How do i identify a burnt resistor on a circuit board ?

Question

tcu in a honda accord and it has 2 resistors burnt black, how do i find out what kind they are ?

Answer 1

normally you read the code [the series of color banding around the resistor], if it is burnt you might find it on the underside. don't know the code but it is on-line somewhere.

if you cannot read it you'll need the schematic that has the values. hopefully someone has a link to that. you might want to post more info about the board [maybe the ID number] and its use.

good luck

Answer 2

As some have noted, it used to be possible to sort the color code on resistors that weren't too badly burned. However, after getting that hot, it is often difficult to tell red from orange, for example, which could easily throw off your values by 10X, or yellow from brown which could throw you off by 1,000X!

These days, resistors are surface mount, and have no colored bands. If you're very lucky, you can read the silkscreened value on the larger ones after they're toasted, but not readily.

After toasting, whether you've got the axial lead style or surface mount, the odds of being able to get a reading that's within a mile of the original value (after isolation from the board) are about nil.

It's unlikely that you'll find a schematic for the board...

But all is not lost! See if you can have a look at an *untoasted* board in a junkyard or auto parts shop. I can't tell you how many times being able to look at a functional (or at least not smoked!) board has saved my butt in similar situations. If colored bands on a axial part or clear silkscreened markings on a surface mount part exist, anyone familiar with electronics can get you the right part.

Of course, that's only step 1. You really DO want to know what took them out in the first place!

Answer 3

Try to find a good version of your board at a junk yard or get an owners manual with schematics. Otherwise you'll have to guess by figuring what the circuit is doing and applying a decent equivelant, depending on how crucial the value is.

Answer 4

it will be darkened a little, but the best thing to look for is right where the resistor is soldered to the circuit board if it is bad it will look black to dark brown as opposed to a good one that will look silver and metallic.

Answer 5

They are color coded and the color code refers to resistance .If it is burned black you cannot tell . you will need to go to honda .

Answer 6

Gimme until tomorrow... I have the answer for you at work.