Lenovo Y50-70 Completely dead, no lights at all.

[didutgendut]

Hello.
I have a laptop for repair that probably dead.
Has no response at all, neither battery charging, neither on pressing power on, no led lights up.
the ac adapter is all fine i still can get 20v in the input section and all fuses in the input is still good(id pin is good)
when i do a short findings, i find that there is short between PQ302 pin 5-8 and the ground. is it alright ? would you please help me what i have to do next to check?
Schematics of M/B uploaded.
Thanks in advance !!!

[s.m.hosein]

Re: Lenovo Y50-70 Completely dead, no lights at all.

took of the ram and test again
first check the 3.3 voltage on power switch and i/o and bios ic
if you had that voltage try programming i/o and bios because its very common on this model
but if you have not the voltage then you should start testing the board on schematic

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

there's no voltage at all on the board. would you please tell me how should i start test the board

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

took of the ram and test again
first check the 3.3 voltage on power switch and i/o and bios ic
if you had that voltage try programming i/o and bios because its very common on this model
but if you have not the voltage then you should start testing the board on schematic

there's no voltage at all on the board. would you please tell me how should i start test the board

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

That's mean you have shorted at 20V line (B+for all system)
-Did you have bench PSU?
This tool would help you for finding shorted on mobo
-If you didn't have one, try to isolated 20V (B+) from other circuit with opened the jumpers (PJ3xx, PJ4xx, PJ5xx) that connected to B+.
-If you open PJ301, you have isolated High side Mosfet at block charger from B+ (first main line=PR301). then measure on pin5-8 PQ302 respect to gnd. do you get value of short or not?
-If short still remains, Do open PJ401 (block 3V circuit) then measure again on pin5-8 PQ302 respect to gnd. you get short or not. shorted still in there, do open for other jumper. like step above. if short has gone, where you last open a jumper then that block have component was fault, may be caps ceramic.
-Be carefull, many IC PWM that have high side and low side mosfet in one package QFN like PU401 in example.
-Also would be help if you measure resistance on all coils / inductors.
in example if you have shorted 3V at output, PU401 has shorted internally between input and output, can cause B+ like shorted too, (multi shorted)

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

That's mean you have shorted at 20V line (B+for all system)
-Did you have bench PSU?
This tool would help you for finding shorted on mobo
-If you didn't have one, try to isolated 20V (B+) from other circuit with opened the jumpers (PJ3xx, PJ4xx, PJ5xx) that connected to B+.
-If you open PJ301, you have isolated High side Mosfet at block charger from B+ (first main line=PR301). then measure on pin5-8 PQ302 respect to gnd. do you get value of short or not?
-If short still remains, Do open PJ401 (block 3V circuit) then measure again on pin5-8 PQ302 respect to gnd. you get short or not. shorted still in there, do open for other jumper. like step above. if short has gone, where you last open a jumper then that block have component was fault, may be caps ceramic.
-Be carefull, many IC PWM that have high side and low side mosfet in one package QFN like PU401 in example.
-Also would be help if you measure resistance on all coils / inductors.
in example if you have shorted 3V at output, PU401 has shorted internally between input and output, can cause B+ like shorted too, (multi shorted)

Yes, i have bench PSU. Should i keep following instructions you just mentioned or use another method with the bench psu? Because i cant find PJ301.

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Yes, i have bench PSU. Should i keep following instructions you just mentioned or use another method with the bench psu? Because i cant find PJ301.

Definitely I refer wrong schematic, since you've mentioned problems on other thread. https://www.badcaps.net/forum/showth...t=56200&page=2
Is this first time experience with shorted B+?

I think I knew correct schematic for this case, it's LA-B111P, right?
1. LA-B111P, B+ connected to other component like IC PWM and High Side mosfet through PL wasn't Jumper pad (1UH +-20% PH041H-1R0MS 3.8A / HCB2012KF-121T50_0805 / FBMA-L11-201209-121LMA50T_0805) the shape like ceramic capacitor, but have more dark color. So be carefull, don't think it was capacitor.
2. provide of your resistance measurement on all big coils.
3. Would Prefer identifying and make list of component that have possibility causing shorted, then locate possition on actual mobo. as example pc304, pc305, Pq310(on block charger P.47)
pc406, pc416, pc418 (on block 3V and 5V P.48) do next with other block circuits.
4. Start to set your PSU with limit 1V (Don't more than 1V), solder cable on PL301 then connect to PSU, see your current drawn on display panel PSU. (have idea make cable with alligator clip,very usefull for finding shorted, next time)
5. Set your DMM (digital multimeter) with voltage mode, measure on big coils PL1104, PL1102 next on coils PL702, next on coils block GPU. (0.22UH 20% PCME064T-R22MS0R985 28A ---0.15UH 20% PCME064T-R15MS0R667 36A---1UH_PCMB063T-1R0MS_12A_20% )
6. Next to big coils block RAM, 5V and 3V (1UH_PCMB104T-1R0MH_18A_20% ---1.5UH_PCMB053T-1R5MS_6A_20% ---1.5UH +-20% PCMC063T-1R5MN 9A)
7. Next to coil on block Charger (4.7UH +-20% PCMB104T-4R7MS 8.5A)
All (on step 5,6 and 7) must be have NO VOLTAGES. I worry if high side mosfet or IC PWM internally have shorted.
if you found voltage same 1V or less then stop inject voltage immediately.
if the result is no voltages, focus to capacitor ceramic or component that will be hot
8. Good luck and be careful.

link HD image for help finding many component event without magnifying
https://www.mediafire.com/folder/sgn...A-B111P_Rev.1A)
Thanks to djdzo

[jiroy]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Where is the uploaded schematics ?...

