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W520 requires 170W AC adapter

W500/W510/W520 and W700/W701 Series
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Stinkpadda
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Re: W520 requires 170W AC adapter

#91 Post by Stinkpadda » Wed Aug 01, 2012 7:07 am

I measure 10.0 kOhm between the outer metal cylinder and the center pin on my 65W PSU, regardless of whether the power connector is plugged in or not. This would suggest that there is just a resistor between the center pin and earth, probably somewhere inside the tip.

Lenovo Power Manager correctly reports it as a 65W PSU.

20.2 V potential between inner and outer cylinders. Not that it matters.

The third-party PSU I bought has a detachable tip. It has infinite resistance between tip and ground, regardless of whether it is joined to the PSU cable or not. This would suggest that there is no contact between center pin and earth anywhere.

Lenovo Power Manager reports it as a 90W PSU, while it is actually a 150W unit.

zsero writes:
The resistance between the pin and the outside metal is 10K on a normal TP adapter. It is 1.5K on the W520 adapter!
What is a "normal TP adapter"? 65W?

Anyone with a 135W unit around care to make a measurement?

Thanks in advance
/Some guy

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Re: W520 requires 170W AC adapter

#92 Post by zsero » Wed Aug 01, 2012 7:12 am

Stinkpadda wrote:I measure 10.0 kOhm between the outer metal cylinder and the center pin on my 65W PSU, regardless of whether the power connector is plugged in or not. This would suggest that there is just a resistor between the center pin and earth, probably somewhere inside the tip.

Lenovo Power Manager correctly reports it as a 65W PSU.

20.2 V potential between inner and outer cylinders. Not that it matters.

The third-party PSU I bought has a detachable tip. It has infinite resistance between tip and ground, regardless of whether it is joined to the PSU cable or not. This would suggest that there is no contact between center pin and earth anywhere.

Lenovo Power Manager reports it as a 90W PSU, while it is actually a 150W unit.

What is a "normal TP adapter"? 65W?

Anyone with a 135W unit around care to make a measurement?

Thanks in advance
/Some guy
I think all thinkpad adapters are 10K, except the W520 one which is 1.5K. I don't know about the 135W one. I think you can just insert a 1.5K resistor into the back of the laptop and use the generic adapter. Do you want to try it?

Stinkpadda
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Re: W520 requires 170W AC adapter

#93 Post by Stinkpadda » Wed Aug 01, 2012 6:20 pm

Good point. It doesn't matter if the system believes it to be 135W or 170W.

I shall try it as soon as I get the time. Have to do some things first that require an unexperimented and undestroyed power tip. Check back in a few days.

automobus
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Re: W520 requires 170W AC adapter

#94 Post by automobus » Wed Aug 01, 2012 8:38 pm

summary:

65 watt
rkawakami wrote:I've measured the center pin with respect to ground; the metal on the outside of the DC plug. There's no voltage present when the supply is plugged in but there is a resistance of 10Kohms when it's unplugged.
http://forum.thinkpads.com/viewtopic.ph ... 76#p603576
zsero wrote:I think I found the trick! The resistance between the pin and the outside metal is 10K on a normal TP adapter.
http://forum.thinkpads.com/viewtopic.ph ... 98#p679798
Stinkpadda wrote:I measure 10.0 kOhm between the outer metal cylinder and the center pin on my 65W PSU, regardless of whether the power connector is plugged in or not.
http://forum.thinkpads.com/viewtopic.ph ... 78#p682578



90 watt
geoffrey wrote:I tried covering half of the inner surface of a 90W adapter with sellotape, and then inserting it so that the sellotape breaks the electical contact with one of the two inner electrodes but not the other.

So nothing special in the 90W tip as far as I can tell.
http://forum.thinkpads.com/viewtopic.ph ... 15#p671815
Stinkpadda wrote:The third-party PSU I bought has a detachable tip. It has infinite resistance between tip and ground, regardless of whether it is joined to the PSU cable or not.

Lenovo Power Manager reports it as a 90W PSU.
http://forum.thinkpads.com/viewtopic.ph ... 78#p682578

I can confirm that the signal pin is not connected to ground.



