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Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sun May 22, 2011 12:43 pm
by volodyan
I have two questions to which I could not find the answers.

1. Why does Lenovo intentionally prevents plugging the 170W adapter to other machines? If they plan to start making the connectors like keys, so that they would not be interchangeable between machines to give Lenovo more profit, it's disgusting. Anyone who understand basic law of physics knows that the argument that "170W is too powerful for other machines" makes no sense - 170W is the maximum rating. In addition, those who bought Mini Dock Series 3 with 90W power supply, cannot use it with the 170W power supply as the connector does not match. Powering w520 in the dock with a 135W adapter would work perfrectly.

2. Why would not they allow topping up the battery of a 90W adapter when the computer is ON? I can see in the Power Manager that W520 consumes about 20W in idle, so it would work normally for light loads even with 65W adapter. The argument that 90W might not be enough also does not make sense: how can getting some power from the wall, even if it is not enough, be worse than just discharging the battery. This is a very important concern for every one who travels with their machine.

Did Lenovo give any explanation?

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sun May 22, 2011 3:42 pm
by davidhbrown
#2. Just one scenario I came up with.... Let's presume that the battery can either be discharging or charging, but not both simultaneously. That makes sense, right? So, maybe you can power the W520 from 65W/90W most of the time, but occasionally something kicks in and the current draw spikes. Suddenly it has to switch from AC power to battery power. Okay, fine let it. But let's say you have different settings in the power manager for AC/battery screen brightness -- as it does by default. Maybe also for WiFi power. USB standby. GPU settings. And maybe the threshold is crossed every couple of seconds (even several times a second).

I could see a situation where a computer was reduced to a beeping, flickering hysterical mess by trying to switch back and forth too often. Yeah, you could "fix" this with a custom power scheme, but the out-of-the-box experience on an Energy-Star-labeled machine could be pretty nasty. (I wonder how the Mac PowerBooks with their 85W power supplies handle this. MikeM, you still here?)

I think there's an similarity to uninterruptible power supplies. Most are "standby" systems where only one power source (battery+inverter or line) is connected to the load. A more expensive "online" (or "double-conversion") always has the load connected to the battery+inverter and available line power can run the inverter and/or charge the battery as appropriate.

If this idea is remotely connected to reality, then perhaps what we need is for Lenovo to come up with a power handling circuit more like the online UPS... but responding to load rather than line.

#1. Could it have anything to do with whatever mechanism is used to sense the current rating of the power supply being incompatible with older machines? I really have no idea. Indeed, it seems like what they needed to do was prevent connecting a too-small adapter, but the plug redesign does not achieve this. But if they really wanted to gouge on adapters, they'd follow Apple's example. (How many different video ports have they come up with over the years? Round serial ports, too.)

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sun May 22, 2011 11:02 pm
by volodyan
#2. I am not an expert, but I do not believe laptop battery is similar to cheap UPS as there is no AC inside of the laptop and according to wikipedia
(http://en.wikipedia.org/wiki/Uninterrup ... wer_supply) the whole idea of standby UPS is to save costs on AC/DC conversion. Besides, they could
force the CPU and GPU into the most power efficient mode instead of just refusing to boot: if I travel with the laptop and intend to use it lightly, why should I lag a 2-pound adapter? Again, for light use it consumes just 20w of power.

#1. The knob in the connector (http://msinetpub.vo.llnwd.net/d1/keithc ... onnect.jpg) has nothing to do with how the laptop senses adapter's power: the connectors of 90W and 130W are identical, yet the computer would not boot with the former if the battery is disconnected.

I have a really strong feeling that they just want to gouge customers on accessories: they want users who already have a 90W Mini Dock Series 3 to buy a 170W version for $200+, while the only difference between the two is the connector. [As well as they would love users to buy more of 130W-170W adapters instead of reusing the old 65W-90W ones, even at cost of inconvenience to the customer]

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon May 23, 2011 9:42 am
by Colonel O'Neill
Anyone willing to shim the connectors? :P

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sat Mar 24, 2012 1:59 pm
by Kaze22
Yes, you can shim the connector. I've done it myself. Works perfect.
The Series 3 Plus docks all have the same board, only difference is the connector.
This is done as a cheap way to force W510 owners to buy new Docks. For a 5 cent connector change, Lenovo makes 250 bucks.
All you need a fine razor, some balls of steal, and a filing unit. Once you shim the teeth down on the 170 AC you're good to go.
Save yourself $250 on a brand new dock.

