Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

[Funkwarrior]

Hello,
this is my first request of help. I'm an hobbyist without electronic skills, just willing to repair some laptop of friends.

I have a Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev.1.0 without power at all, no led if adapter ac connected. My friend gave me after he broken the pin of the ADAPTER_ID of the cable. I thought I need to change only the part (DC POWERJACK PJ718 DC30100LD00) but after reassembled all the laptop boot fine and entered the OS, but the battery was not revealed . I thought was a software problem: no. The laptop shuts off after 20-30 minutes, even with the ac adapter attached. After few attempts to reboot with power button, the laptop doesn't turn on.
I removed the battery and even with the ac adapter only attached the laptop doesn't turn on (battery discharged? no battery charge from AC?)

I tried to reset bios desoldering and resoldering the battery: nothing changed.

So i'm here to track down what component failed. This is my first time trying to read a schematics but with some help form other posts, I managed to track down these values:

-- All values are readed with no battery, ac adapter in (not original)

JDCIN1 20,3v

PF101 20.3v

PQ301
1 20.3v
2 20.3v
3 20.3v
4 0.5v
5 20.3v
6 20.3v
7 20.3v
8 20.3v

PQ302
1 20.3v
2 20.3v
3 20.3v
4 0.5v
5 20.3v
6 20.3v
7 20.3v
8 20.3v

PU301
5 0v
6 2.6v
16 6.1v
20 20.3v

PQ307
1 0v
2 3.11v
3 0
4 0
5 3.11v
6 0

I hope in some help, thanks!

[caspian]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

all these voltages seem fine. No clue can be found from them. when the laptop does not start, check whether any IC gets hot on the mainboard. It is also possible that it needs discharging, so do what is instructed in the following post:
https://www.badcaps.net/forum/showpo...4&postcount=11

[mcplslg123]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

PQ301/302 Pin4 voltage is not correct. Its gate of the mosfet. You need to look at the schematic why gate is not opening.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Thanks for the replies.
The gates /Pin 4) values need to be 6v?

If you can help me more, it will be a lot appreciated (noob here... )

I attach the schematic (page 53) and the data sheets of mosfets (PQ301 AO4407AL_SO8 - PQ302 SI4483ADY-T1-GE3_SO8)for better help

[mcplslg123]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Check page 53 thoroughly. Fault likely to be within this area. Check PQ304/pr356. If possible, measure voltages for PU301 pins.

Lots of experience memebers are here who can help.

[mcplslg123]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

From the few pins measurements of PU301 you have posted, seems ok as you are getting ACDET/ACOK/REGN/VCC signals which all seems ok to me.

[piernov]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Everything is ok on the charging circuit, nothing to see here.
PQ302 is a P-channel MOSFET so voltage on the gate should be lower than the source for the MOSFET to let the current through, and it's exactly what happening. You're getting 20.3V at point P3. It's a bit on the high side but the system gets powered.
By the way ACOK is active low on bq24737 (and 247x7 in general).
You can still check that you have voltage on B+, PR301 could be blown but I don't think so.

Now refer to the power sequence on page 47, and check what voltage/signal you're missing.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Thank you for all the replies, but this 2 days I'm not at home and with limited connection. I report back as soon as possible. Thank you all again.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

I'm back

...
By the way ACOK is active low on bq24737 (and 247x7 in general).
You can still check that you have voltage on B+, PR301 could be blown but I don't think so.

Now refer to the power sequence on page 47, and check what voltage/signal you're missing.

active low and 247x7 means?

Anyway, seems no voltage on B+ and PR301 (both sides).

Anyway, rechecking the PU301 (somewhere from pin 16 to 20) i think i blow something... smoke from the component (resistor?) highlighted. (maybe PD303?)



Here all the new values for PU301

ACN 1 20.3
ACP 2 2.24
CMPOUT 3 0.02
CMPIN 4 0.02
ACOK 5 11.89
ACDET 6 2.54
IOUT 7 0.01
SDA 8 0.01
SCL 9 0.01
ILIM 10 0.01
BM# 11 0.01
SRN 12 0.12
SRP 13 0.12
GND 14 0.01
LODRV 15 0.01
REGN 16 0.52 to 0.72
BTST 17 0.33 to 0.58
HIDRV 18 0.12
PHASE 19 0.55
VCC 20 2.39 to 2.54

[piernov]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

The values make no sense so check again.
Maybe you're not associating the pin numbers correctly, use the bq24707 datasheet to make sure you understand the pin layout.
The resistor may indeed be blow. According to the schematics, this is PR308, a 10 ohm resistor. Measure the resistance across its leads.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

PR308 seems blowed. I will buy the new components and i will come back.
Thanks!