135 watt
sunhongyi18 wrote:short the 1blue and 7black

after this modification my w510 identifies all attached PSU as original 135W PSU

Best Regards! 
SUN 
http://sunhongyi.outuo.net/w510/2.jpg
http://sunhongyi.outuo.net/w510/1.jpg
http://forums.lenovo.com/t5/W-Series-Th ... 845#M12703



170 watt
zsero wrote:It is 1.5K on the W520 adapter!!! That's it! That's the only difference (+the plastic).
http://forum.thinkpads.com/viewtopic.ph ... 98#p679798



230 watt

Anybody have a source for this one?

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Re: W520 requires 170W AC adapter

#95 Post by zsero » Thu Aug 02, 2012 6:26 am

OK I can just confirm, that I measured 4 different 65W adapter and all of them were 10K.

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Re: W520 requires 170W AC adapter

#96 Post by Stinkpadda » Tue Aug 07, 2012 4:22 am

Right. I am confused.

I got myself an adjustable potentiometer and soldered it to a butchered power tip. Changed the resistance around a bit and looked at what Lenovo Power Manager said under the Battery tab.

These are my findings:

0 ohm = 120 W
1500 ohm = 120 W
2000 ohm = 120 W
2500 ohm = 50 W
3000 ohm = 50 W
4000 ohm = 50 W
5000 ohm = 50 W
6000 ohm = 50 W
7000 ohm = 65 W
8000 ohm = 65 W
9500 ohm = 65 W
Infinite ohm = 90 W

The last one I did not measure, my trimpot only went to 9.5k.

So... what's the deal with the 135 W and 170 W adapters?

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Re: W520 requires 170W AC adapter

#97 Post by Stinkpadda » Tue Aug 07, 2012 4:38 am

Here are some pictures:
Image

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Re: W520 requires 170W AC adapter

#98 Post by Stinkpadda » Tue Aug 07, 2012 4:44 am

Oh, hey - the W510 reports the PSU as 135 W with 0 ohm?!?

I did the first list on my x61s. It apparently differs between computers!

Note: The x61s uses the latest Lenovo Power Manager, so it cannot be a software thing. I suppose the BIOS tells the Power Manager the wattage and the x61s was never expected to run from a >120W PSU.

Or something.

I shall make an updated list on the W510 once its drained battery gets charged. I need to unplug and tweak the trimpot every time, just twisting the screw when it is connected to the computer makes no difference in the wattage note.

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Re: W520 requires 170W AC adapter

#99 Post by Stinkpadda » Tue Aug 07, 2012 6:52 am

This is what I got from the W510:

0 ohm = 135 W
1000 ohm = 135 W
1500 ohm = 135 W
2000 ohm = 135 W
2500 ohm = - (empty watt line, but it says "charging")
3000 ohm = - (empty watt line, but it says "charging")
4000 ohm = - (empty watt line, but it says "charging")
6000 ohm = - (empty watt line, but it says "charging")
6500 ohm = 65 W
9500 ohm = 65 W
Infinite ohm = 90 W

My interpretation:

< 2500 ohm means "max capacity PSU". This should be tested with a 170 W and 230 W system as well.

2500 to 6500 ohm means 50 W which for the W510 is too little to be of any use so it does not report any PSU at all. Although it does say "charging" further down on that tab, the remaining time fluctuated wildly.

> 6500 ohm (but less than some unknown high value) means 65 W.

No connection means 90W.

So there you have it - if you want to modify your power connector so that the system thinks it is a full-powered unit and does not throttle the CPU, just short-circuit the center pin to ground.

I take no responsibility for anything you may destroy. I suspect that you may blow a lesser PSU or make antimatter shoot out of your USB ports or whatever, so do not rely on me for accurate advice. I am not educated in electronics and most of what takes place under the plastic cases of electric devices are magic to me.

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Re: W520 requires 170W AC adapter

#100 Post by Stinkpadda » Tue Aug 07, 2012 7:21 am

Since I had a bunch of power tips, I ended up doing this:
Image

I might add that my PSU is a 150 W unit (noname brand, but still), so do not expect it to cause any problems.

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Re: W520 requires 170W AC adapter

#101 Post by automobus » Tue Aug 07, 2012 11:18 am

Stinkpadda wrote:Oh, hey - the W510 reports the PSU as 135 W with 0 ohm?!?

I did the first list on my x61s. It apparently differs between computers!

