Good day,

I have this Hisense 39N2171 that came in for a no power repair. I tried recapping it, but the 12V rail would always give out whenever the TV tries to boot. My best guess is that there is a failing component that somehow knocked the feedback loop right over the edge, but since I don't want to spend any more time on this part, I decided to replace the power supply section with a 12V PSU + backlight driver module. I also replaced all the backlight LEDs as when I tried to test the backlight driver, the backlight was not coming on at all. Now the TV boots and pretty much works...

Re: ideapad 320 14ikb - no power, all rails present

Got it. I'll try programming via usb drive. If that doesn't work, I'll get a usb bios flasher board. Will update if anything works.

Good day! I'm trying to troubleshoot an nm-b242 board. The laptop powers on by default when ac is plugged in. The power button responds and I can turn the laptop off/on, but no display or fan spin. Main rails are present (5valw, 3valw, 1.8valw, vccst, 2.5v_ddr, etc ), even with the laptop turned on. LCD backlight circuit seems ok. The laptop previously had a dead pmic (pu500), which has been replaced and also added pu701 to compensate for the part difference. I'm maybe leaning towards a corrupt bios but I'm not to sure. I'll also add that the fan spins for a seconds then stops. Why could that...

Re: ideapad 320 14ikb (nm-b242) help identifying ic



Thank you! The output voltages are set in the chip, as it seems like there is no feedback resistors for the LDO's. I have yet to see if I can order some in order to fix my laptop. It's kinda a shot in the dark though, as I am uncertain if it will work, or if I have to look elsewhere. Any news on alternative chips to use? I'm not expecting much, because it is exclusive to lenovo. I hope that I still have some chance of reviving it....

Re: List of pin compatible Laptop ICs

any equivalent voltage regulator ic for LV5028AGQV? QFN 5x5 40

The IC in question is an LV5028. It is a voltage regulator ic with multiple outputs, 1v, 1.2v, 1.8v, 2.5v. it powers the ram, pch, and gpu. There is nothing about it on google.
Do you have any sources for similar or substitute ics? If not, do you have a source for donor boards similar to this one? or am I SOL? thanks...

ideapad 320 IKB NM B242 board view

Good day! I am looking for the board view of DG421 DG521 DG721 NM-B242 (ideapad 320) Thanks! The closest things I could find are

[url]http://xn----8sbafotoqlagnhme.xn--p1ai/forums/threads/lcfc-nm-b242-rev-1-0-boardview.16883[/url]
[url]https://************/threads/lenovo-80xh-nm-b241.29823/[/url]

Thank you!https://ideapad 320 IKB NM B242 boar...ew.16883[/url]

Hello! I am asking for a schematic of the ideapad 320 14ikb mainboard, specifically the dg421 dg521 dg722 nm b242 version. I have searched online, but am unable to see one for the kaby lake version. I have no need for the BIOS. Thank you!

Re: New Members - please post your introductions here

Hello! I'm a high school student who is quite into electronics. I've done a few things, such as a lab bench power supply and a guitar pedal, and have repaired an old monitor. I have a few good years of experience just fiddling around with basics. I used to lurk here to read things, but now I'm looking for a schematic for my laptop that has no power. I've done basic troubleshooting, and I've decided that some basic component level repair might be necessary.