Lenovo E555

[medi777]

i have this lenovo thinkpad and i want to connect the charger directly to motherboard.i connected it only the + positive and - negative but it says unknown charger and then shutdown

[JaroTech]

Re: Lenovo E555

Hi, those finicky Lenovo, have you connected the third wire for the adapter identification (ADP_ID)?

[medi777]

Re: Lenovo E555

No the adapter has only 2 wires

[JaroTech]

Re: Lenovo E555

Maybe that's the problem, you need an adapter with the ID wire of the adapter.

[medi777]

Re: Lenovo E555

No the adapter is the original one.i have just cut the end to show the wire

[BlueMidnight]

Re: Lenovo E555

These notebooks have an ID pin, but it doesn't go to a serial chip in the AC adapter like some do (e.g. Dell). Instead, there is a resistor between the ID pin and ground inside the plug. The value of the resistor indicates the wattage of the AC adapter. There is no ID wire needed between the plug and the body of the AC Adapter, and so if you cut open the cable, there will only be 2 wires.

Check out this page for likely resistance value required.

Looks like you probably need at least a 280 ohm resistor between the ID pin and ground to indicate an AC adapter of at least 65W.

[JaroTech]

Re: Lenovo E555

I knew that on the motherboard you have some kind of adapter ID, I did not know it was a resistance in the plug, I'm learning something new every day.

[medi777]

Re: Lenovo E555

I also put the resistance because i found it at thr entry of the charger and still the same

[BlueMidnight]

Re: Lenovo E555

If the resistor is the same value as the one in the plug, and the AC adapter supplies the right voltage, and everything is connected to the correct pins, then the problem must be elsewhere.

I don't have a schematic for that board. But if it is like the other ones, it uses the resistor in the plug as the bottom resistor in a resistor divider between 3V and ground. Measure the voltage on the ID pin and make sure it is not 0V or 3V. it should be somewhere in between.

[medi777]

Re: Lenovo E555

Here how the problem is.the charger port was damaged and also the charger tip.so i cut both of them and want to connect directly.there is no problem with the board.i have done many like this but no one like this lenovo

[medi777]

Re: Lenovo E555

Also the charger has only 2 wire not three

[BlueMidnight]

Re: Lenovo E555

I already explained why the cord has only 2 wires. There is a resistor inside the charger plug (the one you cut off).

The DC jack has 5 pins. 2 are power, 2 are ground, and the middle one is the ID pin. You must attach a resistor between the ID pin and ground. It must be the correct value (280 ohms for a 65W charger, or 550 ohms for a 90W charger).

With the resistor in place, the voltage on the ID pin must be above 0V and below 3V (probably 0.65V with a 280 ohm resistor, or 1.27V with a 550 ohm resistor).

We must know what resistor you used and what voltage you measure on the ID pin. There is nothing else that can be done until you confirm those things.

[medi777]

Re: Lenovo E555

The charger is 40W.i put an 100 ohm resistor and it burned

[BlueMidnight]

Re: Lenovo E555

Hmm 40W is an odd value. I can find 45W and 65W chargers for some E555s, but not 40W. Though there are some 40W chargers for the Yoga series. In any case, there's no way the resistor will burn if connected between the ID pin and ground (unless something is quite wrong with the board). However, it will definitely burn if it somehow gets connected between 19V/20V and ground.

The 5 pins on the DC jack are:
(1) Ground
(2) Power (19V-20V)
(3) ID
(4) Power (19V-20V)
(5) Ground

The resistor goes between pin 3 and ground. Ground can be pin 1 or pin 5 or any other nearby ground point. Before attaching the resistor, there should be 3V on the ID pin. After attaching the resistor, there should be somewhere around 0.4V

[medi777]

Re: Lenovo E555

i put an 200ohm resistor and voltage to pin 3 is 16v

[BlueMidnight]

Re: Lenovo E555

That's not correct. What are the voltages on the 5 DC jack pins without the resistor connected?