The only difference between the 135 AC connector and the 170 AC connector is the two protruding keys, file those down and they are the same.

I'm typing a old series 3 dock with a modded connector right now.

Nice forum by the way. I hope my post will save people some money. Spread the word.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Fri Apr 20, 2012 9:18 am
by geoffrey
So can you confirm that if you file away the yellow teeth of the 170W adapter for the W520, you can still use it to run and charge the computer itself (without the dock)? You don't get any nasty messages saying it's the wrong adapter? Also, as well as using it to power the W510 dock for use with the W520. can the filed-down adapter tip also be used to run/charge any other 20V Thinkpad (e.g. a T61) without problems?

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Fri Apr 20, 2012 9:36 am
by Kaze22
Yes, yes and yes.
The filed down 170w works on all Thinkpads and charges lightning fast.
Used it on X301, T61, X220T and etc. Its just plastic man, how is your W520 supposed to know that its gone? Just a little trick used to sell more accessories.
As for using it on series 3 docks, it works on both the 90w and 135w version with no errors. Been using it for a long time now.

The internal board on the 90/135/170 docks are the same Lenovo just changes the connector on the 170w model.

Also if you remove the alignment blocker like I mentioned in my other post, you will
open the dock up for better airflow and X220T support, another cheap trick used to sell you an Ultrabase.

The small tricks Lenovo uses to get you to buy new docks is astounding. Nothing a little logic won't solve.
http://img690.imageshack.us/img690/8803/593f.jpg

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Thu Jun 28, 2012 6:19 pm
by fluffymcdeath
Just wanted to add my 2 cents to this thread. (Actually I only registered to reply to this thread - I don't know Kaze22 though, by coincidence I also live in Vancouver).
I have a W500 sitting next to me that is being powered by the 170Watt brick. As far as power management is concerned it believes it is attached to a 135W supply. Everything works fine.

I used a small x-acto knife to chop away at the tabs. I was wondering how difficult it would be to trim them all the way down the barrel of the connector but it turns out that the outer metal contact wasn't split at the tabs but was a continuous ring and instead the tabs merely lay on top of the metal. Once I had whittled the tabs down to where the outer conductor started they just fell off. I used small needle nosed pliers to get the lose bits out of the hole and now everything is good.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Fri Jun 29, 2012 9:07 am
by stkris
So a 90W car charger for the T61 should also work on my w530 - atleast when it is powered down?

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sun Apr 11, 2021 2:19 pm
by atagunov
stkris wrote:
Fri Jun 29, 2012 9:07 am
So a 90W car charger for the T61 should also work on my w530 - atleast when it is powered down?
You know Thinkpads understand what the wattage of the charger you have plugged in is. There are 3 contacts on the round barrel plug - outer ring, inner ring and the centre pin. Thinkpad measures the resistance between centre pin and outer metal ring. Different chargers have different resistors in their plugs.

65W - 10k
90W - no connection
135W - direct connection (zero ohm)
170W - 1.5k

If in doubt you can check the plug from you 90W car charger with multimeter - you should see that centre pin is not connected.

So once you have plugged that in W530 knows it's a 90W.

So I believe it is totally safe to connect W530 to that charger.
I believe W530 when powered off should still charge its own battery from this 90W car adapter.

When you switch W530 on, I don't know what happens, I have just received my W530, I haven't tried that yet. Will it use both its own battery and external power supply? Will it run but limit CPU to slow speed? Will it refuse to run at all? I don't know. But I know it's safe to try. Just go ahead and see what happens.

====

There is a riskier approach. @wrybread is running his W530 on a 90W wall charger but he is deceiving his W530 into thinking it's a 135W one.

See this topic: https://www.thinkpads.com/forum/viewtop ... 0&p=854470
The actual associated mod is shown very clearly in this post: viewtopic.php?p=856871#p856871

What is going on here? If you insert a jumper as in that photo W530 will think it's got a 135Wt charger connected
135Wt charger has got centre pin connected directly to outer metal contact on the round barrel plug
W530 tests resistance between them and thus learns which charger it is
Different chargers have different resistors fitted
135Wt happens to have a direct connection - zero ohm resistor so to say

So, once you've inserted such a jumper whichever charger at all you plug in W530 will think it is a 135Wt one
@wrybread has written
just used a straight jumper. Commercial Vantage always reports that I have the 135w power adaptor connected, which is apparently acceptable to the W530 gods
My reading of these lines is that when W530 thinks it's got a 135Wt charger it operates normally. E.g. you don't need to give it a 170Wt to make it run at full steam it's enough to give it a 135Wt.