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Google it, you'll find it on s-manuals. More effort, more respect.

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Definitely I refer wrong schematic, since you've mentioned problems on other thread. https://www.badcaps.net/forum/showth...t=56200&page=2
Is this first time experience with shorted B+?

I think I knew correct schematic for this case, it's LA-B111P, right?
1. LA-B111P, B+ connected to other component like IC PWM and High Side mosfet through PL wasn't Jumper pad (1UH +-20% PH041H-1R0MS 3.8A / HCB2012KF-121T50_0805 / FBMA-L11-201209-121LMA50T_0805) the shape like ceramic capacitor, but have more dark color. So be carefull, don't think it was capacitor.
2. provide of your resistance measurement on all big coils.
3. Would Prefer identifying and make list of component that have possibility causing shorted, then locate possition on actual mobo. as example pc304, pc305, Pq310(on block charger P.47)
pc406, pc416, pc418 (on block 3V and 5V P.48) do next with other block circuits.
4. Start to set your PSU with limit 1V (Don't more than 1V), solder cable on PL301 then connect to PSU, see your current drawn on display panel PSU. (have idea make cable with alligator clip,very usefull for finding shorted, next time)
5. Set your DMM (digital multimeter) with voltage mode, measure on big coils PL1104, PL1102 next on coils PL702, next on coils block GPU. (0.22UH 20% PCME064T-R22MS0R985 28A ---0.15UH 20% PCME064T-R15MS0R667 36A---1UH_PCMB063T-1R0MS_12A_20% )
6. Next to big coils block RAM, 5V and 3V (1UH_PCMB104T-1R0MH_18A_20% ---1.5UH_PCMB053T-1R5MS_6A_20% ---1.5UH +-20% PCMC063T-1R5MN 9A)
7. Next to coil on block Charger (4.7UH +-20% PCMB104T-4R7MS 8.5A)
All (on step 5,6 and 7) must be have NO VOLTAGES. I worry if high side mosfet or IC PWM internally have shorted.
if you found voltage same 1V or less then stop inject voltage immediately.
if the result is no voltages, focus to capacitor ceramic or component that will be hot
8. Good luck and be careful.

link HD image for help finding many component event without magnifying
https://www.mediafire.com/folder/sgn...A-B111P_Rev.1A)
Thanks to djdzo

hi, sorry for the late reply. i have to take the PSU from my office first. i already follow the instructions you gave.
1. Yes exactly, mine is LA-B111P.
2. Meassurement on all big coil i can found shows 0 ohm.
4. i set the psu to 1V and connect it to PL301, it shown 1,34A drawn to the board. is it normal?
5. i meassure voltage on the coil you mentioned but none of them show 1V.
So the next step is to find other shorted component right? how hot will that component be? after a few minutes i give 1V to the board, nothing was too hot, just all the coil get a bit warmed up.

Would you please help me what i should do next?
anyway, thank you for your big help until this time

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Where is the uploaded schematics ?...

Sorry, I monitoring this thread from my old phone lenovo A369i, didn't know who the reply it. at first look and I think the owner poster.
As you know many new member who was so lazy for searching many schematic to get attention only.

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

hi, sorry for the late reply. i have to take the PSU from my office first. i already follow the instructions you gave.
1. Yes exactly, mine is LA-B111P.
2. Meassurement on all big coil i can found shows 0 ohm.
4. i set the psu to 1V and connect it to PL301, it shown 1,34A drawn to the board. is it normal?
5. i meassure voltage on the coil you mentioned but none of them show 1V.
So the next step is to find other shorted component right? how hot will that component be? after a few minutes i give 1V to the board, nothing was too hot, just all the coil get a bit warmed up.

Would you please help me what i should do next?
anyway, thank you for your big help until this time

1.---
2. All coil got 0 ohm? very confuse what your measurement, repeat again measure it. (don't apply power when you do that), measure it versus gnd
3---
4. No. it doesn't normal. the current drawn show you too many current to flow to GND, of course due shorted circuit.
5. You measure all of them when you injecting or not? :think: you should measure when injecting! if no voltages, Then focus to ceramic or IC PWM on block 3v and 5v, you should mention what PL that become warm, more descriptive will be more help.

If customer give you time, and you have passion and patience, I'm very pleasure to help you

[jiroy]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Sorry, I monitoring this thread from my old phone lenovo A369i, didn't know who the reply it. at first look and I think the owner poster.
As you know many new member who was so lazy for searching many schematic to get attention only.

