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This is from a surgical operating table. I believe this resistor is bad. Im not 100% sure. I test it and it gives me no reading at all, no resistance reading nor contuinity reading.

enter image description here

Edit* Added a picture of the underside.

enter image description here

ItsMitch
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    Looks like some power resistor. The fact it is required to be raised is probably due to it is getting very hot. But I don't think the value can be determined from this image. – Eugene Sh. Nov 27 '17 at 19:58
  • How can I find its value? I have no service manual, nor schematics. – ItsMitch Nov 27 '17 at 19:59
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    @ItsMitch Find a good unit and test the part in it? There don't appear to be any markings on that part, so there's no way of telling what the correct value is. –  Nov 27 '17 at 20:00
  • This is the only unit in our lab right now. – ItsMitch Nov 27 '17 at 20:01
  • Is there any markings on the bottom of it maybe? Can you tell what is it's function? – Eugene Sh. Nov 27 '17 at 20:02
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    Welcome to EE.SE! This appears to be a repair question. Please be aware that questions on the reverse engineering, modification and/or repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired, so that you can ask specific, focused questions that can be answered concisely. More information can be found [here](http://meta.electronics.stackexchange.com/q/2478/11683). – Dave Tweed Nov 27 '17 at 20:07
  • Added a picture of the underside. One leg is connected to power input, the other leg is connected to a relay – ItsMitch Nov 27 '17 at 20:18
  • Can you tell what kind of relay is that (and which relay pin it is connected to) and what power input is there? – Eugene Sh. Nov 27 '17 at 20:19
  • Single Pole Double Throw 12V – ItsMitch Nov 27 '17 at 20:21
  • sorry its actually 26V – ItsMitch Nov 27 '17 at 20:27
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    No way to tell by looking at it. If you could trace out the entire circuit (including the load on the relay) you might be able to reverse engineer it. As @DaveTweed says, you'll need to do a fair bit more homework to get the necessary info. – Heath Raftery Nov 27 '17 at 20:30
  • related: https://electronics.stackexchange.com/questions/296421/resistor-with-only-2-color-bands – John La Rooy Nov 27 '17 at 20:36
  • @JohnLaRooy How did you even find that one? :) – Eugene Sh. Nov 27 '17 at 20:40
  • Also this one: looks like the bands can fade away on those resistors :( https://electronics.stackexchange.com/questions/246322/4-5-band-5-resistor-with-superfluous-black-end – John La Rooy Nov 27 '17 at 20:43
  • @EugeneSh. google image search – John La Rooy Nov 27 '17 at 20:45
  • You can see the ghost of one of the faded bands in the second picture. – John La Rooy Nov 28 '17 at 22:04

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To sum up:

  1. It's a power resistor. If you measure the body size and length you could likely find out what wattage it was.

  2. It has a color band, and likely had more before the heat burned them away.

  3. You are unlikely to ever measure continuity through a resistor. It's the opposite of what a continuity test measures. The open circuit and no resistance tells you that it's damaged though.

  4. Find out what it connects to and what voltage may be across it would go a long way into guesstimating the resistance and confirming the wattage.

Since you said 26V power input, and as a resistor on the coil for the relay, the real question is what is the model of the relay. This will tell you the intended coil voltage and amperage, which you can then use to figure out the resistor value. It's basically a voltage divider. Or if it's on the switched pins of the relay, trace it out.

The other options are to contact the manufacturer, Google search for pictures of the circuit board hopefully with the resistor color bands in view, or ask someone to take pictures or measure the resistor in a good model.

Passerby
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