Resistor identification

Other Hardware General Electronics
1

I am trying to identify and replace a burnt out resistor:

I think it's the same as its neighbour to the right, a brown black brown gold. The burning makes the rings hard to see. They both give 100 Ohms in situ. The thing is, it's huge - 15.3mm long and 4.3mm in diameter.

Does that make it a 100 Ohm, 5%, 2 Watt? Where is the best place to get such a thing in the UK?

Thanks

2

It looks that way.

3

SpikeUK2564:
The thing is, it's huge - 15.3mm long and 4.3mm in diameter.

Bigger than average, but still pretty small in the scheme of things.

It's probably 2W, available almost anywhere they sell resistors.

I'm not sure the colors are the same though. The middle band looks more grey than black.

4

100 ohm, 2W:
http://uk.farnell.com/jsp/search/browse.jsp?N=215514+731+2031+110030112+110093945&Ntk=gensearch&Ntt=100&Ntx=mode+matchallpartial&No=0&getResults=true&appliedparametrics=true&locale=en_UK&divisionLocale=en_UK&catalogId=&skipManufacturer=false&skipParametricAttributeId=&prevNValues=215514+731+2031&mm=1000635||,1000194||,&filtersHidden=false&appliedHidden=false&autoApply=false&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D215514%2B731%2B2031%26Ntk%3Dgensearch%26Ntt%3D100%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK%26divisionLocale%3Den_UK%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D215514%2B731%2B2031

5

Well, that didn't paste well!
Use their filtering tool. 100 ohm, 2W, many options, example:

6

Do you know why it burnt out?

7

@ CrossRoads - nice find, that looks like the one. Thanks

@ dannable - No, I don't know why it burnt out, but I do know that a new board is £480 + vat, so I'll try replacing the resistor, first.

8

SpikeUK2564:
@ dannable - No, I don't know why it burnt out, but I do know that a new board is £480 + vat, so I'll try replacing the resistor, first.

Order several of them. If it burnt out once it will probably do it again....

9

SpikeUK2564:
@ CrossRoads - nice find, that looks like the one. Thanks

@ dannable - No, I don't know why it burnt out, but I do know that a new board is £480 + vat, so I'll try replacing the resistor, first.

Replacing it first will just most likely result in burning up the next one. A burned up resistor is telling you that too much current flowed/will flow through the resistor. So step one is to determine what is drawing too much current. Is there a short circuit downstream of whatever the resistor is wired to? Resistors don't burn themselves up, they simply obey ohm's law.

Lefty

10

can you find the schematics of the board, if you can, u are able to look up the value by looking for R4 in the schematics.