Lenovo ideapad 5 windows 11 update disable charging circuit?

[bogart219]

A fuse should read 0 ohms, so both fuses got blown if you're measuring resistance across them
Measure resistance to GND after the fuses, if not shorted (tens of K upwards) then the fuses may have gotten damaged due to heat

The flashing on the USB-C tester may indicate a fault with the TPS65994 or related circuit, sometimes ICs can get damaged when heat is applied for long time

You can start by measuring resistance to GND on the power pins of TPS65994, VIN_3V3_PD1 at CU207, VCC3_LDO_PD1 at CU209, or at the left side of RPU203, VCC1V5_LDO_PD at CU208, and 5VALW

mon2 what do you think?

Hey M1c, thanks for sticking with me. When i was heating those components, I put caption tape all around the component I was heating. That doesn't mean something still didn't get damaged by the heat.
Measuring the persistence to ground after the fuses, both read 1.2 meg. This means the fuses are blown, correct?

VIN_3V3_PD1 at CU207 = 1 MEG AND FALLING, LIKE ITS DISCHARGING.

VCC3_LDO_PD1 at CU209 = 1 MEG AND FALLING, LIKE ITS DISCHARGING.

RPU203 = 1 MEG AND FALLING, LIKE ITS DISCHARGING.

VCC1V5_LDO_PD at CU208 = 20 MEG

The 5VALW PINS 11,12 & 25,26 ON TPS65994 = NOTHING TO GROUND.

[bogart219]

Well I found the reason I believe that my usb-c tester was flashing when plugged in. It was a solder bridge from that cap I took out (PC5302). Once I cleaned that up, my usb-c tester was no longer flashing and back to 5 volts again. Now to find out what the other problem is.
Question, it appears that one fuse is bad . How would I look that up on Digikey? 5 amp 32 volt ceramic fuse? Also while I'm at it, get some some ceramic caps. 10 ohm 25 volt ones. What do you think? Thanks!

[m1ch43lzm]

https://www.digikey.com/en/products/...600M-2/8681948
Both fuses are suspect, you shouldn't have 15K across the fuse, they should be 0 ohm

Your fuses are marked "O", I think this one is an exact match, 6A 0603 fast acting fuse, the fuse markings vary between manufacturers which makes it even more confusing

But we know the rating on the charger, if your laptop specifies up to 100W charger, that is 20V*5A, the 5A fuse will be barely suitable, the 6A fuse has a little headroom to not blow during normal use
Sometimes components get changed on the final production version compared to the schematics

for the caps, "10uF 25V 0603 X5R" is what you should look for
https://www.digikey.com/en/products/...A8NRNC/3887527
There's a discount if you order 10 of more

[bogart219]

https://www.digikey.com/en/products/...600M-2/8681948
Both fuses are suspect, you shouldn't have 15K across the fuse, they should be 0 ohm

Your fuses are marked "O", I think this one is an exact match, 6A 0603 fast acting fuse, the fuse markings vary between manufacturers which makes it even more confusing

But we know the rating on the charger, if your laptop specifies up to 100W charger, that is 20V*5A, the 5A fuse will be barely suitable, the 6A fuse has a little headroom to not blow during normal use
Sometimes components get changed on the final production version compared to the schematics

for the caps, "10uF 25V 0603 X5R" is what you should look for
https://www.digikey.com/en/products/...A8NRNC/3887527
There's a discount if you order 10 of more

Thank You my man, I'm going to get those ordered right away! Thank you!!!!!!!!!!!!!

[m1ch43lzm]

If you don't have already, consider ordering some 27AWG 63/37 solder wire
It's easier to work with 63/37 lead/tin solder compared to lead free

[bogart219]

If you don't have already, consider ordering some 27AWG 63/37 solder wire
It's easier to work with 63/37 lead/tin solder compared to lead free

M1c,I'm glad you mentioned that. I have some solder that I've had for years. Would this one from radio shack be any good to use?



I got two 1 lb. spools of this solder that will last me for ever. I used this solder on thru hole work, which seemed to work good.



What do you think? If you think I should get something different I will.

[m1ch43lzm]

Sn62Pb36Ag2 should be fine as the melting point is 179 C (354 F), if what you already have is thin gauge (0.015") like the pictures it's OK to use
EDIT: Just noticed you wrote 0.022", it may work too, thinner gauge is easier for small components
Sn63Pb37 is more common, with a melting point of 183 C (361 F)
Those two types solidify quick, Sn60Pb40 stays molten for a while

The lead free stuff starts at 217 C (423 F) upwards, so it's good practice to replace with Sn63Pb37 (or Sn62Pb36Ag2 if you have it) when doing repairs, as manufacturers have to adhere to RoHS directives which restrict the use of leaded solder

Reference https://www.kester.com/knowledge-bas...perature-chart

[bogart219]

Sn62Pb36Ag2 should be fine as the melting point is 179 C (354 F), if what you already have is thin gauge (0.015") like the pictures it's OK to use
EDIT: Just noticed you wrote 0.022", it may work too, thinner gauge is easier for small components
Sn63Pb37 is more common, with a melting point of 183 C (361 F)
Those two types solidify quick, Sn60Pb40 stays molten for a while

The lead free stuff starts at 217 C (423 F) upwards, so it's good practice to replace with Sn63Pb37 (or Sn62Pb36Ag2 if you have it) when doing repairs, as manufacturers have to adhere to RoHS directives which restrict the use of leaded solder

Reference https://www.kester.com/knowledge-bas...perature-chart

Great, thanks.

[bogart219]

Thank Mods for getting this post back up. I got the parts in and installed I'm ready to continue my quest. Now where was I?

[bogart219]

When I started out trouble shooting this board here, with the battery plugged in I was getting 20 volts on my usb-c tester. Now I only get 5.2 volts with or without the battery plugged in. Do you think it would be a good time for some voltage injection and scan with the thermal camera?

[m1ch43lzm]

Does the laptop power on from battery only?

[bogart219]

Does the laptop power on from battery only?

NO