Lenovo 320s no power no led

[mon2]

Re: Lenovo 320s no power no led

One input of the dual diode should be the same value as DCIN. The other input to the dual diode is from the battery source. This dual diode performs an "ORing" of the 2 power supplies. That is, either the external power supply OR the battery is used to supply power to the ISL regulator.

For now, just use the external DC adapter and confirm this voltage enters the dual diode. If you do not see the same value on the common cathode pin which mates with the 4R7 resistor then the dual diode is not the "common cathode, dual diode style". The SOT-23 package may look the same but is not the same internally.

You can validate this with a meter in diode mode and check as above post.

[Jeroentje]

Re: Lenovo 320s no power no led

yes the sot has on pin 2 battery power and pin 1 20v dc, pin 3 is only putting battery power out, before resistor 12,05v after 11,8v
I now charge it with adapter in AND power on battery plus, I gues due to the charge chip.

do you have advise for me regarding the q5901 mosfet ?
on adapter power only it does nothing.

[mon2]

Re: Lenovo 320s no power no led

With the battery charged, are you able to power up this computer ?

1) Remove the battery and apply your external adapter voltage (20V?) onto DCIN like normal. Confirm this voltage is reaching pin 1 of the diode @ D5902. If D5902 is working correctly and is a dual diode with common cathode, pin # 3 of D5902 should be a voltage close to DCIN value (0.3 to 0.6 volts lower due to the forward voltage drop of diodes).

What value do you see with only the DCIN mated with an external power supply on pin # 3 of D5902?

This voltage will then go through the 4R7 pair of resistors and continue to power the ISL power supply IC.

If this ISL device is working ok and not burnt out, believe that the Q5901 and Q5902 will then enable to power your logic board.

As you have seen the logic board working already, Q5901 - Q5902 and this ISL components may be working ok. TBD once you confirm the diode.

[Jeroentje]

Re: Lenovo 320s no power no led

On charged battery the laptop will turn on.
1) on pin 1 is 20v on pin3 0,040v, I think I should replcae D5902 first and then check again.

I get get the board on by supply 20v after q5901, not sure if it will charge, the red led is blinking.
on the output of q5901 is 3,6v (all pins)

[Jeroentje]

Re: Lenovo 320s no power no led

ok update

replaced d5902, was a bit smaller, and due to my non expierence some other components moved due to air or movement, but all fixed to it's place. I now also see that the resistors are a bit bigger, I think I need need new glaces haha
therefore always make pictures.
On battery mainboard turns on and windows is loading fine, with ac adpater plugged charge led is white, does not consume a lot power, windows does show charge indication and see a bit v increase (triggle charge ?)
system on at battery and adapter, when remove battery system does turn off
on adapter only no led no power
on D5902 is battery power and adapter power present, at output with adapter is 20v also on resistor (before and after).
after q5901 is 12,4v ( battery ) power present with adapter connected.

[mon2]

Re: Lenovo 320s no power no led

Ok.

1) working with battery only - good

2) with adapter only - does not power on?

3) If not working with the adapter, remove the battery - now the one leg (pin 2) of the dual diode will be zero volts (since the battery is removed). The other ANODE (input pin # 1) to the same dual diode (D5902) will be DCIN voltage @ 20V. Cathode, pin 3 should be close to this value -> enter the 4R7 ohms with a similar value. Please confirm. ISL should then enable the mosfets @ Q5901 and Q5902 (unless they are damaged).

Please share the readings for the locations 1..5

[Jeroentje]

Re: Lenovo 320s no power no led

1) yes!
2) correct
3) yes confirmed (both), 20v, repair is succesfull

pict 1
1) 3.6
pict 2
2. 3,6
3. 3,6
4. have to find it
5. have to find it

[mon2]

Re: Lenovo 320s no power no led

Ok.

1) Check the status line with label AC_PRES. This line should be be HIGH if the external adapter is present and LOW if removed. First monitor the resistor R5914 and one side will be always +3v3 to match the +3v3A_EC rail. The other side of this resistor should be HIGH = +3v3 with the external adapter connected; LOW = 0 volts with the external adapter removed. This is for the ACOK pin on the ISL regulator.

