Thinkpads Forum

I did not know that Lenovo changed the charger for the W540. It is flatter than the previos W series and uses a plug just like the Carbon, flat and not round.

Guess it was needed due to the W540 being so thin.

Greg Gebhardt wrote:I did not know that Lenovo changed the charger for the W540. It is flatter than the previos W series and uses a plug just like the Carbon, flat and not round.

Guess it was needed due to the W540 being so thin.

Every new Thinkpad laptop uses the new charger

Do you post this, because you now own one?
If you own one, and you have a simple ohmmeter or multimeter, then please measure resistance between signal pin and shell (neutral/return).

I did not realize they had changed the charging port, thanks.

My multimeter is at work but I will check this out when I get to the office. What is the purpose of this measurement?

automobus wrote:Do you post this, because you now own one?
If you own one, and you have a simple ohmmeter or multimeter, then please measure resistance between signal pin and shell (neutral/return).

I just received my W540. The power connector is rectangular, and the resistance from the center pin to outer shell is 1.9K OHMS. This resistance tells the computer it's a 170W power adapter, as opposed to a 90W power adapter.

The W540 power adapter is slightly smaller, and thinner than a W520 power adapter. Both are 20V, 170W.



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http://bob-ayers.smugmug.com/Other/Leno ... 191-XL.jpg (180KB)

Admin edit: Changed large inline images to links. P.S. It was thoughtful to put a picture warning in your post but it does NO good as it won't be seen until the thread is loaded. In other words, a warning is only good if it appears in the ORIGINAL subject line of the thread.

Takeda, thank you very much for your good work. Those are nice pictures. I refer to your finding and added it to our discussion in the W500/W700 forum.

Takeda wrote:The W540 power adapter is slightly smaller, and thinner than a W520 power adapter. Both are 20V, 170W.



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http://bob-ayers.smugmug.com/Other/Leno ... 189-XL.jpg (225KB)

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http://bob-ayers.smugmug.com/Other/Leno ... 190-XL.jpg (125KB)

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http://bob-ayers.smugmug.com/Other/Leno ... 191-XL.jpg (180KB)

Admin edit: Changed large inline images to links. P.S. It was thoughtful to put a picture warning in your post but it does NO good as it won't be seen until the thread is loaded. In other words, a warning is only good if it appears in the ORIGINAL subject line of the thread.

Thanks Bill!

So why the change in connector? To piss off those that already have an assortment of chargers? Oh wait; those are not likely to buy a W540 in the first place due to it's crappy keyboard layout.

You could get this power tip adapter:
http://www.amazon.com/gp/search/url=sea ... ds=0b47046

I tried that Patuoxun adapter dr_st mentions with an old classic 90W brick, the W540 didn't do anything with it. That is, it didn't recognize there was line power, and the battery continued to drop even when the laptop wasn't doing anything much. I'm guessing the adapter passes through the signal pin, and that pin is N/C in the old 90W brick with round tip. And that the W540 tests the darn pin before turning on the juice.

I have an external battery pack that came with the old style tip, very good for long flights. I reckon it can deliver 4.5A @ 20V (90W), which would mean with the old round tip it should leave the signal pin N/C. No doubt it does leave the signal alone, so that is why it worked fine with my old T series. But if I splice a slim tip on, I guess I should fiddle the resistance of that pin. The question is, should I give it 1.9kohms, like the 170W brick I usually use? Or 550 ohms, like a 90W pack with a slim tip is supposed to have?

Does anyone know what a W540 would do with a slim tip that could only deliver 90W? I don't really need it to charge the battery, so long as it stops *discharging* the battery.

Has anyone had any success in finding an adapter to convert the old big round plug 170W adapters (eg. from a W520) to the slim adapters for the W540?

I tried one of the adapters mentioned here (for the Carbon X1's). I had to trim out the internal lugs on the 170W adapter plug. But the W540 still doesn't recognise the adapter (probably as the resistance is not being correctly wired through the adapter).

