Lenovo Thinkpad charger with magsafe 2 cord?

[swimllamaswim]

My magsafe 2 charger broke, the cable frayed and the pad ripped off while trying to desolder the cord from it. So I looked up the specs of a magsafe 2 charger and saw that it matches up with Lenovo thinkpad chargers (the old style, with the barrel connector). If I spliced the magsafe 2 cable onto it, would that work? The only difference I've seen is that the thinkpad charger is 90w instead of 85w like the magsafe charger. Am I completely off base here?

[linux-works]

thinkpads have a 3 connector jack.  there's a programing resistor there that the laptop senses.

research that, first.

[Monkeh]

In a word, no, you can't just patch the cables together and go.

E: well, maybe. But.. don't. Just get the right charger or fix your soldering job.

[swimllamaswim]

thinkpads have a 3 connector jack.  there's a programing resistor there that the laptop senses.

research that, first.

Oh I know but it still has two wires in the cord, just like the magsafe charger. I have about a hundred of these Thinkpad chargers so I took one apart.

[helius]

Oh I know but it still has two wires in the cord, just like the magsafe charger. I have about a hundred of these Thinkpad chargers so I took one apart.

See http://www.righto.com/2015/11/macbook-charger-teardown-surprising.html
The Apple charger's cord has 4 wires (+, -, enable, and ground), not 2.

[Monkeh]

Oh I know but it still has two wires in the cord, just like the magsafe charger. I have about a hundred of these Thinkpad chargers so I took one apart.

See http://www.righto.com/2015/11/macbook-charger-teardown-surprising.html
The Apple charger's cord has 4 wires (+, -, enable, and ground), not 2.

Err, where are you seeing those magical extra conductors?

[RGB255_0_0]

Looking at this https://www.ifixit.com/Guide/MacBook+Power+Cord+5-Pin+MagSafe+Connector+and+Cable+Replacement/21842 I don't see why any (correct) wattage power supply wouldn't work since the MagSafe connector has all the goodies inside such as the chip that talks to the SMC.

[CJay]

thinkpads have a 3 connector jack.  there's a programing resistor there that the laptop senses.

research that, first.

Umm, no, they really don;t use a resistor to 'program' anything.

What they do have is an electronic ID chip that's connected to the central 'needle' pin in the barrel connector.

The system communicates with that chip to identify the charger type and allow the BIOS to verify the charger capabilities and that it's a genuine part.

For once Apple were behind the curve when it comes to ripping off customers as that scheme has been used for years by Dell, HP, Lenovo and no doubt others too.

[Monkeh]

thinkpads have a 3 connector jack.  there's a programing resistor there that the laptop senses.

research that, first.

Umm, no, they really don;t use a resistor to 'program' anything.

What they do have is an electronic ID chip that's connected to the central 'needle' pin in the barrel connector.

http://www.thinkwiki.org/wiki/Power_Connector#Signal_Pin
http://www.thinkwiki.org/wiki/Power_Connector#Signal_Pin_2

[CJay]

thinkpads have a 3 connector jack.  there's a programing resistor there that the laptop senses.

research that, first.

Umm, no, they really don;t use a resistor to 'program' anything.

What they do have is an electronic ID chip that's connected to the central 'needle' pin in the barrel connector.

http://www.thinkwiki.org/wiki/Power_Connector#Signal_Pin
http://www.thinkwiki.org/wiki/Power_Connector#Signal_Pin_2

*hangs head in shame*

I take it back, I had been wrongly informed that Lenovo used the same or similar scheme to Dell and HP

[Monkeh]

*hangs head in shame*

I take it back, I had been wrongly informed that Lenovo used the same or similar scheme to Dell and HP

Only in that they restrict performance or charging based on the connected adapter. Some people take that as a great injustice and a ploy to prevent the use of third party chargers.

Those people are idiots.

[LA7SJA]

This is one of the best explanations of how the "magic" Apple charger circuit works:



Johan-Fredrik