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Help! My iBook Burst into flames!

A

appleguru

Senior member
Ok, so maybe I was asking for it by running the iBook (2001, 500Mhz (Though accidentilly underclocked to 400MHz.. don't ask 😛), "dual usb" model) without its case, bare, on my desk for over a year.. but in any case, a high pitch noise emereged, and continued to grow.. until *pop* a FLAME burst out of the bottom of my iBook, accompanied by a puff of smoke.

After some close inspection, it appears the chip "Q72" on the bottom of the motherboard has exploaded. It's right near where the white sleep LED on the front of the iBook plugs into the board.

If anyone has any info on this part (a part number would be awesome.. I'd get it myself if I could read the chip.. but all markings have been burned off :/), I'd be more than appreciative... Here's to hopes of getting my baby back up and running.
 
That one chip is NOT going to be the only damage I can assure you. The mobo's probably a goner.

Laptops don't just burst into flame for no reason. You either had a short circuit or over-voltaged it.

Were you using a stock power supply? Perhaps you shorted one of the USB ports?

 
No, I'm 90% sure it's just that chip. It was more like a fireball, didn't actually burst into flames.. I watched it happen 🙂 In any case, replacing the chip is certainly worth a shot...

As for why it happened.. yes, it's the stock PSU, but the DC board on the iBook has long been fried (IE burnt black for several years). It has, however, run fine since then, with the exception that the battery never really charges...

It's quite possible something shorted.. Again, it was sitting on my desk BARE. IE, the motherboard was exposed to the surface of my desk (I know, I know.. don't even go there 😛). But I'm farily confident that replacing the one blown up chip will enable it to at least work again (for at least a few months.. which is all I really need out of it 🙂)
 
Q usually means a transistor - most likely it's part of one of the voltage regulators which you burned by shorting it out.

A faulty voltage regulator might also make funny squealing noises as it dies.

The problem is that a dieing regulator can produce all manner of power spikes, which can trash the delicate components the regulator is designed to protect. Additionally, a short circuit can easily burn through some delicate traces on the motherboard (in modern motherboards, these traces may well be 'buried' inside the structure of the motherboard, and therefore not be visible). Or indeed, if a component actually burns, it can damage nearby traces through heat alone.

It might be fixable, but TBH it's almost certainly dead - and besides you don't actually know what caused the fault. If the original problem still exists, the same thing will happen to your newly repaired board.

Cliff's notes:
It's probably dead.
 
🙂 I still think it's worth a shot at repair 😀

In any case, I know it's likely a multi-layer pcb.. but the external traces and co,ponents near it all look just fine. The "explosion" was over with pretty quick and I doubt the heat caused any damage (it was less heat than a soldering iron produces (as it was more spread out), and it was much quicker... That's not to say a voltage spike/etc didn't kill any other components, but I'm fairly cnfident taht replacing the part would fix it 🙂

The chip is an 8 lead SOIC SMT chip.. There's one, marked "Q73" somewhat close to it.. That chip may or may not be the same, but is marked "4410 Y006A"
 
It's probably an FDS4410 N-channel MOSFET. This is an obsolete part and is no longer available.

However, you could probably get by with the nearest equivalent which is a STS11NF30L
 
If anything drew enough current to BURN then you've almost certainly got other damage: melted foil traces, other parts damaged. You could have damaged traces in an inside layer and never know. Not to mention that if anything in a PC burns it's certainly due to a short circuit. You replace that chip and it'll probably burn again unless you figure out what's shorted out.

I'd look into replacing the whole mobo. You might find one on Ebay.

 
Thanks for the info Mark... I'll order that part and see if it does the trick.

FlyingPenguin... While you're probablly right, I still think it's worth a shot.. and as for replacment mobo from ebay.. I'll have a look 🙂 Thanks guys!
 
BTW, Mark R.. you think the FDS4410A would be an adequet replacement for the FDS4410? Or do you think the STS11NF30L would be better?
 
Yeah, the FDs4410A is virtually equivalent - wonder why I didn't find it before. The STS11NF30L is actually a slight upgrade.

Just had a thought - for one reason or another, manufacturers sometimes use 2 different transistors on a regulator. Let's just hope that this isn't the case with your board.

 
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