The problem is solved by replacing the loop. The situation is very confusing due to the fact that with the old loop, the native board (X240) works and displays the image normally, and the two boards (X250) do not display anything on the matrix, although the platforms are identical (VIUX1 NM-A091 Rev:1.0). In addition, on the Lenovo website, in the catalog of factory components, absolutely identical cables (identical part numbers) are specified for all three laptops (by serial numbers). Thanks to [B]rogfanther[/B] for the suggestion to replace the loop, I listened and got the right result.
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This matrix is new, works (displays) with the original X240 motherboard (flex cable from X240).
I thought about the flex cable, but there is no flex cable for X250, besides, the schematic diagrams for X240 and X250 are the same (VIUX1 NM-A091 Rev:1.0 platform).
The LCD CONNECTOR connector (J10) has no modifications according to the schematic diagram. I checked the complete set (matrix flex cable) on the Lenovo website in the "Details" section
on X240 Laptop (ThinkPad) - Type 20AL (original board) and on X250 Laptop (ThinkPad) - Type 20CL (one of the purchased boards),...
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Lenovo X240 - motherboard replacement for X250, no image.
Friends. I beg you to help me in this situation.
Lenovo X240 with a video problem. Native Intel drivers are not installed,
after installation, a black screen. It works with the standard Microsoft driver.
Understanding that there are problems with the video core,
I ordered a motherboard from Lenovo X250.
The laptop turns on, starts up, there is no image on the internal display.
The image is output to the external monitor.
I ordered another motherboard from Lenovo X250.
The laptop turns on, starts up, there is no image on the internal display.
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Thanks to CyberDe@th for providing the dump.
Unfortunately the situation remains the same.
All supplies are raised (except +VCC_GT).
According to "Power Up Sequence", DRAMRST# is not removed.
According to measurements on QH4:
2,5 pin (+3VS) - PowerOff - 0V, PowerOn - 3.3V
1 pin (PCH_SMBCLK) - PowerOff - 0V, PowerOn - 3.3V, after switching on one packet (QH4_1pin).
6 pin (SMBCLK) - PowerOff - 3.3V, PowerOn - 3.3V, after switching on one package (QH4_6pin).
4 pin (PCH_SMBDATA) - PowerOff - 0V, PowerOn - 3.3V, after switching on one...4 Photos
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Thank you. I heard and read about VCCGT, but I wasn't sure. Thanks for confirming.
DRAMRST# is missing (or rather “noise” is about 50 mV).
More precisely, here is H_DRAMRST# (PCH output, pin# BC14), via RD31 (short), to DDR4_DRAMRST#, with a pull-up to 1.2V_DDR.
I checked this chain, everything is intact, the resistors match. RESET is not cleared.
By currents (without peripherals, only RAM):
1. By +DC_IN (Main Power):
With ram stick - 1.3A (1.35A with warm-up)
Without ram stick - 1.2A (1.25A with warm-up)
2. By +1.2V_DDR:...
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Dell Precision 5510, AAM00 LA-C361P Rev:2.0 turns on, no image.
Hi.
I kindly ask you to help me solve the problem.
Dell Precision 5510, motherboard AAM00 LA-C361P Rev:2.0
The board turns on, there is no image.
Read more. When the power supply is connected, the front panel indicators light up briefly.
When you press the power button, the button indicator lights up. The board works
there is no image, there is no matrix initialization, there is no image on HDMI.
When turned on, the fans do not spin, but when they warm up they start spinning.
When you turn off the button, the fans spin up to full speed for a short...
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[FONT=Calibri]What possible solutions might there be?
It is very confusing that identical boards have the same fault (symptoms).
Thank you.[/FONT]
[FONT=Calibri]What possible solutions might there be?
It is very confusing that identical boards have the same fault (symptoms).
Thank you.[/FONT]
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I turned off DB2/DB3/DB4 sequentially, then turned it off in different combinations, also turning off all diodes.
Unfortunately, I did not get a positive result. The board does not start, shuts down after 4-5 seconds.
Signals via “PWR Sequence” remained the same, starting from PM_SLP_S5#, ESPI_RST# are missing.
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Acer Aspire 5 a515-52g, EH5AW LA-G521P Rev.1a does not start.
Hi goodday to all.
I really ask for help.
There are two motherboards (absolutely identical) Acer Aspire 5 a515-52g, EH5AW LA-G521P.
Both boards have exactly the same fault symptoms. It turns on, the power indicator lights up for 5 seconds, turns off (the fan does not spin).
Both boards are flashed with Bios Main and Bios EC from the “Bios Acer A515 LA-G521P FULL TEST” topic. XM25QH128AHIG replaced by W25Q128JVSIQ (also NOR-FLASH, XM was not detected by the programmer). On one of the boards, KB9022 was changed, followed by firmware. The fault persists on both boards....
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Hello.
Electronic engineer. I worked in service centers for 15 years, mainly repairing laptops. Now I have switched to working in the production of electronic equipment (medical), but I continue to repair laptops in my personal time.
I accidentally came across the forum and saw a lot of useful information.
Thank you, I really liked the forum. Deadlock situations often arise, and help from other participants is often needed.
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