Lenovo ideapad 5 windows 11 update disable charging circuit?

[bogart219]

I got to have something touching somewhere , where its not supposed to touch by getting that flashing OL reading on my meter where I should be reading 3 and 5 volts. I started looking for solder blobs again. I was checking the components that I put down and found that TPS chip I replaced , I was actually able to push it around with my tweezers1, wtf, It wasn't soldered down properly.a cap right next to it came off too! Let me get this straighten out (hopefully). Also hoping this was the cause of the flashing readings! I will let you know! Thanks!

[bogart219]

You're missing both +3VALW and +5VALW, those are very important, if those are missing the power on sequence stops there
Measure +3VALW_EN on PC6230 (may be missing from the board, that's ok)
and +5VALW_EN on PC6231 (may be missing from the board)

Those should be high level, 3.3V, if they're 0v something went wrong
I've marked the location where you can measure those signals, in green for +5VALW_EN and yellow for +3VALW_EN

PC6230 = 3.28 VOLTS
PC6231 = CAN'T FIND (MISSING) ?

[m1ch43lzm]

PC6231 is also a missing component, but the solder pads are there, go back to post #131 on the previous page, the pictures are back , I marked it with a green line
Ok, now the 3.3v are enabled, you should get now 3VALW

[bogart219]

Try setting your multimeter to volts, manual range appropriate for 3v, if it's auto range
If manual range set to 20v range

Just want to confirm if that chip is being told to enable the 3VALW and 5VALW outputs by the EC IT8227 (it's branded "Lenovo", a BGA chip which may have black glue on the corners, it it has the glue better not to try to remove it, as the pads on the PCB may become damaged)
Inspect the area first for stray solder blobs

Expected steady 3.3v on those enable signals
Also check RE4501 and RE4505, should be 0 ohm resistors, or may be just traces, those feed 3VL to the EC


Pictures were lost , hopefully the admin will fix the forum issues

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I remember part of your follow-up question before the post was gone, it was about where the 5v goes
The 5v should go after the MOSFETs, on the fuses, even if the TPS65994 hadn't negotiated the 20v yet, it should pass those 5v to the BQ

It's a bit complicated, because the sequence I think is like this:

Charger only, or a completely empty battery
1. The TPS65994 passes the 5v to the BQ, which will boost those 5v to 13v (if battery is not present), creating the main power rail
2. The RT6585C (PU6219) generates the 3VL and 5VL by internal LDO regulators, from the main power rail
3. The EC (embedded controller) IT8227 (UE1) powered by 3VL, then tells the RT6585C to enable the 3VALW and 5VALW outputs
4. The EC also communicates with the TPS65994, feeding it the required firmware
5. then the TPS65994 negotiates the 20v
6. After getting the 20v, the BQ charger IC acts as a buck converter, generating the appropriate voltage for charging the battery/main power rail
7. We're in S5 power state, the EC waits for the power button press to turn on the laptop
Some laptops will also power on on their own if the RTC battery is not present or was unplugged before

With a working battery step 1 changes to:
1. The BQ connects the battery to the main power rail through a MOSFET
Skip 5 and 6 if charger not plugged in

Hopefully what I wrote is understandable, or maybe too technical?

Further reading: https://www.badcaps.net/forum/troubl...arging-circuit
Yours is Narrow VDC (NVDC) topology, buck-boost converter

The issues your laptop has right now are separate, if now we're not getting those voltages (3VALW, 5VALW), either due to a short, or it's not being told to enable, that's what I want to check first
Before you removed the MOSFETs it powered on from battery, so maybe a stray solder blob, or missing resistor that got dislodged somewhere

Reflowed the TPS chip and reattached the cap, still getting flashing meter like before.
With batt & charger plugged in. On the BG chip, ( PU5301) was getting 11.7, 3.2 and 1.4 volts on a number of pins. RE4501 & RE4505 , NOT ON THE BOARD.

[bogart219]

PC6231 is also a missing component, but the solder pads are there, go back to post #131 on the previous page, the pictures are back , I marked it with a green line
Ok, now the 3.3v are enabled, you should get now 3VALW

Pics still not working for me. Will try again in the morning, thanks.

[m1ch43lzm]

Reflowed the TPS chip and reattached the cap, still getting flashing meter like before.
With batt & charger plugged in. On the BG chip, ( PU5301) was getting 11.7, 3.2 and 1.4 volts on a number of pins. RE4501 & RE4505 , NOT ON THE BOARD.

11.7 is from the battery, that chip is doing its job for now

Check again
+3VALW at PJ6201
+5VALW at PJ6206

May need to scratch a bit those points with the probes, sometimes flux from manufacturing can form a non conductive layer over the solder blobs

The enable for 3VALW is present, so we should have 3.3v there with just the battery connected

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Sorry for the pictures not showing, only noticed the thumbnails working now, but the full image doesn't work

The admin is working on fixing the attachments, we have to wait

[bogart219]

11.7 is from the battery, that chip is doing its job for now

Check again
+3VALW at PJ6201
+5VALW at PJ6206

May need to scratch a bit those points with the probes, sometimes flux from manufacturing can form a non conductive layer over the solder blobs

The enable for 3VALW is present, so we should have 3.3v there with just the battery connected

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Sorry for the pictures not showing, only noticed the thumbnails working now, but the full image doesn't work

The admin is working on fixing the attachments, we have to wait

Hi. when I check the voltages to ground on PJ6201 and PJ6206 with just the battery, the meter just flashes back and forth between 1 and 3 volts approx. No steady reading.

[m1ch43lzm]

That could mean there's an issue with either 3VALW or 5VALW, can also be related to the flickering on the USB-C meter

Try removing the solder blob at PJ6206, add fresh solder then use solder wick to clear it

With only the battery, Repeat the measurements at PJ6201, and either side of PJ6206, check if the 3.3v and 5v are stable now (laptop won't power on for now)