Thinkpads Forum

I have an X40 that I've had for about 1.5 years (purchased refurbished from IBM in Dec 05).

The other day, after I plugged in the laptop, I heard a soft popping sound coming from the A/C adapter brick. I unplugged it and looked around to see if there was water or damage anywhere. There wasn't so I tried plugging in again... and all was well.

Two days later, I heard a popping sound again and I unplugged it. Now, when I plug it in, it doesn't seem as if the AC adapter is working. The laptop won't power up without the battery and it wont charge the battery when the battery is in place (The battery is still gets a few hours per charge, so i dont think its a battery problem).

So my quesiton is where do I proceed from here? I don't have any warrantees since the Lenovo refurb warrantee is only 90 days. Should I try to buy a new A/C adapter to see if it was the AC adapter that fried/ or is there another way?

If it matters, I used the A/C adapter from my gf's 600e the previous evening. I'd used this A/C adapter tons of times in the past and never had a problem... do you thinkt hat might have fried my mother board? (maybe the charging circuit or soemthing?)

Anything else I can do? Thanks in advance for any insights.

The X40 appears to use the 54W AC adapter (IBM calls it 56W, but by the printed rating on the adapter, 16V @ 3.36A, my math says it's closer to 54W). The 600E shipped with the same wattage adapter. So I don't think you are overloading the adapter, unless you have a bunch of other equipment plugged into your laptop.

It is possible that something on the laptop motherboard has been damaged. Either the charging circuit or maybe just a fuse has blown. If you attach a known good adapter (see next point) and your battery does not charge, then something is up on the motherboard.

The only way I know of safely checking the power supply would be to use a voltmeter and measure the voltage at the end of the plug. You should read slightly higher than 16V. Most of my adapters read 16.7V. The current draw is harder to measure since you would need to insert the current meter inline with the plug.

Buying a multimeter (voltage, current, resistance) will probably cost you just the same as a new adapter, so it's your call. I will say that having a meter is useful for other purposes besides checking your AC adapter.

Thanks for your prompt reply.

Is there anyway to easily check the condition of the fuse?

I would imagine that there are SEVERAL fuses on the motherboard, if it's anything like the T2x and 600 systems I've looked at. There should be one main fuse protecting the DC input jack and two at the main battery terminals. You would have to disassemble the laptop to get at the motherboard. You then have to locate the fuse(s) and test them with an ohmmeter (resistance). As the fuses can be packaged in a couple of different styles, here's a picture of the two next to a T23 battery terminal:

http://www.rkawakami.net/ibm_t2x/main_fuses.jpg

Here's a picture of the main DC input fuse (look at the top for an "F2" designation; the actual fuse is just to the left):

http://www.rkawakami.net/ibm_t2x/let.jpg

Also visible in that last picture is a thermal fuse. It's the green looking rectangular "plate" marked "7X7", above and to the right of the black circle.

With an multimeter in the lowest range ohms position and the motherboard un-powered, connect the meter leads across the ends of the fuse and you should read 0 ohms. Anything more than 1 ohm and the fuse is bad. Finding a replacement can be tricky. It's not something that you can find at your local Radio Shack store (I'd be quite surprised if they stock surface mount fuses). I have been able to find replacement fuses at mouser.com or digikey.com. Actually replacing the fuse is even harder if you haven't had experience with dealing with tiny SMT (surface mount technology) devices. You need a low wattage soldering iron (about 25W), good eyes, a steady hand, tiny tweezers, good eyes (did I say that already?) and sometimes three hands.

thanks for your reply. I guess the short answer to my question for an easy way to check the fuse would be no

The procedure you wrote seems a bit involved. here's to praying that it is the A/C adapter that is broken... i'll see if i can find a voltmeter to borrow tomorrow.

thanks again.

Don't forget the simple solutions:

I got a noise upon plugging in the AC adapter on my old 600 some months back. Not having heard your noise, I don't know if it was similar, but mine was seemed snap-like. I didn't leave it plugged in long, but I do seem to recall that it didn't seem like the thinkpad was properly detecting that the AC adapter was connected.

It turned out that the AC cord on my adapter was breaking, and the snap I heard was one of the wires making and breaking contact as it flexed at the exact edge of the molded strain relief. That cord was old when I bought the machine, and some of the strain relief lugs were broken, so the cord was able to flex more.

I replaced that cord (about $8), and my snapping was gone. I make a point of leaving a little slack at the strain relief now when I wrap up the brick, so as to avoid prematurely inducing the same problem again.

If you tend to pull the cords tight around the brick when wrapping up as I used to do, take a good look at that molded AC cord - maybe you've got a broken cord.

If nothing else, it's easy to check and cheap to replace; might as well eliminate the simple things first.

Rob

I couldn't find a voltmeter to borrow.. but I did the next best thing..

I took the AC adapter apart..

I noticed that the connector that the power cord plugs into was loose and there was a burnt solder point (one of the connecting points to the board was blackened and kind of loose).

I realize that I probably need a new AC adapter, but is there any chance that there is something malfunctioning on my laptop that somehow caused this to happen? Or is it likely that I probably found the root cause of my problem?

Thanks

That sounds like a bad cold solder joint. If you have a soldering iron, clean up that burnt area, and resolder it, using plenty of tin. Resolder the other points as well while you're at it.
Bet that solves your problem.

PS: it goes without saying to make sure that adapter is UNplugged when you do that!

the black area was burnt pretty bad. it looked like the board was also burnt and i was able to lift up the copper slip where the solder bonded to.

I cleaned it as best i could with what I had (which is not much), soldered the points and put it back together.

Right now its charging.. so it looks like it was the A/C adapter that was bad.

I guess I'll invest in a new A/C adapter.. btw. is there any harm in running my A/C adapter as is for now? Any detriment to my laptop or will the solder point just burn again if i didnt clean it enough?

Thanks for everyone's help!

Just in case the AC adapter you received from IBM (I assume it came with the laptop) is on their AC adapter recall list:
http://www-307.ibm.com/pc/support/site. ... ECALL.html

By the way, checking the onboard fuse sounds like a really good idea. If I had known earlier maybe I could still fix my first laptop (Averatec 3120v) before I sold it as parts two years ago.

The adapter itself was probably the main root cause. I doubt that anything on your laptop could have made the adapter wear like that unless you are connecting another 20-30W of accessories. It sounds like a simple case of a bad solder joint, along with age and stress, which led to the failure.

By all means, check to see if your adapter is a 02K6549 model as teetee has pointed out. Those were recalled about a couple of years ago for overheating. Until you replace your adapter with a "new" one, I would NOT leave it plugged in while unattended.