What kind of resistor is this?

Thread Starter

pand0ra

Joined Oct 17, 2011
11
I'm trying to swap out resistors and am not entirely sure if it is a 0.2 Ohm resistor and need someone to verify for me (I think it's Red, Black, Silver, gold). Also, where is a good place to pick up a replacement? Digikey?
 

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Wendy

Joined Mar 24, 2008
22,145
You could ohm them with a meter. While they could be burned out, I doubt they are. They are indeed well baked, but a lot of resistors that get hot look like that over time.

I am betting they are 10Ω. From their size I'm thinking either ½W or 1W, and gold is 5% tolerance.
 

SgtWookie

Joined Jul 17, 2007
22,210
I can't really tell.
Red-blk-silver-gold would be 0.2.
Brn-blk-silver-gold would be 0.1.
Brn-blk-blk-gold would be 10, but that 3rd band really doesn't look the same as the black band - to me, anyway.
 

Thread Starter

pand0ra

Joined Oct 17, 2011
11
I've tried a meter (not sure if I'm using it correctly) but it returns nothing. I can get a value from other resistors though.
 

SgtWookie

Joined Jul 17, 2007
22,210
OK, so what is the voltage across the resistors when the circuit is powered?
That will help to decide what resistance should be there.

Looking again at the picture; it could very well be two black bands, as it looks like the center of the resistor (where the gray-looking band is) got a lot hotter than where the definitely-black band is.
 

BMorse

Joined Sep 26, 2009
2,675
looks like Red, Black, Brown to me with a gold band, 1/2 watt
Digikey would be one good source.....

Is that part of a telephone circuit??
 

Wendy

Joined Mar 24, 2008
22,145
That looks like <brown> <black> < maybe black> space <gold> to me, just like the quarter watt off to the side looks <brown> <black> <green> <gold>.

With an ohm meter and no power to the circuit you should get some reading.
 

SgtWookie

Joined Jul 17, 2007
22,210
Our OP has already said that they can measure other resistors, but they get no reading across those two (I'm assuming they read infinite Ohms instead of 0 Ohms)
 

Wendy

Joined Mar 24, 2008
22,145
Perhaps, but it is rare condition. Most times I've ever seen open I've also seen a crack in the resistor. Those look intact. I've had them drift to ridiculous values, but rarely open all the way without physical damage.

I suspect the OP is going to need a schematic or another similar unit. If the similar unit is of the same age I would also bet the resistors look the same.
 

Thread Starter

pand0ra

Joined Oct 17, 2011
11
Perhaps, but it is rare condition. Most times I've ever seen open I've also seen a crack in the resistor. Those look intact. I've had them drift to ridiculous values, but rarely open all the way without physical damage.

I suspect the OP is going to need a schematic or another similar unit. If the similar unit is of the same age I would also bet the resistors look the same.
They look a little burnt in the middle to me so that's why I was guessing they are damaged.
 

Wendy

Joined Mar 24, 2008
22,145
I've seen that look in perfectly OK resistors. I didn't like it, but that is why you need to be sure they are ohmed out. If you have ohmed them correctly and they are open, then that is your problem. However, it is rare, which is why I suggest you do it again to verify they are open. Assumptions are a major pain, and can come back to bite you.
 

Thread Starter

pand0ra

Joined Oct 17, 2011
11
I've seen that look in perfectly OK resistors. I didn't like it, but that is why you need to be sure they are ohmed out. If you have ohmed them correctly and they are open, then that is your problem. However, it is rare, which is why I suggest you do it again to verify they are open. Assumptions are a major pain, and can come back to bite you.
Will do. I'll take another test of them when I get home tonight. Thanks for the feedback everyone!
 

Thread Starter

pand0ra

Joined Oct 17, 2011
11
So, if I set the multimeter to 2kΩ the result I get is ~.491 for both. I think I had it set to volts the first time but didn't notice.
 

Adjuster

Joined Dec 26, 2010
2,148
0.491 on 2kΩ f.s. =491Ω? Identical results to 3 figures from a pair of visibly cooked resistors sounds a bit odd.

Perhaps they are a couple of 1kΩ in parallel, in which case they would be close to nominal values, despite a red band baking to grey.

Of course, it may just be coincidence, really they may be open and other parts may determine the reading.
 

Thread Starter

pand0ra

Joined Oct 17, 2011
11
I'm still learning about this stuff, so should I swap those out? Should they work since they aren't registering at .2 ohms?
 
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