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I'm troubleshooting a control board that has a very long replacement lead time (about half a year) and I think I've identified the faulty component. It is – I believe – a surface mount resettable fuse. It's reading about 45Ω, where all of the other identical components on the board read about 2Ω.

However, the only labeling on it is N⩙ (or maybe ⩙N, that label is symmetric), and I'm having a bit of a hard time finding anything exactly like it online. I've never seen the ⩙ marking before and I don't know what it means in this context, so I don't know what to google to find a replacement.

Any help on identifying the component and/or an explanation of what that label means would be appreciated!

Edit: As requested I've added a photo of the relevant section of board below. I've circled the component in question (on mobile, apologies for the poor circle). This section of circuitry is related to powering a set of six relays, although I'm no electrical engineer so that's all I can really say about it.

Relevant section of board

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    \$\begingroup\$ A picture would be helpful. \$\endgroup\$
    – Chris
    Commented Jul 26, 2022 at 22:32
  • \$\begingroup\$ @Chris Of course, I should have thought of that! I've added a photo. Unfortunately my phone camera struggles if I try to shoot the component too up-close, hopefully that image is clear enough to be useful! \$\endgroup\$ Commented Jul 26, 2022 at 22:53
  • \$\begingroup\$ Looks perfectly clear to me. If you can't identify the component, you might try removing one of the other ones and testing it to deduce its properties. From the looks of it, they are probably identical. \$\endgroup\$
    – Chris
    Commented Jul 27, 2022 at 0:05

2 Answers 2

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Looks a lot like a Littelfuse nanoSMD PolySwitch. Specifically the model nanoSMDC016F, based on this datasheet.

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  • \$\begingroup\$ This really looks right to me, everything that I'm set up to measure matches what I'm seeing for that part on the datasheet! I'm going to go ahead and accept this answer, hopefully we can find a way to order less than a roll of 3000! \$\endgroup\$ Commented Jul 27, 2022 at 14:45
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    \$\begingroup\$ Mouser will sell you a cut tape: mouser.com/ProductDetail/Littelfuse/NANOSMDC016F-2. The picture doesn't match but the product number does (the "-2" part refers to the packaging) and so do the specs. \$\endgroup\$
    – Chris
    Commented Jul 27, 2022 at 19:45
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Depending on the component manufacturer, this could be any value from 100mA to 5A (or more). My SMD fuses marked with N and that sign are rated at 2.0 Amperes. Yours might be different. Try searching the device brand/model, repair forums, or much better, if available, maintenance/repair manual.

BTW it most probably is a resettable fuse. (PPTC)

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  • \$\begingroup\$ It's good advice! I actually have a maintenance manual, but they want you to just replace the whole board if something goes wrong, so it's got no details on the electronics. It's also kind of an obscure bit of equipment – and a beta version at that – so I'm not too hopeful of finding much on repair forums, but I'll look. Thank you! \$\endgroup\$ Commented Jul 27, 2022 at 14:35

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