[Weelcup]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

I think the bq24707 is the cause. Try replace it. The ACN and APN should be the same . Around 20v. Check the condisors connected to acn and apn too.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Hi all, I'm back! Sorry but I'm a bit sick and sometimes I can't going forward as I please.
Anyway, I replaced the PU301 - bq24737 with a bq24735 (link to TI forum support) and the resistor blowned and here's my new values :
1 ACN 20.3
2 ACP 20.3
3 CMSRC 0.1
4 ACDRV 0.1
5 ACOK 0.1
6 ACDET 2.6
7 IOUT 2.3
8 SDA 3.4
9 SCL 3.4
10 ILIM 2.3
11 BATDRV 21.9 to 25.3
12 SRN 20.3
13 SRP 20.3
14 GND 0.1
15 LODRV 0.1
16 REGN 6.1
17 BTST 19.9
18 HIDRV 20.3
19 PHASE 20.3
20 VCC 20.2


Values seems right?
Thanks!

[piernov]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

bq24737 and bq24735 are not compatible. bq24737 has ACOK# active low, bq24735 has ACOK active high.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

really?
I'm so stupid..

[mcplslg123]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

BQ24707A/BQ24727 and BQ24737 are compatible. So you can replace with any of them.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

I tried to refit the first bq24737 i tried to install, as long as I wait for the new one.

The values are correct now? (without battery attached)

1 ACN 20.3
2 ACP 20.3
3 CMSRC 1.3
4 ACDRV 0.3
5 ACOK 0.1
6 ACDET 2.6
7 IOUT 2.3
8 SDA 1.9
9 SCL 1.4
10 ILIM 1.5
11 BATDRV 0.2
12 SRN 19.9
13 SRP 0.1
14 GND 0.1
15 LODRV 0.1
16 REGN 1.7
17 BTST 1.9
18 HIDRV 2
19 PHASE 20.3
20 VCC 20.2

Thanks for the help and patience

[piernov]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Those measurements are a bit strange… Double check that you got the pinout right.

Also check if PQ301, PQ302 or PQ309 is shorted.

[Funkwarrior]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

Thank you @piernov!
I desoldered and resoldered again the BQ and cleaned well the board. The PQ301 legs were a bit dirty.

(I want to apologize for my boring questions and my incompetence... )

Anyways, is the new values:

PU301 - BQ24737

1 ACN 20.3
2 ACP 20.3
3 CMSRC 0.1
4 ACDRV 0.1
5 ACOK 0.1
6 ACDET 0.4
7 IOUT 0
8 SDA 0
9 SCL 0
10 ILIM 0
11 BATDRV 12
12 SRN 20.3
13 SRP 20.2
14 GND 0
15 LODRV 0
16 REGN 1
17 BTST 19.8
18 HIDRV 19.9
19 PHASE 20.3
20 VCC 20.3


PQ301 - AO4407AL

1 S 20.4
2 S 20.3
3 S 20.3
4 G 6.1
5 D 20.3
6 D 20.3
7 D 20.3
8 D 20.3


PQ302 - SI4483ADY

1 S 20.4
2 S 20.3
3 S 20.3
4 G 5.4
5 D 20.3
6 D 20.3
7 D 20.3
8 D 20.3

Thanks!

[piernov]

Re: Lenovo G50-70 ACLU1/ACLu2 NM-A271 Rev. 1.0 no power

It makes even less sense now…
You may not be looking at the right schematics. ACDRV doesn't exist on this board/IC and that's normal because on the charger IC, it's a charge pump that creates a voltage higher than DC in when the DC in MOSFETs are N-channel (their gate would need to be pulled higher than the source which is the DC in voltage).
PQ301 and PQ302 are P-channel MOSFET so their gate needs to be pulled low to turn on, thus ACDRV would be useless.

Also if I trust the measurements of the charger IC (PU301), I conclude that both the charger IC itself and the high-side MOSFET for the battery charging line (PQ309) are bad. But it may be that the charger IC isn't soldered properly.

As for PQ301 and PQ302 I still don't know if they are shorted drain to source. You may check PQ303 too.