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Old 12-17-2018, 06:23 AM   #1
caspian
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Default Lenovo G585

Dear forum members,

I have hot a Lenovo G585 laptop with AMD APU and FCH. the laptop does not display anything on the screen. I am still testing it. All voltage rails are present.
The FCH gets hotter than normal. But had tested the laptop 3 days ago. At that time, the FCH used to get just a bit warm. However, the FCH generates its output signals well, such as PLT_RST# and PWRGood.
when the laptop turns on, the screen is black and the webcam light stays on continuously.
I have checked the tiny capacitors located on the FCH chip (see the photo). some of them are shorted. I mean they have 1 ohm resistance to GND on both sides. the other caps on the chip are not shorted. A while ago, I had a HP laptop with AMD FCH on its mainboard. two of the tiny capacitors located on that FCH chip were shorted too.

schematics:
https://www.badcaps.net/forum/attach...7&d=1490606457

Is it normal in an AMD FCH chip to have a few tiny capacitors (located on the FCH chip) to be shorted?
If it is an Intel PCH, I know the PCH is defective. But I do not know about AMD FCH.

thanks
Attached Images
File Type: jpg FCH chip.jpg (36.0 KB, 26 views)

Last edited by caspian; 12-17-2018 at 07:50 AM..
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Old 12-17-2018, 11:03 AM   #2
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Default Re: Lenovo G585

the shorted caps have 0 v when I turn the laptop on. No voltage rail is shorted on the mainboard.
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Old 12-17-2018, 11:15 PM   #3
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Default Re: Lenovo G585

Some of the small caps on amd fch does show continuity in diode mode-that's normal. Did you flashed bios?? Webcam light remaining glowing is more often than not a bios issue on lenovo G580/85.
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Old 12-18-2018, 03:59 AM   #4
caspian
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Default Re: Lenovo G585

KB9012 works fine and controls the fan very good. I will reprogram the Bios IC to see what will happen.
The FCH used to be 50'C when the laptop was fine. Now, the FCH reaches 75'C with black screen 40 seconds after turning on. Does this make sure that the FCH is defective? or is it due to some problem from another IC?

Last edited by caspian; 12-18-2018 at 04:03 AM..
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Old 12-19-2018, 07:38 AM   #5
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Default Re: Lenovo G585

I reprogrammed the Bios and the laptop acts the same. It is not fixed yet. I do not know why the FCH gets 25'C hotter than normal. I do not know what makes the webcam light stay on.

Last edited by caspian; 12-19-2018 at 07:43 AM..
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Old 12-19-2018, 01:23 PM   #6
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Default Re: Lenovo G585

I want to convert this mainboard to UMA. But I cannot find the resistors R682, R683, R684, and R685. No boardview is available. Does anyone know where these resistors are located on the mainboard?

Last edited by caspian; 12-19-2018 at 02:30 PM..
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Old 12-19-2018, 11:48 PM   #7
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Default Re: Lenovo G585

Post closeup photo of amd chips.
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Old 12-20-2018, 02:12 PM   #8
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Default Lenovo G585 DIS to UMA Conversion

Finally, I managed to locate those resistors. I attached two photos on how to convert the mainboard LA-8681P from DIS to UMA. Just two resistors have to be moved from one side the mainboard to the other side of the mainboard. Nobody else did it so far on this mainboard.
I moved the two resistors. but my laptop did not get fixed. I am sure the two resistors are correctly found. after this conversion, the FCH still thinks the mainboard is DIS. I do not know why. probably due to defective FCH or defective APU or something else. maybe I need to use a UMA version of Bios. but nobody has mentioned any available Bios dump is UMA or DIS. probably, both are the same. I do not know.
I even disconnected power to the GPU chip. but there was no change.
Attached Images
File Type: jpg DIS-to-UMA1.JPG (81.9 KB, 17 views)
File Type: jpg DIS-to-UMA2.JPG (74.4 KB, 17 views)

Last edited by caspian; 12-20-2018 at 03:15 PM..
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Old 12-20-2018, 06:26 PM   #9
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Default Re: Lenovo G585

Did you try to heat up the FCH a littte bit (120C)?
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Old 12-21-2018, 05:12 AM   #10
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Default Re: Lenovo G585

I did, but there was no change.
I do not know why the FCH does not recognize the mainboard as a UMA mainboard after converting it to UMA. Maybe, I also need to change something else too such as reprogramming Bios using a UMA dump.
I have attached my Bios dump for Lenovo G585 with a GPU. If someone has a Bios dump from a Lenovo G585 that has no GPU, please upload it here for me.

Last edited by caspian; 12-21-2018 at 05:44 AM..
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Old 12-22-2018, 10:01 AM   #11
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Default Re: Lenovo G585

note: to convert this mainboard to UMA, sometimes it is required to move just one of the two resistors that I demonstrated in the photos. So test them yourself to see which one works.
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Old 12-22-2018, 10:08 AM   #12
caspian
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Default Re: Lenovo G585

I discovered something:
- when I use my original Bios, the mainboard gets off if I press the power button. but the FCH does not understand the UMA conversion.
- when I use the Bios provided by SMDFlee, the mainboard does not get off if I press the power button. but the FCH understands the UMA conversion well.

Bios provided by SMDFlee:
https://www.badcaps.net/forum/showthread.php?t=73763

using both the Bios dumps, it has black screen and the webcam stays on.
So, is it possible that the FCH is fine?
Does it need another bios dump to get fixed?
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Old 12-23-2018, 05:33 AM   #13
caspian
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Default Re: Lenovo G585

Although the mainboard is reconfigurable, it seems the original Bios dump does not have the capability of conversion to UMA. that means it works only if there is a healthy GPU on the board. the GPU of my laptop may be defective.
It seems the manufacturer wrote the original Bios to work only for GPU-based mainboard. that may be why nobody has successfully converted this mainboad to UMA on the Internet. However, I am not sure.

has anyone converted any AMD-based laptop to UMA so far?

Last edited by caspian; 12-23-2018 at 05:35 AM..
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Old 01-24-2019, 05:12 AM   #14
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Default Re: Lenovo G585

Has anyone converted any AMD-based laptop from DIS to UMA graphics so far?
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Old 01-24-2019, 04:00 PM   #15
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Default Re: Lenovo G585

I think I am having the same issue with my LA-8127P motherboard where the FCH is heating up after turn on. The fan will start soon after turn on to keep the CPU and GPU cool, but I get no video (VGA). Mine is also a AMD. I found the two resistors to change over to make it UMA only, and will give it a shot. I don't have a different BIOS file to load though.
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Old 01-25-2019, 01:51 AM   #16
caspian
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Default Re: Lenovo G585

In general, I do not know whether DIS-UMA conversion works in AMD-based laptops or not?
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Old 01-25-2019, 03:40 AM   #17
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Default Re: Lenovo G585

Hi
Try This
Attached Files
File Type: rar G585_MAIN.rar (1.58 MB, 2 views)
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Old 01-25-2019, 05:55 AM   #18
caspian
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Default Re: Lenovo G585

thank you. I have tries this bios before with no result.
Does anyone know whether DIS-UMA conversion works in AMD-based laptops in general?
or is it just for Intel-based laptops?
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