He wrote in the thread's first post "Schematics of M/B uploaded." .. I thought maybe a technical issue . No worries friend

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

1.---
2. All coil got 0 ohm? very confuse what your measurement, repeat again measure it. (don't apply power when you do that), measure it versus gnd
3---
4. No. it doesn't normal. the current drawn show you too many current to flow to GND, of course due shorted circuit.
5. You measure all of them when you injecting or not? :think: you should measure when injecting! if no voltages, Then focus to ceramic or IC PWM on block 3v and 5v, you should mention what PL that become warm, more descriptive will be more help.

If customer give you time, and you have passion and patience, I'm very pleasure to help you

ahh, sorry man. I made stupid mistake, i didnt meassure it versus gnd.
Here's the meassurement:
PL1102 17.3ohm
PL1103 17.3ohm
PL1104 17.3ohm

PL902 14.2ohm
PL903 13.2ohm
PL904 13.5ohm

PL502 187.5ohm
PL404 22.08k ohm
PL402 10.15k ohm
PL302 176.1k ohm
PL702 64.3ohm
PL1201 72.1k ohm
PL301 1.4ohm

Yes, i meassure it when injecting. i meassure it again and still no voltages.
After a few more minutes injecting 1V, i found that PU1102 get pretty hot and keep heating up. PL904 and PC1135 get a bit warm (just a bit compared to PU1102).

Actually it's not my customer laptop, it's my cousin. And yes, it's my first time so forgive me is i often make stupid mistake.

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

- Remove PU1102, then measure resistance on PL301 vs GND, should be (hope) high value of resistance. hope we found the culprit.
- Also get attention to PL904 why become warm...:think:....
- Keep in mind don't apply power to the board till the shorted has gone.

[ktmmotocross]

Re: Lenovo Y50-70 Completely dead, no lights at all.

have schematic?


pl301 short?

[jiroy]

Re: Lenovo Y50-70 Completely dead, no lights at all.

Service and schematics ..

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

- Remove PU1102, then measure resistance on PL301 vs GND, should be (hope) high value of resistance. hope we found the culprit.
- Also get attention to PL904 why become warm...:think:....
- Keep in mind don't apply power to the board till the shorted has gone.

hello, i just removed the PU1102 but the the problem still exist. resistance between PL301 and GND keep showing just 1,3 ohm.
So i inject 1v again to PL301, the board draw 1,34A from the PSU, and i start searching which component heat up. I found that the component beside PU1102 got pretty hot so i decided to remove it.
After remove that component(i guess it's a ceramic caps?) PL301 doesn't seen shorted anymore, it shows about 5 mega ohm but the meassurements keep moving. i inject 1v again and my PSU show 0A drawn to the board.
1. What component is that?
2. Is this component the real culprit?
3. is there any possibilities that PU1102 still in good condition? (at the first attempt PU1102 heat up also) or maybe both PU1102 and this component bad?
4. does what i did until this step correct?

i attach a picture of the component.
Still. thank you so much for guiding me this whole time

[meritosari]

Re: Lenovo Y50-70 Completely dead, no lights at all.

1. What component is that?
2. Is this component the real culprit?
3. is there any possibilities that PU1102 still in good condition? (at the first attempt PU1102 heat up also) or maybe both PU1102 and this component bad?
4. does what i did until this step correct?

1. I'm pretty sure it was ceramic caps 10U_0805_25V6K (PC1118 or PC1119, you'll see other one on top side mobo near PL1106).
2. I think YES. Need more test/check to ensure it
3. Put PU1102 back to M/B then check again resistance on PL301. Also check pin to other pin should have no contact (one by one) see datasheet for knowing the pin out.
I think the possibility still good, maybe only impact when you was inject more than 1 min.
4. Pray and test, try connect with original adapter, and see the result.
original adapter have feature to cut out immediatly when shorted detected.
5. Good luck.

https://cdn.badcaps-static.com/pdfs/...7acda540c0.pdf

[didutgendut]

Re: Lenovo Y50-70 Completely dead, no lights at all.

1. I'm pretty sure it was ceramic caps 10U_0805_25V6K (PC1118 or PC1119, you'll see other one on top side mobo near PL1106).
2. I think YES. Need more test/check to ensure it
3. Put PU1102 back to M/B then check again resistance on PL301. Also check pin to other pin should have no contact (one by one) see datasheet for knowing the pin out.
I think the possibility still good, maybe only impact when you was inject more than 1 min.
4. Pray and test, try connect with original adapter, and see the result.
original adapter have feature to cut out immediatly when shorted detected.
5. Good luck.

https://cdn.badcaps-static.com/pdfs/...7acda540c0.pdf

Hello my friend, i've put back PU1102 to the board(hopefully soldered well :p)
1. it seems no more short in the board.
2. Plug in the AC adapter, 20V can now past through PQ302
charging light now light up
3. Can i try to power up the laptop without that ceramic cap? is it ok?