# Electrical fuses

## Determining if a fuse is blown

It is easily determined if a fuse is blown by using a multimeter to measure if the fuse is still conducting. If you are certain that a fuse is blown, you will have to replace it by a similar fuse that can handle 500 mA.

{% hint style="success" %}
The fuses have **changed on recent boards** to an **automatically resetting type**. You should **never have to change them**. If they do open, simply **wait** a very brief amount of time for them to reset. However you should determine \*WHY\* the fuse opened before attempting to use the board. 
{% endhint %}

## Fuse locations

RDDRONE-FMUK66 has three fuses, two (F1 & F2) for the CAN transceivers, and one (F3) for the USB port.

![Locations of the fuses on the Rev. B board. All three fuses are located on the back of the board.](/files/-LOrxKMzoFtbF3Enc0oq)

## Fuses F1 & F2 (CAN transceiver)

![](/files/-LOrw_zgqTQ21VtbKFSw)

## Fuse F3 (USB port)

![](/files/-LOrwcXUTl4SuJWwCxGo)

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