Lenovo legion y540 adapter pin id

[TheOtherGuy]

So I'm having difficulty finding line drawings for this motherboard NM-C53. My charging port was broken. So I replaced it with a terrible solder job. Problem is pin 3 on the drawing I saw on here has it listed as adapter-id. Now I checked my other pins and I have continuity (resistance check from power to ground). Pin 3 shows nothing. Now I boot the computer and it says to use a power adapter with the proper wattage and won't charge. I have read that pin 3 is usually tied to a resistor that identifies the charging power thus disabled the ability to charge if it fails the check. I look at my board but I don't see any resistors in that area to check to see if I fried it. Any help would be appreciated. It's a 230w charger for clarity.

[mon2]

https://www.reddit.com/r/techsupport...tm_name=iossmf

[TheOtherGuy]

I saw this post about a 4.6k ohm resistance being the proper size. I just was not sure if I should attempt to find that on the motherboard (looked but didn't see any identifiers) or to just pigtail a resistor from pin 3 to ground and cut the pin from the board all together.

[TheOtherGuy]

Also thank you for the response. It's nice to get help when you ask for it.

[mon2]

Remove all power. Meter in resistance mode. Measure the resistance to ground of this center pin on the dc adapter connector.

what is the measurement ?

[TheOtherGuy]

Pin 3 to ground on the computer is open circuit.

[mon2]

Now review your 230W power adapter. Do not have it plugged into the wall. Measure the resistance between the needle like center pin = ADAPTER ID pin & ground which should be the outside large area of metal. That is, the outside surface is often ground.

What is the resistance between these 2 points of interest? It should be ~4k6 ohms.

[TheOtherGuy]

this was from another post i had read from you actually. I see 3 is not connected to anything in this. Thats why i am a little thrown off by this. I'm sorry for coming off like a newbie. If I knew what adapter_id was I could investigate why I have open circuit and maybe make sense of it.

[TheOtherGuy]

Now review your 230W power adapter. Do not have it plugged into the wall. Measure the resistance between the needle like center pin = ADAPTER ID pin & ground which should be the outside large area of metal. That is, the outside surface is often ground.

What is the resistance between these 2 points of interest? It should be ~4k6 ohms.

I have not done this test. Only cause I'm not in front of it at the moment. However the old adapter was broken but functioning. I purchased a new 230 adapter and I believe it works (I should check cause it's always the last place you look) so with two adapters I have the same response. From the computer of low wattage

[mon2]

Certainly test the fuse onboard to see if it is blown. Remove all power. Meter in DIODE mode. Short your meter probes and you should hear a tone beep. Now place the probes across the above referenced fuse. It will tone beep if the fuse is not blown.

Given that the adapter message is being shown on your laptop, very likely the fuse is NOT blown. The fault is with the ID resistor being not detected. In summary, without this resistor, the wrong voltage is being detected by the EC (controller that is used to sense the adapter). This wrong voltage makes the logic board believe the wrong power adapter is connected so the pop up message is displayed.

[TheOtherGuy]

So my power adapter shows 4.6k ohm resistance. So the question is where does the adapter pin jump to on the board. If my board is not making the connection at the location its supposed to then I could check to make sure it's just my inability to make a good connection on the 3rd pin to the board. Then if need be run a wire from the pin on the board to the location it's supposed to go. Or is there an easier way. Used a ton of flux and solder just won't stick to the board (no contact to solder to) please forgive my terrible solder skills. I'm practicing.

[ktmmotocross]

because u dont use flux. did u measure that S fuse?

[mon2]

Suggest to practice on a donor board on the soldering. You are almost there. One the joints you have now, apply flux and more solder onto the joints. Be sure your soldering iron can supply enough heat as these are multilayer circuit boards of 8-12 layers. Respectively, they have massive ground planes drawn with solid copper which can act like heatsinks so your soldering iron tip will cool down upon hitting these joints. For this reason, need a soldering iron setting of higher than normal.

Locate PR229 on the circuit board. Then configure your meter in DIODE mode. Short your meter probe and you should hear a tone beep.

In diode mode setting, connect the RED probe (yes red) to ground on the board (metal shield is ok).

Black meter probe on PR229 pin # 2 - it is the side that also mates to PD203. If in doubt, just test both sides of PR229.

What you are testing here is to check if PD203 (ESD diode) is defective or not. If it is defective, then this line is being pulled LOW - regardless of the outside power adapter resistor of 4k6 ohms.

In a pinch, just flux and remove PD203 off the board for testing. Be patient and use tweezers so the part is not lost and can be placed back onto the board.

[TheOtherGuy]

S fuse is good.

Also my mistake. I thought flux was good to use with a wick to pull solder off the connections then to make good adhesion to the new pin.

Any ideas? I'm lost.

[TheOtherGuy]

Ok so I could not locate pr229. However I did see pd203. So I used resistance and from the pin side of pd203 I went back to the solder area for the adapter pin 3. Located an area there where I had continuity then dragged my solder to that area on pin 3 and voila I have a working laptop again! Thank you mon2 for the words of encouragement as well as the diagnostic steps and drawings. Couldn't have done it without it.

[mon2]

Well done!