I'd love to find some type of adapter so I can reuse a couple of 170W W520 power bricks I've got sitting around, rather than having to drag the new W540 adapter around.

Cheers.

Greg Gebhardt wrote:Guess it was needed due to the W540 being so thin.

...not

The base of the T60p/T61p/W500 used to be thinner. They changed it to make it uniform, as all new ThinkPads have the rectangular charger, since the Ultrabook models (X240/T440/X1) didn't have enough space for the old round charger.

kidhazy wrote:I tried one of the adapters … the W540 still doesn't recognise the adapter

Do you own a electrical multimeter? (If not, then I suggest you get one.) Did you check that electricity goes through your plug converter? I assume you bought some shoddy aftermarket garbage instead of genuine Lenovo converter.

loudmouth opinion:
I spent ten dollars to buy my cheapo multimeter. It is one of the best purchases I ever made. I wish I bought it five or six years sooner! It takes the mystery out of so many situations. It can be used with: fuses, brownouts, light fixture unlabeled wires, batteries, toys, and other things.

most any guy will have a VOM.. but there is a signal that tells the AC adapter to either charge or not.. right..? just guessing here since its been years since i looked at a hardware manual for a thinkpad..

when i was thinking of getting an X1 carbon i saw some round to square adapters on ebay..
and maybe amazon, too..
not expensive..
assuming the E's are the same and the signaling is the same..

IRT the survey for T400 owners..
i have two of them..
what is the question..?
and why not just do a poll..?
in the appropriate conference..

automobus wrote: Do you own a electrical multimeter? (If not, then I suggest you get one.) Did you check that electricity goes through your plug converter? I assume you bought some shoddy aftermarket garbage instead of genuine Lenovo converter.

Yes, got a multimeter - but didn't use it as the W540 battery status would change from saying "Battery is in good condition" to something like "Power adapter supply not adequate" so I assumed there was at least the electricity is still going through.

Based on the article here http://www.thinkwiki.org/wiki/Power_Con ... Signal_Pin I'm assuming it's not able to detect that it's detected to a 170W adapter (or possibly it checks for a W540 specific 170W adapter).

I'll pull out the multimeter tonight and see if I can measure the resistance between the central signal pin with the adapter connected.

Fired up the multimeter.

The old W520 170W adapter has a resistance of 1500 ohms between outer ring and center pin.

The new W540 170w slim adapter has a resistance of 1900 ohms between the outer side and center pin.

The adapter I bought has a resistance of 555 ohms. Which according to http://www.thinkwiki.org/wiki/Power_Connector#slim_tip matches a 90W 'adapter' signal.

So looks like the W540s will be looking for something with resistance of 1900 ohms plugged in to it's power connector to detect a 'real' adapter.
(I must have missed this on the ThinkWiki PowerConnector page - 'cos a W520 170W adapter is never going to provide the right 'signal' resistance)


Maybe it's time for a bit of a hack on the adapter I bought.

So I pulled my adapter cable apart. At the slim-tip end there was a small 550ohm resistor between the center pin and outside (ground) (which told the W540 it was a 90W PSU)

I cut it out and put in a 1500ohm resistor. A bit of hit-sink wrap and tape, and I now have a big-barrel to slim-tip adaptor that shows all power-adapters as 170W adaptors.

I can now reuse my old 170W and 135W adapters to keep the W540 chugging.

(I also played around connecting the center pin at both ends of the adapter (therefore passing through the 'resistance') this worked for the 170W adapters, but the 135W adapters were deemed not to have enough power for the W540 - so I 'locked' it in as a 170W adapter via the 1500ohm resistor)

Thanks for sharing that info!

Can anyone with a genuine 0B47046 confirm if the center pins are connected, passing through the resistance of the legacy charger?

If it does this, it makes the high price a bit more palatable, until the Chinese get their act together.

Around the WWW is confusion regarding 0B47046. I do not know what it is, what it looks like. I wonder if it is the Option Part Number or Marketing P/N assigned to FRU 03X6261, ASM 0A36037. If you do buy real 0B47046, then please tell us what it is.

