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Answer selected by ant3202 at 07-09-2025, 04:10 AM.
Thank you stj and truclacicr, TL431 works
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it *may* be a copy of a TL431
what does it do?
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Thank you stj and truclacicr, TL431 works
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This is a guide that I am writing for helping others to replace their MEC1503 EC chip if it breaks (or to get around an inconvenient prompt to the BIOS). This forum has been extremely helpful to me so I would like to contribute to help others. I will tell you right now that this task is very difficult to do. You MUST have experience and tools to do precision micro-soldering, BGA reballing, trace repair, and general laptop repair skills.
There are some specialty tools needed to do this task. The replacement MEC1503 chips can be acquired from Aliexpress. Do not buy the bare chips as... -
Hi
I have a very strange issue with the BIOS SPI chip of an ASRock B650M PRO RS motherboard.
The SPI chip is an Winbond 25Q256JWEQ model (1V8).
The motherbaord doas not POST - it lits only CPU and DRAM EZ Debug Leds, and stays that way forever.
The Flashback function of the motherbaord is also not working, despite all instructions followed correctly - I'm 100% sure of this.
I have then desoldered the chip, backupped the contents, and tried to earease the chip in order to program stock image, but the chip is locked by status registers SREG2 (TB) and SREG6... -
Hi, Im trying to find the area on the chip that contains all of my laptops information, but I havent found it. The laptop won't turn on anymore. I was updating the BIOS, and it was supposed to reboot itself, but it wouldnt turn back on. I ve tried every possible solution, every alternative on Lenovo forums, everywhere; I ve taken it to technicians, and no one has been able to fix it. I've already read the chip that contains the BIOS (Winbond 25Q128JSVQ) and searched for my laptops data, but they're nowhere to be found. I only find scribbles and lines of text indicating errors. Has anyone had a... -
Asus Vivobook 15 (board X513ea R2.0) gone dead when user plugged an iPhone cable into the USB-C port during boot. Now there's no LED light, no power at all. I checked all MOSFETs and capacitors, no shorts found. The board only has 3.3V and 5V present, no other voltages.
I injected 3.3V into the EC chip power rail (ITE IT5125VG 128), and it draws 80mA, while the 3.3V LDO chip RT8249C has a max output of 100mA. I checked the boardview and found there are only two chips on this 3.3V rail, EC and Realtek audio chip. So I think EC could be the problem.
I found the EC chip...09-14-2024, 02:09 AM -
Hello guys,
I would like a quite old but still good 800 W ATX PSU to be repaired. The problem was an extremely heavy coil whine coming from the small secondary transfomer on the PCB.
I desoldered it hoping the references on the upper side would allow me to find a adequate replacement part. Sadly the written references drove me nowhere but to the manufacturer (I-MAG). I sent them a message like a bottle in the see asking them to send me a datasheet of the transformer. And... They responded ! I received a kind of datasheet (see attachment) but my competencies do not allow...
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