Lenovo ideapad 5 windows 11 update disable charging circuit?

[bogart219]

Just got back from the computer shop. The guy was very nice and accommodating but basically didn't want to mess with it. He said, which is probably true, that the time he took troubleshooting it I would be better off getting a another motherboard. I think this place does a lot of board swapping when they can instead of doing SMD work, is the impression I got. I'll just keep F'n with it.
One thing he acknowledge that a windows update can corrupt a up a bios and Sorin said the same thing. I think I'll get one of those CH341A programmers and play with that, nothing to lose at this point.

[m1ch43lzm]

Not the BIOS yet, if it was a corrupted BIOS the laptop would power on, have all voltages but won't show an image (stuck at black screen)
At this point we have to focus on getting the voltages first, why there's no 3.3V and 5V

Yes, it's a bad practice by MS to supply BIOS updates along windows updates, sometimes people are in a hurry and force power off/the update appears to get "stuck", that's usually when BIOS corruption happens in the middle of an update
At least on desktop PCs built from parts that doesn't happen (yet)

For the CH341A additionally you need a WSON8 8x6 adapter, the SOP8 clip that comes usually with those kits won't work here
There's also pogo pin adapters for WSON8 8x6 but you need to hold that for around 2-3 minutes as the CH341A is slow

That computer shop most likely does part replacement or upgrades/cleaning/replacing thermal paste and reinstalling OS/fixing software issues, along selling PCs/accessories, nothing wrong with that of course, but they probably don't do microsoldering
At least they were honest about it

The last resort: find the same laptop but with a broken screen/damaged case or something like that for cheap (but a good motherboard), as I checked ebay and for the asking price of your motherboard you can probably get a used laptop with similar specs...
Just checked https://www.ebay.com/itm/276961397483
a working used/refurbished laptop (exact same model/specs as yours) cheaper than the motherboard for it?



A bit off topic: in my country people will try to fix it going to different shops until the end, sometimes people end in "bad"/dishonest shops that tell you "it's not fixable" but keep the good parts for themselves, then it ends in another shop that tells the truth about the missing parts/beyond economic repair status
Or if the repair cost exceeds the cost of the same item in the used market, it can end in the "scrap"/"for parts" pile of a repair shop

[bogart219]

Ok, I hear what your saying, I'm just Leary about getting used parts but might end up going that route , have to keep looking. It would be nice to find similar laptop with a busted screen for a $100 bucks or something.
This motherboard has two bios chips on it, one is a backup supposdlly so if there was a problem, the board would use or load from the backup I'm assuming. Which one would you even program?

In the mean time:" At this point we have to focus on getting the voltages first, why there's no 3.3V and 5V"
This is exactly what I was thinking.
Being this usb-c charging port only has 5 volts showing because some chip (pd controller) has to "negotiate" with the charger and tell it to let the 20 volts through (still trying to wrap my head around this) its not like in most the video's I see on U-tube where the tech starts with the 19 volts and follows the rails to see where it cuts out, you know what I mean.
Isn't that "negotiating "signal coming from the Pd controller which in our case is the TPS chip? So one of the pins on that TPS chip is sending 3 to 5 volts back to the usb-c charging port to say let the voltage come. Is this correct so far? Will this "negotiating" be in the form of a voltage or a signal? Thats it, where do we start. Its almost like we have to start backwards or something.
So far we know its not the bios and their doesn't appear to be any short circuits, at least the ones that heats up a component. We got 5 volts at the TPS but what path did it take to get there. why can't we find 3.3 volts? so many questions.

[m1ch43lzm]

Most of the motherboards found on ebay are used/pulls, especially the ones from China
Even the prices are too expensive when the same used laptop costs less than the motherboard only (found another used laptop with some scratches/dents at 400), makes no sense to pay more than that for a motherboard...

