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Search: Posts Made By: piernov
Forum: Schematic Requests ONLY! Yesterday, 01:29 PM
Replies: 106
Views: 75,424
Posted By piernov
Re: Macbook Air 820-00165-A schemati and boardview

https://badcaps.net/forum/showpost.php?p=707034&postcount=2
Forum: Troubleshooting Laptops, Portable, and Mobile Devices Yesterday, 03:42 AM
Replies: 2
Views: 38
Posted By piernov
Re: Acer da0zq0mb6e0 rev e no power

Everything is fine here. Measure power rails.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices Yesterday, 03:39 AM
Replies: 2
Views: 38
Posted By piernov
Re: Schematics notation Q

"K" is for "kilo", here it's implied it is kiloohms for resistors.
"F" is a tolerance code, 1% in this case.
"4" is the package size, "0402" in this case. ("2" would be "0201")
Forum: Troubleshooting Laptops, Portable, and Mobile Devices Yesterday, 03:25 AM
Replies: 12
Views: 188
Posted By piernov
Re: Hp 450 dead

Maybe the schematic is wrong and something is pulling TRIP1/TRIP2 of the TPS51123 to ground. And maybe the LED is powered by the 5V LDO instead.

So ADP_PRES is 3.3 on the other board? And it was...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-21-2020, 12:59 PM
Replies: 3
Views: 72
Posted By piernov
Re: 820-2915-B Chime, Boot to OS, Hear sounds, but No Video

Dead dGPU doesn't necessarily prevent from booting into macOS. Sometimes yes, sometimes no.
If you have image but not backlight when forcing iGPU, then at least the issue with dGPU has been taken...
Forum: BIOS Requests ONLY! 10-21-2020, 04:48 AM
Replies: 16
Views: 1,397
Posted By piernov
Re: Need Bios Laptop Asus N551J/N551JK

If you don't want to take people advice why come here?
You asked about keyboard backlight issue, he gave you the answer to fix it. If you are not happy for whatever reason, just leave. Thanks.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-21-2020, 01:30 AM
Replies: 3
Views: 72
Posted By piernov
Re: 820-2915-B Chime, Boot to OS, Hear sounds, but No Video

820-2915 will of course have a dead GPU in any case.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-21-2020, 01:27 AM
Replies: 12
Views: 188
Posted By piernov
Re: Hp 450 dead

EN_3V_5V is ENC signal for TPS51123.
According to datasheet, ENC: "Channel 1 and Channel 2 enable input. Pull up to the voltage ranging 3.3-V to 5-V to turn on both switcher channels. Short to...
Forum: Troubleshooting Computer Displays 10-20-2020, 12:37 PM
Replies: 2
Views: 483
Posted By piernov
Re: Samsung S27C450B BN41-01916A dump request

Here is the firmware that should be working.
Forum: Troubleshooting Computer Displays 10-20-2020, 12:36 PM
Replies: 2
Views: 483
Posted By piernov
Re: Samsung S27C450B BN41-01916A dump request

I think (and really hope) this one is finally fixed. What a nightmare.

Bought another mainboard since I couldn't find the firmware.
With "new" mainboard, it could turn on and work, but it'd...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-20-2020, 11:10 AM
Replies: 6
Views: 100
Posted By piernov
Re: A2289 Board 820-01987-A Dead?

I assumed it was always 0V since for the other power rails you listed 2 measurements.
So issue is on PPVCC_S0_CPU instead, but it's handled by the same controller, but the VRM chips are U7210 and...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-20-2020, 07:16 AM
Replies: 6
Views: 100
Posted By piernov
Re: A2289 Board 820-01987-A Dead?

I don't have enough experience on these boards to know what could cause VCCSA not to come up after CPU_VR_EN_R comes up.
Could be an issue with U7100, U7270 or a component around them or the CPU...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-20-2020, 05:26 AM
Replies: 6
Views: 100
Posted By piernov
Re: A2289 Board 820-01987-A Dead?

I assume Apple refused to take it under warranty?

Voltage on CPU_VR_EN_R?
Exact resistance to ground on PPVCC_S0_CPU, PPVCCSA_S0_CPU and PPVCCGT_S0_CPU?
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-20-2020, 03:26 AM
Replies: 12
Views: 188
Posted By piernov
Re: Hp 450 dead

If EN_3V_5V is high then U6100 should produce VRP5V0A and VRP3V3A.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-20-2020, 03:22 AM
Replies: 51
Views: 1,138
Posted By piernov
Re: Asus R702UA dead (missing voltage)

RTCRST# resets the Real Time Clock inside the PCH when it's pulled low. It also has the side effect of triggering a "clear CMOS", ie. resetting BIOS settings to the default.
The PCH cannot work if...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-19-2020, 02:36 PM
Replies: 51
Views: 1,138
Posted By piernov
Re: Asus R702UA dead (missing voltage)

The cap on RTCRST# is required, high chances of the PCH not initializing properly if it's missing.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-19-2020, 02:26 PM
Replies: 12
Views: 188
Posted By piernov
Re: Hp 450 dead

EN_3V_5V present or missing?
Check resistance to ground on 3V/5V LDO as well.
Also check voltage on EC pin 14 and make sure 3.3V makes its way to VSTBY pins.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-18-2020, 05:10 AM
Replies: 17
Views: 741
Posted By piernov
Re: Lenovo x1 carbon Gen 2 No POST Dislay

@NiroPall 's issue is different. His machine can boot into Windows.

There is a widespread motherboard issue on X1 2nd gen which seems related to the CPU. Some people say that giving some heat to...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-17-2020, 08:40 PM
Replies: 22
Views: 383
Posted By piernov
Re: 820-2915 no video

"It could be something related to audio circuit like U6880 or U6201."
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-17-2020, 10:42 AM
Replies: 9
Views: 203
Posted By piernov
Re: ASD Links Non existant

Google "Apple Service Diagnostics (2005-2013)"
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-15-2020, 05:42 PM
Replies: 22
Views: 383
Posted By piernov
Re: 820-2915 no video

The speakers are plugged in, right?
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-15-2020, 07:44 AM
Replies: 22
Views: 383
Posted By piernov
Re: 820-2915 no video

External display requires working dGPU anyway. And dGPU is probably dead.
Even with a dead dGPU it should beep without RAM, but it may not POST properly with RAM.
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-14-2020, 01:04 PM
Replies: 9
Views: 242
Posted By piernov
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-14-2020, 03:19 AM
Replies: 2
Views: 118
Posted By piernov
Re: Laptop Asus F541UA(motherboard X541UVK Rev 2.0)spilled coffee wont boot

Same voltage on +VCCCORE with and without RAM? Always stays at 0.98V?
Forum: Troubleshooting Laptops, Portable, and Mobile Devices 10-14-2020, 03:16 AM
Replies: 1
Views: 83
Posted By piernov
Re: lenovo g710 gpu ram problem

The VBIOS must have the profiles for the new VRAM configuration, and you must change the VRAM strapping resistors to select the correct profile. Better put the same VRAM as originally on the board....
Showing results 1 to 25 of 500

 
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