Did my homework on the Lenovo SlimTip charger port. In my case if I am using a single DC-DC power supply to power up the MB than a 4.6kohm resistor should be used to ground on the PJ1 connector of DC-in, pin 9. See the following link: [url]https://www.thinkwiki.org/wiki/Power_Connector#230W_11.5_Amps[/url]. Khaahk is right, this pin should be at right resistance concerning the MB type. The pin9 is named ACDC_IN which goes to the Thinkengine EC ADC input. This input is pulled up to VCC3M. It means this voltage should be present to be able to identify the connected charger. As far as I remember...

OK, you have a point. I use a DC-DC converter for the test with an external SMPS. I thought the extra pin in the Lenovo power adapter is used only for charging purpose but it could be possible Thinkengine monitors this signal presence and if not present disables the main power rail immediately. I tried with a Lenovo 135W adapter as well with the same result therefore I thought the extra pin emulation is not important in my case.. Anyway it worth a try.

One more thing I do not know. How the MB is reacting when it gets power from the adapter, with no battery? Is it try to start or...

Thank you your reply. The main power rail is down, not swtching on as described above. The maximum current is 100mA in this state of the MB. Only the Thinkengine ICs got the 19V, no other subsystems are powered, all the V rails are 0V, except V3SWT generated by the Thinkengine IC. The usage of smaller than 170-210W adapter could cause problem when the systemis starting up or under heavy load but unfortunately not inmy case. Wish I would be there.

I was able to move forward because bought the schematics and got the boardview file from the forum.

I replaced the 330uF tantalum capacitors on the VCCGFXCORE_D rail. Soldered back the coils as well.

The situation became worst: no power at all, not for one second. I have attached the schematic of the DC-IN section to better understand the "strange" situation.
Symptom: there is no voltage at the output of the PQ1 P-channel mosfet because its gate always on DCIN_PWR20_F, ie. at 19V. It seems the Thinkengine switches off the MB immediately with PWRSHUTDOWN...

Hi,

Try to repair a Thinkpad P72 EP720 NM-B723 MB with I7-8850H processor and N18E-Q1-KB-A1 (P3200) GPU with 6GB memory. Unfortunately there is noinfo what happened to the laptop. I got it disassembled with parts missing, like keyboard, battery.

Unfortunately I have no schematic available for me (requested in the sub porum) but got the boardview file.

Symptom: after connecting to the charger the power led light up for one-two second and switch off. After a couple secons the power led light up for half a second and switch off. No battery, no IO board, no...

Thank you your reply, it is a big help indeed. Still waiting for the shematic, maybe someone has it and willing to share....

Sorry I missed it the right type is EP720 NM-B723 as you wrote. Thank you for the correction....

Hi,
If you have schematics, boardview for the EP720 NM-723 Thinkpad MB with N18E-Q1 GPU than please help me to be able to repair one. Thank you in advance!

Hi,

I try to repair an iphone SE 2022 model but I was not able to find a schematic and boardview for that. Unfortunately Phoneboard has a version 1 SE only, ZXW is not an option for me. If you have access for these please share with me.

Thank you!

Hi Blaze Tech,

I started the investigation of the board for a while. Unfortunately I ran into a problem: it seems the provided schematics/brdview files are for the Surface book 1 version 1703. I am a unfortunate one having the 1704 version, PCB PN is X938453-005. The 1703 schematics are useable but there ar a lot of changes especially in the voltage regulation parts: 1704 version uses less number of parts using updated, more complex gate driver ics from TI.

Is there any canche to have a 1704 version of files in your reach? If yes than can you share with me? Do you have...

You are the man, thank you very much your quick respone!

Hi,

My wife loved suface book 1 needs to be repaired and I am looking for schematics and boardview data in order to try to attempt the repair of not charging the upper battery, If you have it please share with me, thank you in advance.​

Hi,

I am looking for a place to share and-or look for information regarding HW repair DIY projects on computer filed. My main interest area where I have some experience in repair:
- retro PCs - 386-486 based processors, MB repairs
- retro calculators like TI brand repairs.
- laptop repairs
- mobile phone repairs, Samsung S7, iphone 7,8

If you have questions regarding these areas feel free to ask for help....