Laptop doesn't "see" Power Supply

[Piyono]

Hey, guys,

I'm here in sunny Jerusaelm, where I've been using a frined's laptop. Recently the power supply mysteriously stopped working. We chalked it up to an intermittent connection somewhere, because jiggling the plug inside the jack restored power. But that stopped working last night -- no amount of jiggling can resotre power to the machine.
I tested the power supply with a multimeter to make sure it was putting out the requisite 15VDC. It is. I tested the cable to make sure there wasn't a break in it somewhere. Threre isn't.
Seemed logical that the jack had lifted from the PCB and would have to be resoldered, so I disassembled the laptop (*not* fun) and removed the motherboard only to find that the jack was not broken in any way. In fact it is seated quite firmly in its place. I tested for continuity from the jack contacts to the PCB and along the exposed power traces on the PCB and everything seems to be working. No intermittent contacts.

I'm stumped.
Help?


Piyono

 

[Howell]

It could be heat related. Heat can cause a cracked solder joint to expand and lose contact.

 

[Fushigi]

Make sure the pins in the male side of the connector haven't been pushed back too far to make solid contact. We used to see that all the time on serial cables and later on some VGA cables. Haven't seen it on a laptop power adapter but I'm sure it's a possibility. I usually use needle-nose pliers and give the pins a decent tug.

Also, if you've access to another power adapter (or another laptop that uses a similar power adapter) you could use that to isolate between the power adapter & the laptop. I hate to suggest it, but you can buy a spare power adapter and use that for testing/problem determination.

 

[jtr1962]

The steps you took to determine the cause of the problem were exactly what I would have done. While the laptop was open I would have resoldered the power plug connections just in case it was a solder joint problem. By resolder I basically mean just apply a hot soldering iron to the joint and maybe a tiny bit a fresh solder(to get some flux so the solder flows). Keep the joint molten for a few seconds, then remove heat. It goes without saying but make sure the machine is off when doing this or .... :cursin:

Your problem might be heat related, but not due to expansion/contraction. Rather, the power supply may have a marginal component in it that works just fine at cooler temperatures but fails under load at the warmer temperatures in sunny Jerusalem. :sunny:

One more thing-the contacts may just be corroded/dirty. This can occur from humidity or from repeated insertions(no sexual connotations here ). When the plug is inserted there is a spark as the power supply current spikes to charge up the filter capacitors on the laptop. This can eventually cause intermittant connections. Damn, I wish the thing were right in front of me. I'm sure I could fix it one way or another.

 

[CougTek]

First thing I thought was that you might have some sort of corrosion on a solder inside your lappy and since Jerusalem is a very dry area, the contact wouldn't work as it does in Toronto, where air is a lot more humid.

Just a thought.

At least you won't have far to walk to mourn about your laptop ;-)

 

[Piyono]

Hey, guys, thanks for the suggestions.
I should mention, first that it's not *my* laptop -- it belongs to the friend with whom I'm staying, so the only way I'm doing any mourning is if I get stuck with the repair bill (we split it in half).
As for a home-repair job, I was all set to solder the sucker save for one minor setback -- no soldering iron. My request for such a device yeilded - from the depths of said friend's tool box - a clunky, trigger-activated soldering "gun" sporting a fat, corroded tip. I miss my Weller.
Anyway, as I implied above, we gave up on the DIY method and sent the whole kit off to a Toshiba-approved $ervice center for apprai$al and repair ($$$).
No other Celeron laptop ever had it so good, so late in life.

Piyono