FRU 03X6261 (ASM 0A36037) is known to have three wires/three conductors. A aftermarket device of fixed resistance between output-plug signal pin and ground and which is claimed 'compatible' with 03X6261 or 0A36037, is garbage and any seller of such is a fraudulent scumbag.

edit: Thank you pixeluk! I was confused because I saw eBayers with photos of sealed Lenovo box, but use stock photo of other parts; photos of genuine part in generic listings, and so on.

automobus wrote:Around the WWW is confusion regarding 0B47046. I do not know what it is, what it looks like. I wonder if it is the Option Part Number or Marketing P/N assigned to FRU 03X6261, ASM 0A36037. If you do buy real 0B47046, then please tell us what it is.
FRU 03X6261 (ASM 0A36037) is known to have three wires/three conductors...

Thanks, I think that answers my question. Have you successfully used a genuine Lenovo [insert preferred p/n here] adapter on a >90W x40 series laptop?

Maybe the 0B47046 code is a UK thing.

http://shop.lenovo.com/gb/en/itemdetail ... 80D5139C82

edit: 0B47046 == 03X6261. The following link won't last forever but clearly shows the part number 03X6261 in the zoomed view of a "refurbished" (read: opened box) 0B47046. No wiser as to where the p/n 0B47046 comes from though..

http://www.ebay.co.uk/itm/Lenovo-0B4704 ... 58b297cd06

Slightly bad news re the 0B47046/03X6261.

It allows you to use a W530 170w adapter (after you knock out the lugs) on the W540 but it's only detected as a 135W. I don't know if performance will suffer for this but I'd imagine it will.

Very irritating that they messed with the resistances on the x40 series adapters and didn't build in backwards compatibility.

This means that the Chinese cloners have an opportunity to make a better than standard converter by wiring in a 1.9k ohm resistor and using 2 wires. Hopefully they read this forum!

This is the product label by the way for automobus:

http://i57.tinypic.com/r0p07d.jpg

Mod edit: picture too large, changed to link.
Please read Rules of the Road, Section 5: http://forum.thinkpads.com/viewtopic.php?f=16&t=14339

edit: sorry about the pic. rules noted!

pixeluk wrote:Slightly bad news re the 0B47046/03X6261.

It allows you to use a W530 170w adapter (after you knock out the lugs) on the W540 but it's only detected as a 135W. I don't know if performance will suffer for this but I'd imagine it will.
[...]

Why would it? I've yet to see reports that the W530 or W520 suffers performance-wise from a 135W adapter.

Performance doesn't change when you use a lower wattage AC Adapter (or "charger")? Really? (Send a link!)

My problem is that airplanes with 110VAC plugs don't work with the large-wattage Lenovo adapters. I've presumed that the adapter wants to draw too many amps and a safety cutout activates on the airplane-side of the receptacle and would love to find a solution. If I can just use a smaller wattage adapter, well, problem solved!

smap77 wrote:Performance doesn't change when you use a lower wattage AC Adapter (or "charger")? Really? (Send a link!)

That is for using the 135W instead of the 170W (on W520 / W530). I've yet to see anyone who reports reduced performance with the 135. The 90 however does not work at all. It can only charge the W520 when it's not turned on. I use a W520 myself and a lot of people around me use a T530. I have the 170W adapter, they have the 135W. My W520 works perfectly fine with those 135W adapters.

smap77 wrote: My problem is that airplanes with 110VAC plugs don't work with the large-wattage Lenovo adapters. I've presumed that the adapter wants to draw too many amps and a safety cutout activates on the airplane-side of the receptacle and would love to find a solution. If I can just use a smaller wattage adapter, well, problem solved!

Did you try? The outlet can't smell the maximum power consumption of connected hardware. It probably has a fuse that will activate when a certain current is exceeded, but you will only ever get close to that 170W (or 135) when you have a maxed-out W520 that's under full load (CPU and GPU) while also charging the battery. Just watching a video or doing text work should work perfectly fine and the adapter will draw <30W from the outlet.