Repair information for network equipment including routers, modems, and shared storage.

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Need help identifying component

I can’t find what kind of component the black one with 150 on it is.

I thought a condensator but i can’t find anything resembling.

Block Image

Part of a Netgear prosafe m4100-50g-poe+ network switch.

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Hi @gmantunt

Normally there are some tell tale sign at the pcb components, e.g. C = Capacitor,

the picture, i would say is an inductor. It should be Label as L xx on the PCB

The number 150 indicates the value 15uH if im not wrong,

and btw what is the issues with this POE switch?


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Thank you. It is indeed.

For reference to others in search:

After searching a bit on 'Inductor' and 'inductor coil' i found multiple 'ferrite inductor coil' pictures that look the same.

The PCB says L62 and L63 but i don't know what i can do with that.

The switch doesn't have much problems. One fan is broken but still spinning. It was grinding itself away as far as i can see and the switch is filled with nasty dust and plastic. So my goal is to clean it and replace the fans.

While taking it apart i found some spots with an oily substance so i started looking for broken conductors or something similar i.e. the source.

I saw the inductor and was unfamiliair with it. It was weirdly shaped and others looked better so this was a potential broken part.


btw inductors rarely fails..... main concerns are those electrolytic capacitors, esp can be found on power supply....



It looks like a 150ohm inductor coil to me, or it may be 15uH like @salmonjapan said. Take it off of the board and check it with an ohm meter, and see for sure.


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@nick ,

To my knowledge inductors are never marked as Ohms value as their reactance (AC resistance i.e. XL =2πfL) can change with frequency.

Their DC resistance will also be extremely low for that value of inductance as can be seen on this datasheet example for a 15uH inductor. It is in milliOhms

To measure its inductance you would need an LCR meter unless it tested open circuit with an Ohmmeter



@jayeff yea right bro..... having a simple LCR meter is good though......

like for me ... have one cheap gm328a standby ...

inductance measure in henrys


@salmonjapan I've done ohms checks with my multimeter, but I consider it a rough guestimate to be double checked.



I built one from a kit about 20+ years ago but have noticed that there are more up to date ones available now

This (see item #6) or even this but I have little need these days to use one.



@jayeff DMM is def a in a pinch option. Do not rely on it for dead on accuracy.




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