2) According to my voltage divider calculations, the value @ ACIN should be about 2v3.

https://ohmslawcalculator.com/voltag...der-calculator

3) Power down, remove battery and external adapter. Check the resistance of R5912 and R5913. Do the values match the schematic ? This may not be an issue but if the ISL is operating @ 3v3 internally then 3v6 is very borderline dangerous to the IC as a max voltage.

Summary - the ISL detects the presence of the external power adapter (20v) by using a voltage divider to lower this high voltage to a safe value that is acceptable to the ISL component. You are reading 3v6 when the DCIN = 20V. It is a bit high, according to the calculator but may not be an issue. Do post the resistor values for the divider.

Once the ISL detects this external adapter through ACIN pin, the ACOK pin should be logic HIGH = '1' = +3v3 (or close to this value). That is my understanding of this undocumented IC (similar to the ISL9241, etc. which is documented).

[Jeroentje]

Re: Lenovo 320s no power no led

update
regarding point 4 and 5 with the R5904/5
4.9v R5904 4kohm
2.7v R5905 4kohm

1)
Pin 1 2,3v (1,3 without adapter but with battery)
pin 2 0,25v after resistor 0.220 ( seems to turn off ) (3.2v with battery)

3)
350kohm r5912?
45 / 38 kohm r5913

Am I right on the location ?, ohm reading is a bit of wit +/- not stable read

[mon2]

Re: Lenovo 320s no power no led

I am starting to think that U5901 or the front mosfet (Q5901) is defective. On a good note, the controller is in stock (very rare with current market conditions) and available from mainstream distributors:

https://www.digikey.com/en/products/...21AHRZ/6228193

Consider to source a fresh mosfet to replace Q5901:

https://www.aliexpress.com/item/4000...archweb201603_

Part # PK5C8EA (Q5901 replacement) - strong possibility that this is the issue

With the gate @ 4v9 and source @ 2v7 (4v9-2v7 = 2v2), Q5901 should have turned on. The typical ON voltage for Vgs = 1v7.

There may be a cross from ONSEMI or equivalent for this part but have not checked for valid replacements...yet.

For U5901...

Bad part is that the device is a 28 pin DFN which can be tricky to replace. Will need a hot air tool + flux (Amtech NC-559 is good). Suggestion is to source this part and have a (good) cell phone tech replace this for you. Or if you feel comfortable, try it yourself but kapton tape should be placed around the area of this controller so the small parts do not fly off.

[Jeroentje]

Re: Lenovo 320s no power no led

thank you very much for guiding me, i learned a lot.
I have ordered the parts, it will take a couple of weeks but I will place a update here.

nice weekend !

[Jeroentje]

Re: Lenovo 320s no power no led

Hi Mon2

Are you able to provide more info over Q5903, Q5905 and Q5906 ?
How they are connected and what the chip is.

thanks in advance

Jeroen

[Jeroentje]

Re: Lenovo 320s no power no led

ok with schema it is more easy to find the parts, I have done some more measurements. Hope its is readable.
With battery and ac adapter connected btw.

[Jeroentje]

Re: Lenovo 320s no power no led



I replaced the mosfet and the isl. but is does not turn on.
with the mosfet there was no diffrent with the isl you see a short red blink when plug in adapter. so that is new.
but won't turn on with adapter only nor it will charge.
it tries to start but shutdown

[Jeroentje]

Re: Lenovo 320s no power no led

update

I replaced also q5902 because it was shorted, for sure diffrent then the other ones.
Result was no flashing red led anymore while pluging in power cable.
I replaced the isl again with new one, and now the board is fully functional.
So the isl broke (already) or was not good solderd.

Now it does turn on on power only but also charges, all lenovo tests are green/OK.
First succes with real chip replacements.

case closed and @mon2 thank you very much

[mon2]

Re: Lenovo 320s no power no led

Awesome ! Well done