T43p AC adapter / battery 'problem'

[Alejandro Audisio]

My T43p is acting strangely with my AC adapters. Ive just noticed that the battery LED indicador on the laptop does not stay calm, instead it insists on turning itself on and off constantly. What worries me the most is that as the LED turns on and off, there is a spark like noise, its not a loud spark, but something like a mild clicking noise.... its not the hard drive BTW, as this happens when I only have in plugged in and the system is not turned on. Then this morning I could swear it made a louder, crisp and clear poping sound... like the sound youhear when you burst a a bubble on some bubble wrap paper.... and I thought I sensed the smell of a little plastic heating up.... all with the laptop operating normally, at least nothing apparent is wrong. Ive of course unplugged the AC adapter and all still works OK... the green battery LED does not blink anymore (when I dont plug in the AC adapter).

BTW, I have 2 AC adapters and the LED blinking and little sparky noise happens with both AC adapters... hence my focus is on the laptop.

Any ideas on what is going on..??? Im scared to death to charge the laptop... do I have a short circuit somewhere..???

Thanks,
Alex

[sjthinkpader]

Seems some high current path has a solder joint crack. Inspect the large inductors to see if you can find the crack.

[Alejandro Audisio]

Seems some high current path has a solder joint crack. Inspect the large inductors to see if you can find the crack.

Sorry... non EE here... could you please translate this to layman terminology...??? Many thanks.

[Alejandro Audisio]

Bumping this up.... still dont understand what an inductor is.

Also, the laptop works fine if I use the AC adapters with no battery installed..... does this help in the diagnosis...???

Thanks,
Alejandro

[rkawakami]

Here's a picture of some inductors off a T23 motherboard:

http://www.kawakami-ca.com/ibm_t2x/t23_inductors.jpg

There are probably similar looking ones in the T43p. I believe what sjthinkpader is saying is that since the inductor usually handles some high currents - can be a few amps - that if there is one which has developed a crack in the solder joint, then the popping or cracking noise you hear is being caused by a spark of electricity. The solder crack could mean that the inductor is not completely bonded to the motherboard and therefore, it's partially disconnected from the circuit at times. Every so often, with movement of the system or simple thermal expansion, the contact between the inductor's terminal and the motherboard gets a little worse and you get a spark.

Since you have discovered that the system works fine both when using only the AC adapter or only on battery power, then the problem could be in the battery charging circuits on the motherboard. Of course there could be a problem with some other parts in the system but looking for a loose inductor may be the easiest thing to do; well, you probably have to strip the motherboard out but you won't need any fancy electrical test equipment. When you have identified such an inductor, try lifting one corner with a toothpick and see if it gives. If you do find a loose one, then the fix is to re-solder it back onto the board. Make sure that the contacts are clean and shiny (scrape any black or grey oxidation off) before attempting to solder it.