# can i find the resistance of a resistor if its burnt?

in one of my helicopter controllers, there is a burnt resistor. it burned when my brother tried to charge his more expensive helicopter with it.
i looked at it and all i know is that theres a yellow stripe and a gold one, but thats all thats visible since the middle two stripes have been burnt off.

will it still have the same original resistance when tested with a multimeter?
how can i find the resistance of it so i can replace it?
i havent got another one of these controllers to compare it with.
it has a very similar controller shape as the air hogs havoc helicopter, except this helicopter cost only \$20.

because the resistor is burnt out the controller cant charge the helicopter, and i dont know the voltage that the copter takes in, and the copter doesnt have any battery protection circuits as far as i know, so i cant charge it.

can someone help me figure this out?

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framistan5 years ago
If you know how many MILLIAMPERES of charging current is normally delivered to the batteries, you may be able to place a resistor in the spot and see how many milliamperes of current flow (connect a meter to measure milliamps). If the value is too low like one milliampere... then LOWER the value of the resistor and measure amps again. Keep doing this untill you get a charging current that you think is normal or that matches other similar devices. Also you could just monitor the voltage across that resistor, and do a calculation of milliamperes and then convert to watts... (watts equals volts across the resistor times the amperes flowing through it.) If the resistor is a 1/2 watt resistor, then your calculations must be LESS than 1/2 watt or the resistor will overheat and burn out again. Using this kind of deductive reasoning, you could get very close to the proper value, and very likely get the device working again.
Quercus austrina5 years ago
Yellow indicates a 4 for the first digit.  Take a reading with an ohm meter and see if it reads around 4 something. You may be lucky and get the value. If not, try searching for the board number to see if there is a schematic out there.

BTW, here's a resistor color table to use.

Qa
zack247 (author)  Quercus austrina5 years ago
no luck finding a schematic :/
its a generic brand board so im out of luck on that part.

i looked again and the band is orange, not yellow. so it indicates 3.
zack247 (author) 5 years ago
i unsoldered the resistor and no luck, its been burned all the way around.
i looked at the resistor again and it looks like its a orange line, so it indicates 3 instead of 4.

it is a cheap \$20 heli, i got it from a "bargain shop" when i was on a trip in humboldt.
it has a controller design just like the air hogs havoc heli, without the stickers. the second related 'ible has a controller pictured just like mine.
a example of the air hogs controller can be seen in my "nitro mini rc car" instructable.
The nerdling5 years ago
check the coloured bands on it
zack247 (author)  The nerdling5 years ago
two of them have burnt off of the resistor with the coating on it, they might still be there but if they are they are incredibly hard to read..