Power Supply Problem?

[rvs053063]

When plugged into an outlet, my T23 still thinks its on a battery (but the battery doesn't drain). Periodically, the screen will glow brightly and the battery icon will disappear; this is when it realizes it is actually plugged in. However, these moments are brief. Usually, the screen is dimmed and the battery icon appears in the system tray. Would this be the power supply that needs to be replaced? Can I order the part from somewhere and do this myself? Or do you think it is something else entirely? I don't want to pay a big repair bill to IBM for something that is just an irritant.

Thanks,
Rick

[Thinkpaddict]

I would check the battery contacts both in the battery and on the computer. Just an idea...

[Kyocera]

If you know your way around a multimeter, check the output voltage, and if you have a decent one you can check the amps. Does it do this at all AC outlets?

Download yourself a Hardware Maintenance Manual, (click the Freq Asked Stuff in my sig) ohm out the battery connections also.
You could try pulling out the battery when it is plugged in to verify it is working (i really don't like that idea, but as a last resort maybe).

[Kyocera]

If you know your way around a multimeter, check the output voltage while the adapter is plugged into the wall, and if you have a decent one you can check the amps. Does it do this at all AC outlets?

Download yourself a Hardware Maintenance Manual, (click the Freq Asked Stuff in my sig) ohm out the battery connections also.
You could try pulling out the battery when it is plugged in to verify it is working (i really don't like that idea, but as a last resort maybe).

[rvs053063]

I've been able to determine:
1) Happens on all outlets, including plugged into an APC UPS that conditions the voltage. Multimeter indicates that the voltage coming into the brick is 119 volts and change, and the voltage exiting the brick is 16 volts and change. Both are where they should be.
2) I can boot without the battery, and run without the battery. However without the battery in the laptop, I will still get flickering, indicating that it wants to go to battery power, but finding no battery, it quickly reverts to AC power. Rapid flickering is intermittent, with prolonged periods of proper operation.
3) If the battery icon appears in the system tray, and the screen is dimmed, and I remove the battery, the laptop quickly reverts to AC power. I would think this would mean a bad battery, except for the fact that it still attempts to switch to battery power even when the battery is not installed.
4) Battery contacts look good.

Any further thoughts would be appreciated.
Thanks,
Rick

[Thinkpaddict]

One easy way to determine whether the problem resides in the hardware or in software and drivers is to use a bootable Linux CD.
You can use Slax for example, or Knoppix. Check the websites. You would basically burn a CD, and then boot from the CD (the hard drive is not accessed at all). If in doing so you weren't able to reproduce the problem, this would point to some sort of driver configuration issue, and you've cut your options by half. Let me know if you decide to try this and need help.

Regards.

[rvs053063]

This has done this since I got it back from IBM after they fixed other issues under warrantee. Of course, I got it back as the warrantee expired. Anyway, since then, I've repartitioned the hard drive and reinstalled XP a couple times; now the only thing on it is XP SP2 and Office 2000. Nothing else is installed on it.

Rick

[rkawakami]

2) I can boot without the battery, and run without the battery. However without the battery in the laptop, I will still get flickering, indicating that it wants to go to battery power, but finding no battery, it quickly reverts to AC power. Rapid flickering is intermittent, with prolonged periods of proper operation.

What you may be seeing here is the first stages of a failure in either the inverter board or the backlight since the flicker still occurs when the battery is removed from the laptop. If that is not the cause, then, with the power to the laptop off, push down on the lid closure switch a couple of times. You may have a dirty switch which is causing a loss/lack of power to the backlight.

What was the nature of the repair provided by IBM?

[rvs053063]

If the backlight alone flickered, this would make sense. However, with the battery installed, each time the light dims, the battery icon appears in the system tray indicating that the laptop is on battery power, though it never drains while plugged in. If the backlight alone was failing, then it wouldn't be tied to the battery icon appearing, right?

The IBM repairs as I recall were hard drive, screen and keyboard if memory serves. That was a couple years ago. When I got the laptop back, I just turned it on, made sure it worked, then stored it away as I had already started using another laptop. So with the problem being intermittent, I didn't notice it until long after I received it back, and couldn't very well go back to IBM at that late date to have them fix it.

How diffficult to replace an inverter? Where would I find the part?

Thanks,
Rick

[rkawakami]

If the backlight alone was failing, then it wouldn't be tied to the battery icon appearing, right?

Logically true, yes. But it also doesn't make sense that your battery is not draining when the screen is dim and the battery icon in your system tray.

How diffficult to replace an inverter? Where would I find the part?

It's fairly easy to get to the inverter. I did one a couple of weeks ago. You need to remove the four (six?) [edit: Three!] screws holding the LCD bezel around the front of the display. The hard part is unsnapping the bezel without breaking it. Once it's removed, the inverter board is at the bottom, just above the power switch. They can be found on eBay for $10-$20. Or you could try the Marketplace conference here at thinkpads.com. Part number should be 10L1402.

[rvs053063]

My mistake. The battery does drain. Looking at the battery icon, it doesn't appear to drain, but mousing over it does indicate battery loss. I don't think it stays in this state long enough (prior to switching back to AC) to drain enough power to change the appearence of the icon.

