Power Jack Confusion!

[Gene]

For the last couple of weeks my T41 has been having a problem with what seems like the power jack. When I plugged in the AC power unit the green battery light wouldn’t light and it wasn’t charging. If I pulled it out and pushed it back in I can see the light quickly flash on and off and eventually if I kept playing with it the light would stay on and it would run off the AC unit. So it seemed pretty obvious the power jack died.

Since the jack is a separate unit (good job IBM!!!!!) I disassembled the machine to get to the jack. What now has me wondering is when I got it out, plugged in the charger and put a meter across the connections, I get a solid constant voltage between all positive and negatives at the connector. Even if I jiggle the plug the power stays constant.

Now I’m wondering if the jack is the real problem. Can somebody here clue me in to the internal working of the switch? Is it a single pole double throw switch (forgive me if I’ve got the nomenclature wrong, I’m and mech. eng!!) then it would make sense. The contact isn’t making connection with the other pole when the plug is pushed in. I see on EBay the jacks are cheap (around $3.75) so even if the find jack isn’t the problem I’m not going to loose very much, but then I’ve got to figure out what the real problem.

Any help the members of this forum will be greatly appreciated!! At 55 I’m a PhD student (!!) so I’m jointed at the hip to the machine!!

Thanks

Gene

[RealBlackStuff]

Not sure what switch you mean, the Power switch? That's only a push switch, hold it down and it makes contact, let go and it's off again.
As to the power jack: use pliers to bend a paperclip to a 90 degree angle at the end for only about 1/8". L shape looking.
With the battery removed!!! go into the powerjack and work that small angled piece under the bent contact inside the jack, and lift it up a bit, so it makes a better contact again. That normally does the trick.

[Gene]

Thanks for the quick reply!!!

Sorry for not being clearer, when I wrote "switch" I meant any switching function inside the power jack. Does the plug contact switch between two different contacts inside the jack when the plug is in verse when its not?

I’ve already tried the contact bending fix and while it did make the plug tighter in the jack, it still didn’t fix the problem. I’ll give it another try and see what happens. Since the jack is removed from the machine it should be easy. But this still doesn’t explain why I’m getting power (a little over 16 volts) out of the jack when I plug the charger into the jack. When I got it out of the machine I plugged the charger into the jack and put a volt meter across the positive and negative contacts in the plug that connects it to the motherboard. It looks like there are 2 negative and 2 positive connections on the motherboard plug and all show power (all negatives to positives) when the charger is plugged into the jack.

Is this normal, or is the jack broken and simple replacing it will remedy the problem. Or is power from all the contacts correct and there might be a problem in the charging circuit on the motherboard?

Thanks again,

Gene

[RealBlackStuff]

There is no switch involved at all (like you would find in e.g. an earphone jack, and which switches off the speakers).
The middle pin (+) in the jack connects to the hollow 'tube' of the plug. Bending this just the tiniest bit out of center could improve its contact.
The 'bent' contact (-) just presses against the outside of the plug. Over time this contact loses its springiness, and may make for poor(er) contact. Hence the trick with the paperclip to bend it 'up' again.
All jacks have 2 +cables and 2 -cables going to the plug that connects to the motherboard.
Unless it is physically broken, bending the contact(s) normally restores full functionality.

[Gene]

Ok, all that makes sense, but I still don’t understand how if the (-) contact isn’t making reliable connection with the outside of the barrel of the plug, why am I getting a solid voltage out of the jack? The voltage even holds steady if I twist and juggle the plug in the jack. Is there something I’m missing here or is there anything else that might cause this type of problem?

[Gene]

I just wanted to post a follow up to fixing (!) the power jack on my T41.

Senior ThinkPadder, your bent paper clip solution seems to have fixed the problem. Instead of using a paper clip I used a large pin (I’ve got tons of those things from building RC airplanes) and a magnifying glass to get it in behind the contact and pull it back out. But there was one thing that was originally making me feel like it wasn’t fixed. I forgot that once you plug in the charging unit it takes a few seconds for the green battery light to come on! So when I was plugging it in and not seeing immediately the light I was thinking it still wasn’t fixed.

Oh well, live and learn!!

Thanks Senior ThinkPadder for you help

Gene

[Harryc]

FYI..'Senior ThinkPadder' is a ranking name here based on total post count. The members name that helped you is RealBlackStuff.

[Gene]

Thank you, I stand corrected!!

So thank you RealBlackStuff for all your help.

Gene

[RealBlackStuff]

You're welcome!

PS: I'm from Dublin IE.

[keithsketchley]

With my x41 a flakey power jack seemed to result in the computer getting confused about the battery, battery symbol changing colour illogically.

No problem with a solid power connection.

(I'm running with the x4 Ultrabase as the power input when on the road, until I fix the jack, no battery problems.)

[keithsketchley]

Well, I now have flakey charging in vehicle with x4 Ultrabase, sometimes.

I suspect the combination of x41 and x4 Ultrabase or x4 Dock is sensitive to how well the latches pull the computer and base together (on rare occasion I get undocking notice or other anomally on desk with AC power).

I've tried with both a Targus and an IBM AC/DC adapter, same result.

I will try more with x4Dock and will look at feasibility of adjusting latching using the disassembled x4 Ultrabase I have.

