MacBook Charger Repair Help

[Phil77]

My MacBook charger stopped charging when plugged in. I opened the charger and instantly saw the issue. I'm not sure if the part is a ceramic disk capacitor or not. It looks like one. The part is definitely burnt though.

I desoldered the piece and removed it from the circuit board to see if the information was legible. It isn't. What I can make out on the top line is NTC. I can only see part of the first number on the second line. It looks like a 2. I don't know if it is pertinent or not but, the ceramic coating is colored black.

On the circuit board itself where the disk capacitor is/was reads "RTH."

If anybody knows what this part may be, I would greatly appreciate any insight.

In advance, thank you.

 

[alec_t]

Could be an NTC thermistor. But then again......
Try thermistor suppliers' web-sites. You might spot an image which resembles your component.

 

[Phil77]

Somebody in a different forum said I should post a picture. I don't have a camera and the camera on my phone sucks. I'll go ahead and post it here anyways.

Another point this person brought up was whether or not I could clean up where the writing was. Unfortunately, no. It isn't burnt with charcoal, the short actually blew some of the ceramic coating to dust. You should be able to tell that from the picture. Also, the connectors (legs) were so brittle from being burnt that they just crumbled off when I desoldered them.

@Alec - Yea I was thinking that too. I did do a web search for NTC and that's what came up. I was wondering, how could I find out or figure out the specific type? Does the writing on the circuit board indicate anything?

Thanks again.

**broken link removed**

 

[bountyhunter]

NTC probably stands for "Negative Temperature Coefficient". That could be a surge limiter whose resistance is high when cold, but drops as current flows through it. It also tends to act like a fuse which means any significant circuit failure in the device could have burned it out.

On the circuit board itself where the disk capacitor is/was reads "RTH."

That could be "Resistor Thermal"

 

[KeepItSimpleStupid]

Likely an inrush current limiter: http://search.digikey.com/us/en/cat...-limiters-icl/656273?k=inrush current limiter Usually you can select one based on the steady state current. However, we don't know where it is in the circuit and therefore the current.

It can and does act as a crude fuse, so there may be more issues.

NTC - Negative Temperature Coefficient (Resistance goes down with temperature)
RTH - Reisistance (Thermal)

 

[jimy245]

please search out this with power supply model number on web....or post here i will search it.thanks

 

[Phil77]

please search out this with power supply model number on web....or post here i will search it.thanks

I did search the model number but couldn't find any useful information on it. Here it is in case you have better resources.

Model number A1184
60W
Input: AC 100-240~1.5A 50-60Hz
Output: 16.5V(solid line above dotted line)3.65A

Thanks to everybody who replied. However, I'm such an amateur that it doesn't really help.

 

[bountyhunter]

Thanks to everybody who replied. However, I'm such an amateur that it doesn't really help.

Don't feel bad. I spent 30 years designing switching power supplies and even my chances of fixing it would be slim. When off line switchers blow, they usually take out a ton of circuitry. You are left trying to find parts that are typically proprietary ASICs made just for that device and not documented anywhere. And even if you could find all the parts, the cost would be about 10X what the unit costs. That's why blown up units end up in landfills.