Latop surface component breaks off

A picture would help. However, from the description (tiny, beige) I'd guess that it is a non-polarized capacitor similar to and you can safely replace it in either orientation. Remove all of the remaining solder from one pad (so that it's smooth) then flux and tack the cap to the opposite pad. When it looks like it's oriented right, tack down the other pad.

Thanks for replying. That's about what I found out and I got the unit back up, albeit without apparent battery functionality, and a slight off color smell. Powered down after a few minutes but on the second boot-up, the box was on breifly and then went blank after a pop. I disassembled back to the MB and the dislodged capacitor I had soldered back on had had some malfunctrion and was no longer soldered on.

I know it's a capacitor per writing on the MB, PC108. It's in a group of 3 and after soldering the pc back and reassembling the laptop, I check omhs across each of the 3 caps and all read about 113-116 on a VOM.

Trying to be brief: it's tight in there particularly since the power jack has been resoldered, but I'm still hopeful about the repair. The unit did function after try 1, so I think that if I can get the cap back in there, there's a good chance of success as caps do fail, people replace them and th eunits function even if there is a pop when they fail?

In the back of my mind, I still wonder about the polarity issue though I can't see how to tell one side from the other. Unless I'm using magnification? Am I correct to be concerned? Have I provide enough info to determine?

From where I am, I need a replacement cap. Can I go to the stockpile of old boards and eyeball a replacement? Or is this the kind of repair that I might be able to get done a shop that might bail my sorry butt out?

Lastly, it's hard to desolder. Do you have a toll recommendation?

I just checked out the link, it is an MLCC. I haven't finished reading yet, Would this component be heat damaged in a bad soldering job?

Thanks for listening.

The easiest way to remove them is either a hot air station or a pair of soldering tweezers, which are like a pair of small soldering irons joined at the hip.

A home-made jig can work pretty well for occasional use. The business end is fashioned from a bit of heavy scrap wire, pounded flat and notched to fit around the dimensions of the surface-mount component that's the target. The other end gets jammed into your soldering iron in place of the regular tip (although not all irons have heaters that facilitate this). Or, use one of the iron's tips and file out an appropriate gap to fit around the capacitor so that both pads are heated simultaneously. This will ruin the tip, of course, so better to either make the sacrificial wire tip or get a cheap iron (with removable tips) and sacrifice it instead of your regular one.

As I understand it, sufficiently severe uneven heating of an MLCC (possibly exacerbated by the mechanical shock that originally struck it from the board) can delaminate it, which might have turned the capacitor into conductor and lead to the dramatic end.

You want to measure the cap BEFORE you solder it back in. Measure the volts across the pads it fell off and put that many volts on the cap for a while and see if it heats up.

It will take half a millisecond for someone to give a hundred examples where the following is not true...but...statistically... removing any one of the caps on the motherboard will likely NOT cause it to fail completely/catastrophically.

Are you absolutely/positively sure you have the right replacement jack. Not all have the same pin connections, even if they fit the holes. I'd check for shorts under the jack and in the vicinity where you soldered. The fact that the AC supply function didn't work is a clue that something is wrong there.

I have no idea your electronics experience level or the equipment you have available. There's a common power supply failure mode. The internal resistance of electrolytic caps starts to increase as you stress/age them. If you start with 20V and switch it down to 3.3V for the processor, the series resistance starts letting those voltage spikes through. Eventually, you have a node that still reads 3.3V on your VOM, but if you put a scope on it, you see 20V spikes with an average voltage of 3.3V. The caps on the 3.3V node don't like the spikes. Nor does the processor that it is driving. It may still work, but have enough internal damage to overheat itself.

This can happen in the external AC supply and/or any of the switchers internal to the laptop.

I've seen open power supply caps take out all the IC's on a monitor board. This is not typically a problem for small caps like you describe.

You can look with a scope if you can put all the heat sinks back on with it disassembled and still get at the part in question.

Are we having fun yet?

There is a good possibility that you can just leave it out. There are lots of those caps all over the place and since this one is near the power jack it most likely only reduces EMI slightly.

Chances are you overheated it reinstalling it. The first thing I would do i s to see if it will fire up without it because there is a good chance somet ing else is fried now.

Hopefully that will just be a fusible link of some type.

Computer equipment generates EMI all over the place. The PS is switched mod e so it generates. There will be regulators on the mobo which are also swit ched mode. Those caps generally smooth out the HF ripple not sufficiently f iltered by the crapola SMD electrolytic nearby. This is not necessary for t he operation of the circuit usually in a case like this. When you see one n ear a big damn chip, that is a different story.

But this is almost assuredly in the primary/power/charging circuit.

If the thing runs without it, consider just leaving it that way. I'd say th e odds of it still meeting FCC and CFR requirements are about 90 %

those caps all over the place and since this one is near the power jack it most likely only reduces EMI slightly.

see if it will fire up without it because there is a good chance someting else is fried now.

it generates. There will be regulators on the mobo which are also switched mode. Those caps generally smooth out the HF ripple not sufficiently filtered by the crapola SMD electrolytic nearby. This is not necessary for the operation of the circuit usually in a case like this. When you see one near a big damn chip, that is a different story.

odds of it still meeting FCC and CFR requirements are about 90 %

Very likely. Also, Muntzing. ;-)

On Sat, 02 Feb 2013 09:14:24 -0500, Rich Webb put finger to keyboard and composed:

odds of it still meeting FCC and CFR requirements are about 90 %

He sounds more like an accountant than an engineer.

- Franc Zabkar

odds of it still meeting FCC and CFR requirements are about 90 %

No, he was a cheapskate. He started the race to the bottom of the barrel in quality consumer electronics. Muntz TVs were a real bitch to service. By the time the crap hit a shop, it had multiple, interactive problems, and the owners were as cheap as Muntz so they wanted them repaired for $2 or less. Very few shops would touch them, away from his retail stores on the US West coast.

Hmmmm, the more things change.........

...the more they end up in China...