Meanwhile I am squeezing the two together at each mating, including pushing to the left of the power button as that's the closest I can get to the connector and adjacent latches.

[keithsketchley]

I have to investigate more.

It seems that my Targus 70w air-auto adapter may be at least a key part of the problem, but I don't yet have parts to make a breakout to measure voltage. (I have a jack but not yet a plug.)

One obvious thing is to make sure latches click into place, they aren't all at the connector and the top cover of the x4 Ultrabase is a bit flexible (latches not right at screws).

One anomally I sometimes see is that disconnecting and reconnecting DC power changes display brightness as expected but not always charging state - that verifies to me that power is reaching the computer internals.

One feature of the latest power manager from Lenovo - v1.80 - is that the battery symbol in Windows' tray shows % when charging, duration when not.

[keithsketchley]

The problem I had occurs most often with a Targus power supply I’ve had for years in combination with my x4 Ultrabase, little problem with my IBM AC/DC power supply or with an x4 Dock.

I am measuring voltage loaded and unloaded (made a breakout cable), have not tried the x4 Dock with Targus, nor a different battery. Among two AC adapters, an IBM AC/DC supply, and the Targus there is a half volt range of voltages unloaded. The 12vdc adapters appear to keep the voltage steady but the Targus is a half volt lower than the IBM when unloaded, both above the nominal for the computer.

I am looking at ways of connecting a meter directly to the computer’s power jack, which is covered by the dock.

One variable I do not have a handle on is that there is significant capacitance in the computer’s power input, which is good on vehicle power because vehicle power has spikes in operation due switching of other loads, but may mean that the adapter is overloaded on initial powering of it so will sag initially (that’s hypothetical).

[keithsketchley]

The latest versions of Lenovo’s power manager software, versions 1.80 and 1.85 for sure, give much clearer indication of charging operation. The battery block in Windows’ tray area shows % if charging, predicted battery duration if not, a noticeable different in format – for example, 79% compared to 2:08.

The battery symbol in the status strip below the LCD is more complex, it is not a charging indicator as such. Per Lenovo:
- green means battery is in use and has enough power
- blinking green means has enough power but is being charged (I’ve never it blinking)
- orange means battery power is low but is being charged
- blinking orange means battery “needs to be charged” (doesn’t specify criteria, probably is a low level, I don’t recall seeing it even when I received an on-display warning of very low battery power.), beeps three times when it starts blinking.
So I interpret that as if the charging function is not working the indicator will still be green for a while, then it should blink orange as battery is depleted.
As well there is the battery status block in Windows’ tray area, see information earlier in this message.

It is a good idea to keep a spare fuse taped to the cord of your DC power supply if it has a fuse, such as the Targus 70 watt air/auto whose fuse is in the end of the auto plug.

[keithsketchley]

Also, there are several connections to come undone when you aren’t watching:
- plug into computer or base, IBM power supplies have ridges for better retention, some plugs of the same size grip the centre pin well, while others including Radio Shuck parts do neither.
- but their AC/DC adapter is not well designed, the connections of the DC input cable to the power brick and to to the plug into the lighter socket are easily dislodged
- plugs into lighter socket aren’t great either, unless special for aviation or marine
- and make sure your computer is well seated in the base/dock (it doesn’t guide in well enough, you have to push it down regardless (easiest with lid closed), and the base/dock is too flexible (best to be on flat surface).

[keithsketchley]

The “Power Manager” software has obscure features (much capability, such as turning display off with screen saver activation, and much information including voltage and full charge capacity (actual vs design), but poor UI), and there may be problems with some DC adapters not charging batteries when in use from vehicle 12vdc power (but probably charging if in standby/hibernation).

Also note it is unclear if the battery capacity indicator in Windows’ tray and the one in PM varies if aux battery (wedge) is used – I’ve seen it appear to switch from the total of both batteries to one when I was in PM dialogues (I understand from this forum that the computer will deplete the aux first then use the main, as well I observe it charges the main first and the capacity indicator first reflects the main battery then switches to the aux when the main is fully charged. Power Manager shows both batteries – it even claims to advise you of condition of each battery.)

PM v1.88 is available, my comments in this post are based on it.

And I see that the time-remaining mode of the capacity indicator when running on battery, instead of % remaining, may be a selectable option in Power Manager – I like that mode as I can see if power has been disconnected. (Right-click on the battery capacity indicator in Windows’ tray to see options or open PM or find it in Start|Programs|Thinkvantage.)
So there is much in the battery capacity indicator and/or PM, but you have to keep your wits about you when using them to accurately understand what you are being told.

Do beware that the calculations of such things as available capacity may well be approximate – time remaining to fully charge is way pessimistic.

And there is the question of whether or not spare batteries need to be recharged frequently. Some battery chemistries need that to avoid deterioration of capacity. For example, flooded lead acid batteries of the “deep cycle” type are more prone to that than “starting” type batteries, which are more affected by being substantially discharged. Lenovo’s Power Manager offers a choice between maximizing charge, which keeps battery above3 96%, and battery life (but does not specify the level of charge it gives for that).

[keithsketchley]

My post http://forums.thinkpads.com/viewtopic.php?f=3&t=93886 has information on dissassembling the x41 basic model to get at the power jack to resolder/replace.