Toshiba Laptop Power Supply: Replacing inductor in the EMI filtering section.

[JonathanAnon]

Hi friends,

I'm fixing a Toshiba laptop charger and it seems that while opening the case, I cut the wire on the inductor in the EMI Filtering section. So there is now an open circuit in the primary side between the fuse and the bridge rectifier.

I've pulled open a few other toshiba supplies that I keep spare, but I cant find one exactly the same. I found one that was similar, but the core that the wire is wrapped around is about twice the diameter. (See the attached image).

I've already replaced it, while I had the soldering iron turned on, so I'm just wondering if there is any reason why I shouldnt turn it on and test. I think that the inductor is used as just a low pass filter as part of the noise filtering, and not used as part of power factor correction. What do you think, am I good to go... ?

[paulstef]

Re: Toshiba Laptop Power Supply: Replacing inductor in the EMI filtering section.

I'd say you are good to go. I assume the new inductor has about the same number of turns and are they wound in the same direction as the other one was, right.

[JonathanAnon]

Re: Toshiba Laptop Power Supply: Replacing inductor in the EMI filtering section.

Hey Paul,

it's approx the same amount of turns... I was thinking of maybe taking the wire from the replacement inductor to rewind the original with the same number of turns... but tbh, for a laptop adapter it's not really worth the time...

I'm not sure whether I put it in wound in the same direction.. forgot to take note of that :-(.... Why would that matter given that it's A/C at that point in the circuit?

[paulstef]

Re: Toshiba Laptop Power Supply: Replacing inductor in the EMI filtering section.

Hey Paul,

it's approx the same amount of turns... I was thinking of maybe taking the wire from the replacement inductor to rewind the original with the same number of turns... but tbh, for a laptop adapter it's not really worth the time...

I'm not sure whether I put it in wound in the same direction.. forgot to take note of that :-(.... Why would that matter given that it's A/C at that point in the circuit?

Well I don't think it matters. It's just that the original windings are probably in the same direction (common mode) and I don't know where you took the replacement from.

[JonathanAnon]

Re: Toshiba Laptop Power Supply: Replacing inductor in the EMI filtering section.

Well I don't think it matters. It's just that the original windings are probably in the same direction (common mode) and I don't know where you took the replacement from.

It's another inductor from the exact same position (between fuse and BR) of a very similar toshiba laptop power supply, so I'm confident it's a good fit. I'll just check that it conducts along the same paths as the old one....

Then batten down the hatches and plug it in .. :-)