all now know we can substitute that reg. for this reg. …
      WITHOUT having to compare each little detail on the data sheet! it worked :D

  5. Agreed on all fronts. This isn’t a hack. It’s a bodged repair. Yes, it fixed the problem. No, it wasn’t hard. If you haven’t replaced a voltage regulator before, you haven’t worked in electronics. Its a common failure.

    Now, had he put in some reverse protection diodes, I’d call that a basic hack. Its such a cheap addition that many board designers skip to save money.

  6. Seeing his multimeter makes me want to try coloring one of my Harbor Freight give away meters. It looks like a similar meter to me. Much snazzier with the ranges different colors though!

  7. I have a Turnigy RC (TX/RX), the transmiter uses a 8 AA batteries power that I replaced by a 11.1V LiPo battery pack and work well. But one day my son connected the pins in reverse polarity …. and some components blew out (and some smoke came from the receiver). It was the “inaugural” flight that never happen and we were frustated… Since then, the TX is abandoned and waiting to be fixed, if possible. Can it be done? how can I repair it? any advice?

  8. dear sir,

    plsss help me

    i have fly sky fs6 channel transmitter,due to wrong polarity the two capacitors were blasted (47uf 25v) i replaced the same value capacitor but still its not working
    can you plssss suggest any other method for checking
    its a one week old transmitter i haven’t used it also
    i will waiting for your replay

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