Note: The x61s uses the latest Lenovo Power Manager, so it cannot be a software thing. I suppose the BIOS tells the Power Manager the wattage and the x61s was never expected to run from a >120W PSU.
X61s is two years older than W510. In the time when ThinkPad generation α61 was engineered and produced, only 65 and 90 watt AC Adapters existed. I think, their power subsystem is unable, or not programmed, to detect newer power supply signals. W510 is not only newer, but specifically made for use with the 135 watt supply. W520's 170 watt supply is even newer, and so it will probably be recognised as 135W by a W510.


Code: Select all

resistance signal chart
0 Ω              = 135 W
(0 Ω, 1.5 kΩ)    = uncertain
1.5 kΩ           = 170 W
(1.5 kΩ, 2.5 kΩ) = uncertain
[2.5 kΩ, 6 kΩ]   = reserved for 50 W, not used in any released products?
(6 kΩ, 6.5 kΩ)   = uncertain
[6.5 kΩ, 10 kΩ]  = 65 W
(10 kΩ, ?)       = uncertain
∞ Ω              = 90 W
I think, the elusive 230 watt adapter is in one of the uncertain ranges.

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Re: W520 requires 170W AC adapter

#102 Post by Stinkpadda » Thu Aug 09, 2012 11:24 am

Did you have that table this whole time? =/

geoffrey
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Re: W520 requires 170W AC adapter

#103 Post by geoffrey » Fri Aug 10, 2012 6:07 am

Stinkpadda wrote:So there you have it - if you want to modify your power connector so that the system thinks it is a full-powered unit and does not throttle the CPU, just short-circuit the center pin to ground.

I take no responsibility for anything you may destroy. I suspect that you may blow a lesser PSU or make antimatter shoot out of your USB ports or whatever, so do not rely on me for accurate advice. I am not educated in electronics and most of what takes place under the plastic cases of electric devices are magic to me.
This is excellent sleuthing, Stinkpadda! Very useful indeed, and fits perfectly with all the previous findings of others. It looks like automobus pulled that table together as a summary of your results. I have a W520 and I also have one of those 90W tips from a cheapo adapter, so I'll see if I can replicate the same result by shorting the centre pin to the outer-casing wire and will report back (with fingers crossed that I don't blow the W520 power port!).

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Re: W520 requires 170W AC adapter

#104 Post by zsero » Fri Aug 10, 2012 6:28 am

It's such a pity we have to short with the _outer_ part, as if we had to short with the inner one, we could just put some tiny wire at the back of the computer and use any adapter!

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Re: W520 requires 170W AC adapter

#105 Post by geoffrey » Sat Aug 11, 2012 6:16 am

Unfortunately, the el cheapo 90W tip I have is exceedingly difficult to unravel. Having scraped/cut away as much of the plastic as possible, I'm left with a prong connected to the middle pin, but coiled around this extremely tightly is a sheet of metal connected to the inner face. There seems to be a thin layer of plastic insulating the two, but there's not enough space to solder without shorting the inner face and the middle pin. I'd have to try to melt some of the remaining plastic out in order to get a purchase on the coiled sheet and prise it off, if it can be separated at all. Won't now be able to do this for a couple of weeks (going on holiday), but will report back if I manage to get anywhere further with this tip. Does anyone know a good source of tips that might be more easily modified?

I should just say, too, that this cheap tip originally had the middle (signal) pin connected to the inner face electrically, and my W520 detected it as a 90W. This seems to be very dangerous to say the least. If anyone adopts the solution of shorting the pins inside the computer, all I can say is, beware of cheap tips, because that would have shorted the + and the - as well, and could well blow something vital either in the adapter or the computer.

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Re: W520 requires 170W AC adapter

#106 Post by automobus » Sun Oct 21, 2012 4:06 pm

Thank you, geoffrey, for the warning about dangerous aftermarket DC plug tips.


Stinkpadda wrote:0 ohm = 120 W

Oh, hey - the W510 reports the PSU as 135 W with 0 ohm?!?
I did the first list on my x61s. It apparently differs between computers!
Thank you, Stinkpadda, for your experimentation. I very much appreciate your findings. I just found a relevant article in the Lenovo Community Knowledge Base.
Accessory_Gary wrote:Some model of Thinkpads will recognise the 135 watts adapter as 135 watts, while other may recognise it as 120 watts or 90 watts
Lenovo Thinkpad Power Adapter compatibility list
(print view)

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Re: W520 requires 170W AC adapter

#107 Post by drewwesley » Wed Oct 31, 2012 6:35 pm

What's the affect on power demand if I go into the bios, turning off two cpu cores, and using integrated graphics (ie. travel mode, turning the W520 into a T520). It would be really nice to carry a 90W slim adapter instead of the 170W brick we all complain about.

