What Electronic Component Is This?

Thread Starter

Sp@ceR

Joined Mar 11, 2018
29
Hi guys,

I am trying to recap my telephone because of some intermittent hissing noise. Then I came across this component which looked like a shrinked capacitor, but apparently it's not a cap:

Spacer_inductor1 .png

The sleeve don't have any rating. I think the word is brand only. Here's the PCB marking:

phone 2.jpg

Can anyone identify the component and what rating should I get as a replacement?


Thanks in advance :)

Moderators note : removed useless space from picture
 

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MaxHeadRoom

Joined Jul 18, 2013
19,006
It is an inductor (coil).
Often no value printed on them.
Normally show continuity across the pins.
L also indicates this.
Max.
 

Thread Starter

Sp@ceR

Joined Mar 11, 2018
29
Hi Max,

You are right. There's continuity between the pins. Is there any way to look for the replacement without knowing the inductance value?
 

AlbertHall

Joined Jun 4, 2014
8,317
Hi Max,

You are right. There's continuity between the pins. Is there any way to look for the replacement without knowing the inductance value?
Why do you think it's faulty?
If it has continuity then it's probably OK.
 

DickCappels

Joined Aug 21, 2008
5,877
First of all, why do you want to replace it? If it isn't physically broken, then it probably works fine. It is probably some copper wire around a ceramic core -these things don't fail often.

Often there will be a number stamped on the top of the core, and if this one has that number, that's the value.
 

MaxHeadRoom

Joined Jul 18, 2013
19,006
Hi Max,

You are right. There's continuity between the pins. Is there any way to look for the replacement without knowing the inductance value?
As others have mentioned, probably OK if you see continuity, as an aside, for inductors I usually go to CoilCraft, they have sent me a few free samples in the past.
Max.
 

MisterBill2

Joined Jan 23, 2018
3,861
Not only is the device in the pictures an inductor, it is probably a ferrite cored inductor, and unless the material is broken it is OK. If it had suffered an over-current then the heat-shrink would be partly melted. So it is an OK part. If there is an intermittent noise in the phone the fist thing I would check is the microphone conductors in the handset cord, followed by the soldered connections to the modular connectors on the circuit board. That was the problem with one of my phones that became noisy. Resoldering the joints was the solution
 

Thread Starter

Sp@ceR

Joined Mar 11, 2018
29
Thank you all for the replies.

I'm replacing the inductor because one of it has a corroded (rusted) leg, still the continuity tested ok.

@DickCappels I couldn't find any value from the top of the core or bottom of inductor. This is usually how cheap Chinese components are manufactured I guess :D

@MisterBill2 I resoldered the board today with new electrolytic caps (8 in total, replaced 7. I bought one with a wrong value 22uf instead of 2.2uf). Now the noise is not so loud anymore but it's still there and the DC is cut off randomly at the handpiece. I'll have to recheck soldering joints and more deep inspection tomorrow.
 

AlbertHall

Joined Jun 4, 2014
8,317
I'm replacing the inductor because one of it has a corroded (rusted) leg, still the continuity tested ok.
The wire is unlikely to be made of anything that would rust.
The picture below shows some enamelled copper wire which the coil will be wound with. Is what you see just a section which has not had the enamelling removed?
 

Thread Starter

Sp@ceR

Joined Mar 11, 2018
29
The wire is unlikely to be made of anything that would rust.
The picture below shows some enamelled copper wire which the coil will be wound with. Is what you see just a section which has not had the enamelling removed?
Albert, the inductor leads I see are just like the normal transistor/ diode leads. They are not copper as you can see below:

Spacer_inductor2 .png


Ps: I'm not sure it's rust. Like some sort of black stuff on the leads.

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MaxHeadRoom

Joined Jul 18, 2013
19,006
Probabally the 'rusted leg' is the pins just have remnants of flux corrosion etc remaining. ;)
Max.
 

DickCappels

Joined Aug 21, 2008
5,877
You can just (carefully) scrape the leg clean, then thoroughly coat with solder and solder it back in the things are hardy and are not bothered by a little corrosion.

By the way, Sp@ceR, I have hundreds of the very cheapest bobbin inductors (no names on anything) bought in one of the markets in Shenzhen. Absolutely the cheapest parts you can get, and with absolutely the minimum specifications if you can get any at all. These happen to have inductance values stamped on them, but there are probably people out there saying "Trust me, these are 68 uH -here, test one!" There are different ways of doing business the world around.
 
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