The BIOS is split between the 2 chips, likely there's a 8MB (has a "64" in the name) chip, and another 16MB (128) chip, I dont know why they split it like that instead of using a single 32MB chip, seems to be done that way starting at 11th-12th Intel CPUs
Before programming you must make a backup of the contents, the board specific data (serial/model/machine type) and the windows key are stored there, flashing a random BIOS will overwrite that info; some shops just don't care about that leaving you with a cloned/empty serial
Or just randomly flash the BIOS without checking the hardware first (why take several hours to troubleshoot a board, when a bios flash can be done in few minutes right? That's what they probably think...)

That's what the people at the bios request sub forum mostly do, they prepare a new bios with your serial, etc extracted from your original bios, starting from a "clean"/"virgin" BIOS

its not like in most the video's I see on U-tube where the tech starts with the 19 volts and follows the rails to see where it cuts out, you know what I mean.

As i said before, that only applies to laptops with a regular DC jack
If only your laptop had a regular DC jack...
I don't think it's a good idea to bypass the whole USB-C input stuff, I haven't tried that

Isn't that "negotiating "signal coming from the Pd controller which in our case is the TPS chip? So one of the pins on that TPS chip is sending 3 to 5 volts back to the usb-c charging port to say let the voltage come. Is this correct so far? Will this "negotiating" be in the form of a voltage or a signal?

Not exactly, the AC adapter starts at 0V output, then it senses through the CC1 and CC2 pins that it's connected to the board and outputs 5V
The communication is done through CC1 and CC2, it's data exchanged through those 2 lines

We got 5 volts at the TPS but what path did it take to get there. why can't we find 3.3 volts? so many questions.

Those 5V you get, are straight from the USB-C ports (which should become 20V)
Don't confuse that voltage, with 5VALW which has to be generated from the main power rail, you don't want 20V on the 5V rail
Even if it's only 5V, that should go after the fuses (and inductors) to the BQ charger input
If you get 5V at the fuses, it's a step in the right direction

Check out the sticky Laptop battery charging circuit
https://www.badcaps.net/forum/troubl...arging-circuit
Yours is NVDC, and it's a buck/boost converter, it has the ability to boost 5V to around 12-13V (main power rail voltage), the input stage is similar to the Macs from around 2016-2017 with USB-C ports, they use different chips but it's the same concept

[bogart219]

Thanks again for the info, I got some studying to do

[bogart219]

Hello again. I haven't given up yet. I'm still looking over this board looking for something thats not quite right. I was focusing on components that looked liked they had a change in color, maybe indicating something going on. Probably nothing but I found a couple of inductors that looked like they got hot maybe.

I measured the inductance of each of these three inductors. I used my zoyi zt-md1 tweezer tester at 10K.
PL5301 - 2.0 SHOULD BE 2.1
PL6501 - .9 SHOULD BE 1.0
PL3001 - .4 SHOULD BE 47 HMM WHY SO LOW? The inductor was measuring 172 ohms to ground as was the 4 caps below it.

Probably nothing.

[m1ch43lzm]

Resistance to GND at PL3001 looks within range at 172ohm, it's the 1.2V supply to the RAM, normal to have that "low" resistance on a low voltage line
The coils look OK to me, the printing looks like it has dissolved/faded a bit with alcohol, they don't look cooked/burnt
Inductance values look OK, within tolerance, consider you're measuring in circuit
R47 means 0.47uH, the R is the decimal point

The 1.2v supply comes after pressing the power button, we're not even at that point, everything goes in sequence

[bogart219]

Ok Mich, I'll keep at it. Thanks for the info on the coils!

[bogart219]

I noticed what looked like rosin oozing out of the CPU at the four corners. anything to be concerned about?

[m1ch43lzm]

I noticed what looked like rosin oozing out of the CPU at the four corners. anything to be concerned about?

That's the black glue/epoxy or whatever Lenovo uses at the factory which makes it hard to desolder BGA chips without damaging the pads on the board

You may have noticed the same glue in the corners of some chips, like the RAM and the EC
Supposedly is to add mechanical strength to those components