MARHD
Member
Last Activity: 06-03-2025, 12:36 PM
Joined: 07-07-2018
Location: Cape Town
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PCH ended up being bad, got another board to try fix instead. Might make another post. -
Could someone explain to me the base requirements for the ThinkEngine and MEC EC to work and enable the cpucore FETs etc. For instance does it need comms from any other IC, or does it just need a particular standby voltage, does the CPU need power from elsewhere, etc. The block diagram doesn't do a good job of explaining that IMO....
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For reference, schematic: [url]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/schematic-requests-only/77167-required-t480-nm-b501-schematic?p=1479471#post1479471[/url]https://For reference, schematic: [u...t1479471[/url]Leave a comment:
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Did some further checks. It seems VCC3B_DRV, VCC5B_DRV, B_DRV, B_ON and A_ON are low. So maybe a faulty ThinkEngine or MEC1653, which would suck.
I will continue testing tomorrow, any further feedback would be appreciated.Leave a comment:
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Some additional information. All 4 of the PWM pins of the NCP81218MNTXG (PU401), measure ~1.8V with a multimeter (Don't have my scope with me to check for PWM). But the DRVON pin which should enable the switching FETs, is low. Also, PR415 which is the DRVON series resistor is not placed. Not sure how the switching FETs are supposed to be enabled if this resistor is not present. I'm probably missing something.
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3646071}[/ATTACH]...Leave a comment:
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Yes, sorry I should have mentioned, that is how I am currently testing it. Charger only, no battery, that is how I measured the voltages above as well. I also do not have a CMOS battery if it makes a difference.Leave a comment:
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Lenovo T480 NM-B501 charging but not turning on.
Hi everyone.
I would like some assistance troubleshooting my laptops fault. It charges the battery (red light on), but does not turn on.
With only the charger connected (board removed from case), I measure the following major voltages:
- VINT20_IN = 20V
- VSYS_OUT = 10.2V
- VSYS = 10.2V
- VDDA = 6v
- VCC5M = 5v
- VL5 = 5V
- VCC3M = 3.3v
- VCC1R0_SUS = 1v
- VCC1R8_SUS = 1.8v
- VCCST = 0v
- VCCSTG = 0v
- VCCCPUCORE = 0v
- VCCGFXCORE_I = 0v
- VCCSA = 0v
- VCC1R2AP = 0v
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Re: Dell Inspiron 5748 - Intel Graphics wont work
There is no bios setting to turn the internal graphics on or offLeave a comment:
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Re: Dell Inspiron 5748 - Intel Graphics wont work
OK so I just tried to install the Intel drivers while connected via team-viewer, and it seems that the actual driver is installing properly, but the screen goes black as soon as its installed. I can use the computer via team-viewer, so I went to check the displays, and it seems that the Intel graphics driver isn't able to detect the laptops internal monitor, is there anyway to get it to detect it?Leave a comment:
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Dell Inspiron 5748 - Intel Graphics wont work
Hi there
Hope someone can help me with this problem I`m having on my sisters laptop.
Dell Inspiron 5748, win 10 or win 8.1 (Have both on separate disks for testing),
Intel i7-4510U, Nvidia GT-840m
If I have the Intel graphics enabled all I get is a black screen and if i try plugging it into a monitor it doesn't pick it up. If i have the Intel graphics disabled everything works fine except its permanently running on the GT-840m so battery life is bad. I thought it was a windows 10 problem because it came about after an update, but that was a long time...Last edited by MARHD; 01-30-2019, 09:23 AM. -
Re: Acer 5760G - Quanta ZRJ dead, no power
Ok so I'm going to replace it, but I'm not sure of the value for the resistor. The datasheet says 2.2_6 what value is that exactly? Is 6 the number of zeros?...Last edited by MARHD; 01-23-2019, 04:03 PM.Leave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
AHA I shorted the resistor and the laptop turns on! is it safe to just remove it, or should I replace it?Leave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
I can remove it, or short it?...Leave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
So remove L26 and C579? and then check the resistor again? Or remove all of these caps also?...Last edited by MARHD; 01-23-2019, 02:08 PM.Leave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
which other capacitors?
and what do you want me to test once i remove it?...Leave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
R418 has 3.3v on the U22 side, and 2.5v on the other side.
I checked the Bios pin 8 on the C586 capacitor, and it was 3.3v, the other side of the cap was low voltage. you can see on the pic...Leave a comment:
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Re: Motherboard schematics archive?
Does anyone have the boardview for an acer 5760G, its a Quanta ZRJ motherboard rev: c. I cant find it anywhereLeave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
PL14 has stable 3.3v on both sides.
Pin 95 of u22 has 1v.
Pin 102 of u22 has 2.5v
Pin 19 of u22 has 2.5v
But pin 93 of u22 has 3.3vLeave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
Ok for the one switch that was 3v it is now also 1v, not sure why. Also the led above the power switch has 3v, which is odd since it is so closeLeave a comment:
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Re: Acer 5760G - Quanta ZRJ dead, no power
Just to make sure, which are the two mosfets i can check for 19v on?Leave a comment:
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