[rkawakami]

rvs053063,

Okay, I finally got around to rippping apart one of my 'dead' T23 systems a few hours ago and what I found may help with your problem. The way I see it, there can be four possible points of failure which could lead to symptoms which you describe:

1) The DC power jack is not properly screwed down. There should be a small screw on the bottom side of the laptop, just below the power jack. In addition to keeping the jack from moving around, there is an electrical connection on the bottom of the jack which is suppose to make contact with a matching metal pad on the circuit board on which it is mounted. (Note: it's NOT mounted on the motherboard; instead it is a small, thin board which runs the entire length of the back of the laptop and which holds all of the interface ports.) It appears to be a ground connection.

2) The DC power jack is defective. If the contacts inside the yellow power jack are dirty/corroded/high resistance, this could cause your TP to not see the external DC voltage. If this is the case, the jack is replaceable by simply unscrewing it. They can be found on eBay.

3) Said DC power jack terminates inside the laptop at a four-pin plug. There are a pair of wires for both the power (+16V) and ground. I can only assume that IBM uses the pair of wires for increased current-handling capability. The contacts inside the jack located on the motherboard could also be dirty/corroded/high resistance. If the plug is removed, you can inspect/clean the four pins inside the connector.

4) A component on the motherboard (most likely a fuse) is not properly soldered down. The fuse itself is most likely okay; it just may not be fully/properly connected. In my case, the fuse was blown and it prevented the laptop from being powered externally via the DC power jack or a docking station. It works fine with the batttery but it will never charge.

[rvs053063]

The power jack is screwed down tightly. The contacts that it plugs into on the mother board are clean. It did seem that the contact inside the power jack was dirty, so I cleaned it with sandpaper to its original shiny surface, and so far so good. The laptop has yet to switch to battery power. This doesn't explain, however, why, upon removing the battery, that the laptop wouldn't just shut down when it lost AC contact since it didn't have a battery to fall back on. Any ideas? Also, the power jack can't be easily replaced as it wouldn't slide out the rear, and it doesn't move forward with the circuit board and fan in the way. Hopefully, it won't come down to that and the problem has been fixed. Thanks!

Rick

[rkawakami]

It did seem that the contact inside the power jack was dirty, so I cleaned it with sandpaper to its original shiny surface, and so far so good.

There are actually TWO contacts inside the power jack; the 'pin' in the center and the metal 'tongue' toward the bottom. Make sure both are clean and that no metal debris is left inside.

The laptop has yet to switch to battery power. This doesn't explain, however, why, upon removing the battery, that the laptop wouldn't just shut down when it lost AC contact since it didn't have a battery to fall back on.

It may have been that the contact(s) were dirty enough that the laptop had problems sensing the voltage, yet still allowed enough current to flow through when powering the system without the battery.

Also, the power jack can't be easily replaced as it wouldn't slide out the rear, and it doesn't move forward with the circuit board and fan in the way.

The power jack lifts straight up and out, after being pried up since there are two clips on the bottom which secure it to the board (in addition to the screw). You do need to unplug the fan but it is not necessary to remove either the fan/heat sink nor the motherboard. What just worked for me is to take a small screwdriver and put it into the upper left corner of the rear of the jack and using the heat sink, lever it up. See the picture:

http://www.rkawakami.net/ibm_600x/image ... _jack1.jpg

Once it is removed, look on the bottom of the jack and you will see a contact spring. There will also be a metal pad on the board it was mounted on. Make sure both are clean.

[rvs053063]

My PC doesn't look like that. The yellow jack on my T23 is actually embedded underneath the plastic molding of the rear of the case. It can't be lifted up because the case is in the way. It really doesn't matter at this point because after a number of hours of use, the PC has behaved since cleaning the contacts. Thanks for everyone's help.

Rick

[tom_k]

pardon me for jumping in,
hoping to find the solution for an old Problem :

Two T21 boards working only on battery.
Removing main or ultrabay battery powers them down instantly,one can`t charge the battery ,
the other does it well and the led shows the right battery condition.
All other led`s stay dead, no matter what i try,
also on the port replicator or with another subboard etc.
So i think it can only be "something" wrong on the board

Sun Sep 10, 2006 10:07 am

4) A component on the motherboard (most likely a fuse) is not properly soldered down. The fuse itself is most likely okay; it just may not be fully/properly connected. In my case, the fuse was blown and it prevented the laptop from being powered externally via the DC power jack or a docking station. It works fine with the batttery but it will never charge.

@rkawakami
Though not the same, one board does even charge, it might possibly be a problem in the "neighbourhood".
I have inspected the mobo, but i don`t really know what to look for,
so it would be nice if you could specify how this fuse looks like or where it is located.

@rvs053063
Nice to hear that your T23 is running well again :)

regards tom_k

btw, in this thread at ThinkPad-portal.de
3 boards have similar symptoms as mine ,
but showing 190: critical low battery error

[rkawakami]

My PC doesn't look like that. The yellow jack on my T23 is actually embedded underneath the plastic molding of the rear of the case. It can't be lifted up because the case is in the way.

Ah, it sounds like you haven't removed the keyboard bezel then. Three screws on the bottom and two on top should release it (along with some careful prying apart). That and the hinge cover assembly too! I forgot that my T23 is totally disassembled. Good luck with the system!