Hello,
I wonder if anyone can help, I have a Lenovo P2 phone with a black (blank) screen on power up.
A little history:
I bought this phone in this condition back in 2017 ish, from what I remember the seller stated he tried to replace the screen and after he did the phone would not display anything, even on the old screen, which was working just cracked.
Current condition:
The phone powers up, with an initial red led fade on/off (top right) plus vibration pulse and is recognized by the PC as an MTP USB device, however the screen is still blank...
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Re: Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
Hello mcplslg123 and All,
I have found that someone in the forum has already uploaded a BIOS for my board (see link below) and there results are encouraging, so I attempted to flash the BIOS.
My steps in flashing the BIOS:
1. Used a CH341A mini programmer and dumped the BIOS twice.
2. Compared the two dumps (the same).
3. Downloaded the the BIOS bin from ([url]https://www.badcaps.net/forum/showthread.php?t=88463&highlight=Acer+Nitro+LA-E911P+BIOS[/url]).
4....Last edited by SMDFlea; 03-30-2022, 02:35 PM.
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Re: Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
On power up of board (power button pressed) 1.2v is present at pin 2 RD6, The other side of RD6 pin 1 shows 125mv suggesting the line is being pulled down.
The only oddity's that I have found is H_CPUPWRGD is only 1.1v (is this still regarded as high) and isn't H_CPUPWRGD suppose to be high after DRANRST is high, in the start up sequence? (this is with my limited experience on board level repair so I maybe way off)
Some original faults I had not mentioned with this board were: ...
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Re: Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
Update:
I have Checked DRANRST line and to the best of my knowledge/ability I think its ok.
I checked the pull up resistor at RD6 and found the value to be 464Ω (see attached picture) this is within spec, so I'm still stuck.
I guess I need to step back in the startup procedure and see if other lines/signals are present.
Thanks for the info mcplslg123 much appreciated...
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Re: Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
Update:
I have back tracked a few startup steps and found that the PLT_RST signal is not coming out of the PCH.
I have checked as close to the PCH as I could to make sure no PCB traces are damaged however still a no go, so seems to be a faulty PCH?
I could attempt a PCH reflow ?
Any advice would be welcome
Many thanks All.
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Re: Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
Update:
I have removed:
UX1 (LCD PWR_DIS SWITCH) As the IC gets very hot
even without LCD connected, seems to be a short from pin 1 to 5 on IC.
I have tested:
1. RSMRST line @ pin 100 UB1 (EC) = High/Good
2.POWER GOOD/OK Lines:
2A. VR_PWRGD = 3.43v
2B. ALL_GPWRGD = 1.91v ?
2C. H_CPUPWRGD = 1.10v ?
2D. DRAMRST = 0v (should this be around 1.3v?)
3. Two main voltages still missing (maybe more)...
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Acer Nitro AN15-51 (Board LA-E911P) Powers on No display
Hello,
I hope you are all well.
I have an Acer Nitro AN15-51 (Board LA-E911P) that will not display anything no BIOS nothing.
Once power (from AC) is applied, keyboard lights up, fans spin for about 5 sec, CPU, GPU, and PCH start warming up, all seems to start ok, however no display no cap key acknowledgement and no USB activity just USB power.
The below IC's are of concern to me as there temps are high
UL2 (LAN/SD controller IC) gets hot
UX1 (LCD Power dis switch) gets very hot even if LCD is unplugged
UX1 seems...
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Re: Asus GL752V Blowing new MOSFETS
Bad news about this one, I found the CPU has a short on the 1.2v rail :-(
Thanks for all the help.
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Re: Asus GL752V Blowing new MOSFETS
Anybody know the value of PR8604 in attached picture, I'm thinking it might be about 10k?
Many thanks....
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Re: Asus GL752V Blowing new MOSFETS
Hello Guys,
I have done some more digging and found this (see pic attached) DDR PSU controller
I guess for some reason the two FET where energized at the same time resulting in massive current passing through them so BOOM!
I would like to know why so I may put a scope on the controller and view the high and low gate drivers (maybe just a meter in continuity will work to see if there is a short?)
Am I on the right path and is there anything else I should consider?
Anyway...
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Re: Asus GL752V Blowing new MOSFETS
Sorry mon2 I had my "stupid" glasses on, I see what it is thanks....
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Re: Asus GL752V Blowing new MOSFETS
Hello ktmmotocross,
Are you talking about the southbridge I mentioned, or the IC near the blown FET?
Is it a FET driver or a buck controller?
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Re: Asus GL752V Blowing new MOSFETS
Hello mon2,
Thanks for the pictures, however I dont have any frame of reference for the given pics, I dont know the location or what the components are.
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Re: Asus GL752V Blowing new MOSFETS
Hello petehall347,
I did check nearby caps, and used voltage injection (1.2v max) at the stated site, however I didn't find any shorted caps and I'm unsure of the values of the resistors as I have no board info, there is a resistor connecting GtoS on the original blown FET I believe it is very low resistance.
All that said, I need to remove the blown FET's and recheck the board as things may have changed since the FET's blow.
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Re: Asus GL752V Blowing new MOSFETS
Hello SMDFlea,
Yep that is the exact one.
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Asus GL752V Blowing new MOSFETS
Hello All I wonder if anyone can help me,
I'm trying to fix an Asus GL752V.
The laptop turned on with only the BATT/PW LED's showing on the front, no display/POST.
I found that a MOSFET near the top left side of the SSD bay had blown rather aggressively, (black skid mark see pics) I removed the blown MOSFET and tested the one to the left of it, also blown (short on all pins), I tested board for shorts after the removal all seemed ok.
I replaced both MOSFETS and did a short circuit test all still good (well low resistance on right FET from GtoS red flag?)
...
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Re: Asus X550JX 2.0 Laptop Dead
Thank for the confirmation and help, I will remove the IC and test again.
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Re: Asus X550JX 2.0 Laptop Dead
Hello Sephir0th,
I have uploaded some pictures of the various IC's and connector from boardview, with stated voltages rail names.
Also pictures of the actual laptop board with the IC's highlighted.
Please let me know if you require any other info to help.
Many thanks :-)...
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Asus X550JX 2.0 Laptop Dead
Hello All,
I thought I should put this in a new thread.
The issue:
The laptop has no signs of life if AC or battery is connected, apart from a quick flick of light from LED5606 (sometimes).
No 3.3v & 5v power rails, I tested this at the power button connector, (J6201)
I found that the 3.3v rail (J6201 pin1) has a resistance of 1.5ohms to GND first red flag.
I investigated further and found that PU9100 and PU8100 get very warm if not hot once power is connected. (maybe one of them is at fault or under extreme load)
...
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Re: New Members - please post your introductions here
Hello All,
I have been an electronics engineer, tinkerer DIYer for most of my life, taking things apart at an early age (trying to put them back together) just out of curiosity of how things work.
My first adventure in PC's was back in the mid 90's trying to help my Mom install a sound card in her new PC (yes people new PC's back then did not come with everything there do today) we did manage to install the sound card and get it working, boy what a struggle ! but we learnt a lot.
At present I...
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