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Re: W520 requires 170W AC adapter

#108 Post by zsero » Wed Oct 31, 2012 7:18 pm

drewwesley wrote:What's the affect on power demand if I go into the bios, turning off two cpu cores, and using integrated graphics (ie. travel mode, turning the W520 into a T520). It would be really nice to carry a 90W slim adapter instead of the 170W brick we all complain about.
Don't worry about the power demand, I've never seen my W520 > 30W. And even if for some fairy tale reason you are able to push > 90 W out of a W520, your power supply won't explode, it will just drop voltage, thus making your laptop use the battery.

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Re: W520 requires 170W AC adapter

#109 Post by drewwesley » Wed Oct 31, 2012 7:35 pm

zsero wrote:Don't worry about the power demand, I've never seen my W520 > 30W. And even if for some fairy tale reason you are able to push > 90 W out of a W520, your power supply won't explode, it will just drop voltage, thus making your laptop use the battery.
I'm also getting the similar results without handicaps using Kill-A-Watt to test, but am wondering if those handicaps mentioned (turning off 2 cores, using integrated graphics) will allow the 90W adapter to actually charge (not drain) the battery. Also, does the 90W adapter jack fit the W520? 170W to me seems overkill. I have to carry this thing around every day and am looking to lighten the load. In comparison, I saw a 65W power a T500 and needed a microscope. ;)

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Re: W520 requires 170W AC adapter

#110 Post by zsero » Wed Oct 31, 2012 7:54 pm

drewwesley wrote: I'm also getting the similar results without handicaps using Kill-A-Watt to test, but am wondering if those handicaps mentioned (turning off 2 cores, using integrated graphics) will allow the 90W adapter to actually charge (not drain) the battery. Also, does the 90W adapter jack fit the W520? 170W to me seems overkill. I have to carry this thing around every day and am looking to lighten the load. In comparison, I saw a 65W power a T500 and needed a microscope. ;)
Look, the W520 normally uses around 10-15W. So yes, the 90W adapter will definitely charge it.

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Re: W520 requires 170W AC adapter

#111 Post by drewwesley » Wed Oct 31, 2012 8:20 pm

zsero wrote:Look, the W520 normally uses around 10-15W. So yes, the 90W adapter will definitely charge it.
I couldn't agree more in all practicality/theory, but I think the consensual complaint is that the 90W doesn't charge when in use, likely because of a bios restriction that Lenovo should lift. Have you tested it?

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Re: W520 requires 170W AC adapter

#112 Post by zsero » Wed Oct 31, 2012 8:31 pm

drewwesley wrote:I couldn't agree more in all practicality/theory, but I think the consensual complaint is that the 90W doesn't charge when in use, likely because of a bios restriction that Lenovo should lift. Have you tested it?
That's why you put in the resistor :-) I haven't tried it, because I thought it's easier to buy another 170W and keep it in the place where I'm using my laptop. But the resistor trick is very very easy!

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Re: W520 requires 170W AC adapter

#113 Post by geoffrey » Tue Nov 13, 2012 1:29 pm

In everyday use the W520 is definitely not using anything like 90W. The problem is that the firmware refuses to draw any current at all from a 90W unless the computer is asleep or off. This is why we have to trick the computer into thinking that at least a 135W is connected, and the way to do this is well documented above. The problem is cutting open the tip without destroying it. I destroyed one cheapo tip trying this. The other solution is to swap the cables between a 90W and 170W. Ideally some kind of plug system (one which prevents you reversing the polarity), so that you could use the appropriate adapter for whatever scenario you have.

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Re: W520 requires 170W AC adapter

#114 Post by Kruskal » Sat Dec 29, 2012 2:15 am

This guy is selling Lenovo 170W with NO center pin: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... TQ:US:1123. What do you guys think THAT is all about. I asked the seller and he replied:

> You will have to get that answer from the manufacturer because they made two kinds of them one with pin and one without.
> I am only describing the item as it is.Some machine do not require the centre pin and some does.So check your machine manual
> of the manufacturer website.
> Thanks

If this adapter would actually work, maybe the simplest way to add resistance to a 90W center pin is just to remove it.