Now once you have inserted this jumper and attached a 90W PSU you have given your W530 permission to draw up to 135Wt out of that charger. What is the danger here? The danger is that you're going may possibly overload the charger. The charger may break down. The charger may overheat and catch fire. The charger may just refuse to work and stop supplying voltage. The charger may start delivering lower voltage. I don't know if that is dangerous for W530 to be supplied lower voltage.

To increase your chances of not overloading the charger you can do a couple of things

- avoid loading the GPU; just don't run 3d loads; if you want to be 100% sure you can go to BIOS and switch graphics to "Integrated"; then nVidia GPU will definitely not get engaged

- not engaging nVidia should probably be sufficient to lower the power under 90W, but you can also inhibit battery charging; I'm a Linux person; I think I know how to do it under Linux; but there should be a way to do it under Windows too

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Apr 12, 2021 6:25 am
by axur-delmeria
atagunov wrote:
Sun Apr 11, 2021 2:19 pm
You know Thinkpads understand what the wattage of the charger you have plugged in is. There are 3 contacts on the round barrel plug - outer ring, inner ring and the centre pin. Thinkpad measures the resistance between centre pin and outer metal ring. Different chargers have different resistors in their plugs.

65W - 10k
90W - no connection
135W - direct connection (zero ohm)
170W - 1.5k

If in doubt you can check the plug from you 90W car charger with multimeter - you should see that centre pin is not connected.
Dude, why are you replying to a 9-year old thread? :o

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Apr 12, 2021 6:50 am
by unixed
He started his reply 9 years ago but was using an under-powered AC adapter.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Apr 12, 2021 7:07 am
by Shredder11
I often reply to old topics / threads too, usually because I am preoccupied with the question and answer, that I do not see the post date.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Apr 12, 2021 7:32 am
by atagunov
axur-delmeria wrote:
Mon Apr 12, 2021 6:25 am
Dude, why are you replying to a 9-year old thread? :o
Yeah, my bad. Was probably too tired and picked a thread from the bottom of the screen under another topic.
I can swear I thought it came up in "Active topics" list, but I probably looked at wrong part of the screen.

Sorry

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Apr 12, 2021 8:32 am
by axur-delmeria
unixed wrote:
Mon Apr 12, 2021 6:50 am
He started his reply 9 years ago but was using an under-powered AC adapter.
That's a good one! :lol:

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Fri Jul 23, 2021 8:13 pm
by wsalomon
I'm about to deal with this as my 170 w supply is about to lose its plug from bending next to the plug boot.

I've read about 2 outer barrel contacts (to clue the motherboard as to what is attached) but mine certainly does not have that, nor does the power jack have that.

I've read about the resistor in the plug (will measure that if it needs to be cut off, or if it has one in adjacent ferrite RFI suppressor).

Which leads to... if I need to source a plug alone (and the same goes for a 90 w supply without the two yellow tabs), is there any source other than finding a dead supply with a "viable" cord and carefully splicing and using shrinkable tubing to replace it (or getting one from a cheapie "knock-off" and using that). (I've never seen a replacement plug alone, and have looked for them - I would have figured I might have found one for to 90 w supply which is far more common than the 170 w).

Any thoughts?

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sat Jul 24, 2021 1:21 pm
by atagunov
wsalomon wrote:
Fri Jul 23, 2021 8:13 pm
I'm about to deal with this as my 170 w supply is about to lose its plug from bending next to the plug boot.
Ouch, not good
wsalomon wrote:
Fri Jul 23, 2021 8:13 pm
I've read about 2 outer barrel contacts (to clue the motherboard as to what is attached) but mine certainly does not have that, nor does the power jack have that.