Are these tips three conductor -- outside, inside and center?

BTW I bought Chinese knockoff 170W adapters on eBay and they came with standard 20V tips -- not all the extra plastic. Seem to work fine on a W530.

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Re: W520 requires 170W AC adapter

#115 Post by automobus » Sat Dec 29, 2012 12:52 pm

Kruskal wrote:This guy is selling Lenovo 170W with NO center pin. What do you guys think THAT is all about.
Well, let's take a closer look at the item description.
eBay seller breyd25 wrote:Connector : 6.0mm * 3.0mm ; fits Lenovo ThinkPad W700 Series
I think W700 has a different power connector than ThinkPad α60. Now I am even more curious about the 230 watt supply.

And I also think, between the old 5.5mm plug, the W700 6mm plug, and ultracheapsubnotebooks ("netbook") with 2.5od • 0.7id plugs, that leNOvo had even less reason to invent their rectangle connector.

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Re: W520 requires 170W AC adapter

#116 Post by zsero » Sat Dec 29, 2012 1:26 pm

automobus wrote:And I also think, between the old 5.5mm plug, the W700 6mm plug, and ultracheapsubnotebooks ("netbook") with 2.5od • 0.7id plugs, that leNOvo had even less reason to invent their rectangle connector.
They had to invent something rectangular after the new circular keys.

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Re: W520 requires 170W AC adapter

#117 Post by lead_org » Sat Dec 29, 2012 5:53 pm

ThinkPad W70x adapters have no centre pin (and they use a different size barrel shaped connector to the regular Lenovo ThinkPad)
Current ThinkPad: T430u, T430s, X1 Carbon, X1, X230t, X220t, X230, X220, X201t, W520, W701ds, T500, T420 and many more

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Lenovo Slim Power (rectangle connector)

#118 Post by automobus » Mon May 20, 2013 10:48 pm

I found a X1 Carbon and its 90 watt AC Adapter. Its resistance signal is about 550 ohm. Does anybody have a opportunity to check a rectangle 45 or 65 watt supply signal?

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Re: W520 requires 170W AC adapter

#119 Post by automobus » Fri Aug 23, 2013 7:37 pm

I found a UltraRectangle 45W AC adapter. Its resistance signal is about 120 ohm. Does anybody have a opportunity to check a UltraRectangle 65W supply signal?

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Re: W520 requires 170W AC adapter

#120 Post by hellosailor » Sat Aug 24, 2013 4:48 pm

Coming upon this late, and even (sssh!) with a W530...That's some great sleuthing, guys. USB cables use a similar "pull up resistor", what you're calling a signaling resistor, to tell an attached device like a smartphone what kind of cable or accessory or dock it is plugged into. I'd never heard of one in a "simple" power tip before.

But there should also be a simple way to swap power supplies without playing "rocket surgeon" (finally, a situation that justifies the phrase). Just use the one correct tip that you have, and lop offthe power cable about 6" away from the tip. Now reconnect the cable using Anderson PowerPoles or a similar easily-obtained connector, and make the same connection on any powerpack you want to sometimes use with this computer. They'll all plug into the same 6" pigtail that you can leave in your computer all the time, with the right pull-up resistor in it. The advantage to PowerPoles is that you can select colors, and configurations (side by side, or top and bottom, etc.) so that nothing else will plug in and accidentally apply the wrong voltage and polarity.

Unless I find some tips that don't need rocket surgery...I'm going to PowerPoles and it sounds like I should be happily able to use my existing DC-DC adapters and spare AC as well.

If that's been of any help to anyone...Maybe someone could explain to me why Lenovo needs a 20V power supply to charge (in my case) a 10.8 battery, which physically can't take more than about a 13V charging voltage without exploding? In a laptop that also never needs more than 12v to run anything?

I've been asking that question for years, and never heard a logical answer.

--Red
"The only good silicon life form, is a dead silicon life form." [Will Rogers]
-- Harboring a retired T61P with Vista/U/32 and housebreaking a younger W530 foolishly upgraded from Win7/64 to Win10.

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