I've read about the resistor in the plug (will measure that if it needs to be cut off, or if it has one in adjacent ferrite RFI suppressor).
Hmm.. it sounds like you might be confused.. Does the image on this page help? http://forum.notebookreview.com/threads ... es.681124/

That page says - and the numbers are correct for round plugs only, square plugs have different resistors:
65W adapters have 10K resistance
90W adapters have no connection
170W adapter has 1.5K resistance
There is also 135W - direct connection I think
wsalomon wrote:
Fri Jul 23, 2021 8:13 pm
Which leads to... if I need to source a plug alone (and the same goes for a 90 w supply without the two yellow tabs), is there any source
other than finding a dead supply with a "viable" cord and carefully splicing and using shrinkable tubing to replace it
That is a very valid question you're asking. I am personally not aware of a source for plugs apart from old power supply units.

Do I understand correctly that your wire is damaged very close to Thinkpad? And you would like to replace the plug on your 170W PSU? That would be sensible but I really don't know where to get a new one...

One crazy idea I had was: take the plug - with a section of the wire - from any Lenovo PSU at all and physically remove the central pin. I'm not sure how to do it.. But there might be a way.. Heat it up with soldering gun and pull out with pliers? Don't know.. But if you could remove the central pin Thinkpad would start thinking it's got a 135W PSU. Somebody wrote on this forum a W520 or W530 - don't remember which one - actually ran fine on a proper 135W PSU.. One minor concern here is that if you take the plug and section of the wire from a 60W PSU the wire could potentially be quite thin and so prone to getting warm. To counter that it's probably advisable to take a small section of wire from donor PSU. I'm not actually sure if Lenovo has been using thinner wire on 60W units than on 170W units.

Update: that was a stupid idea. Removing central pin would make it "unconnected" e.g. signifying 90W adapter. To signify 135W you'd need to connect the pin to outer circular contact directly. Another idea I had was to take a regular 65W plug, put it into vice and drill a hole so that the lead to central pin would be exposed. But it would be a lot of trouble and I never tried.

Another option is to hack it inside the Thinkpad. Disconnect that central pin wire from PSU completely and do what you like with it: leave unconnected to make Thikpad think every adapter is 90W, make a direct connection making thinkpad think every adapter is 135W or even put in a 1.5K resistor to make it think every adapter is 170W. It will work but the consequence will be that if you accidentally plug in an adapter of too low wattage Thinkpad may overaload it.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Tue Aug 10, 2021 5:10 pm
by cadillacmike68
I just said screw it and bought 2 extra 170W AC adapters. They stay with the series 3 docks and the original 170W goes where the W530 goes.

And I shaved off the protrusions inside all the connectors so they can all fit the T530 and all the T61s & W500s.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Wed Feb 01, 2023 9:02 pm
by deickos
Though the topic is old the question is still in demand.
I too was wondering if one could turn on w520 using the 90w adapter - many 135/ 170w sellers will tell you no to get your money. Running with intel graphics makes it possible.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Fri Feb 03, 2023 12:32 pm
by elka.
A manufacturer would not want to bother suporting 90W adapter for partial functionality when they can just sell the 170W adapter. Testing & support cost would be large for no benefit to the manufacturer, as every new laptop would be sold with the 170W adapter.

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Sat Feb 25, 2023 8:37 pm
by jcvjcvjcvjcv
https://www.thinkwiki.org/wiki/Power_Co ... her_Models

(I didn't put it in the wiki)
deickos wrote:
Wed Feb 01, 2023 9:02 pm
Though the topic is old the question is still in demand.
I too was wondering if one could turn on w520 using the 90w adapter - many 135/ 170w sellers will tell you no to get your money. Running with intel graphics makes it possible.
You mean with the nVidia disabled in BIOS? And then it actually runs off the 90W?

Re: Incompatibility by design: 170W vs 135W vs 90W. Why?

Posted: Mon Mar 06, 2023 11:20 am
by deickos
jcvjcvjcvjcv wrote:
Sat Feb 25, 2023 8:37 pm
https://www.thinkwiki.org/wiki/Power_Co ... her_Models

(I didn't put it in the wiki)
deickos wrote:
Wed Feb 01, 2023 9:02 pm
Though the topic is old the question is still in demand.
I too was wondering if one could turn on w520 using the 90w adapter - many 135/ 170w sellers will tell you no to get your money. Running with intel graphics makes it possible.
You mean with the nVidia disabled in BIOS? And then it actually runs off the 90W?
yea but of course the cpu will throttle with the 90w - only partial functionality