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lenovo thinkpad p50 rev1.0 bios programming issue

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    lenovo thinkpad p50 rev1.0 bios programming issue

    hi everyone

    ive been working on a thinkpad p50 rev1.0.

    i searched the site before hand and found a lot of information and schematics and bios files and got to work diagnosing what the issue was. i followed many threads here and confirmed all voltages were present and components were in good order.

    the initial issue was the screen was replaced by someone else and then would not turn on again and it ended up with me. in my testing it would switch on for a second or 2 and switch off. i took the cmos battery out along with memory and ssd and i got 6 beeps when turned on and would immediately turn off. it did that only 2 times, and once with 4 beeps. after that it would only turn on for a second or 2 with fan spin and then begin to draw current to charge battery. thats its current state

    from the beginning i suspected a BIOS issue, i checked everything i could before getting to chip-off. from what i could see the BIOS chip was U15, a winbond 25q80blnig.

    i am running a CH431 based programmer called "nextprogrammer" ive tested it on a few random bios chips i found on donor boards laying around my lab and it all seems to work fine.

    i soldered the BIOS onto the breakout board to plug into the reader. it detected it straight away and i backed it up twice and once more with the original black ch341a just to be extra safe.

    i then downloaded the bios file (https://www.badcaps.net/forum/showpo...03&postcount=4)

    while trying to write to it i get an error "the buffer size is larger than the ic size" is the chip damaged or did something go wrong or have i got the wrong ic or did i destroy it?

    thanks

    #2
    Re: lenovo thinkpad p50 rev1.0 bios programming issue

    i did notice that the files i read from the chip were 1mb where as the bios files ive downloaded were much larger around 16mb.

    i wrote the original file back onto it and plugged the screen and battery in with memory installed and i got the 6 beeps again and then it switches off. it then goes into charging the battery as seen on my dcpsu.
    when i connect it to psu immediately the power led flashes 3 times..

    with battery connected itll switch on give the 6 beeps switch off and charge battery but you cant switch it back on untill you take the power off and take the battery out. without battery itll just keep switching on for a second and switch off
    Last edited by Thedan55; 11-18-2022, 06:16 PM.

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      #3
      Re: lenovo thinkpad p50 rev1.0 bios programming issue

      25Q80 chip is not the main bios, may be its EC bios. Look for another similar looking chip on the board.

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        #4
        Re: lenovo thinkpad p50 rev1.0 bios programming issue

        the bios chip is directly unter the heatsink between cpu and gpu, near to the cpu. i did program several of these machines.

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          #5
          Re: lenovo thinkpad p50 rev1.0 bios programming issue

          25Q80 (U15) is for thunderbolt firmware, you should look for U5 - SPI_ROM, 16MB (W25Q128FVSIQ, MX25L12873FM2I-10G, N25Q128A13ESEDFF)
          schematics:
          https://www.badcaps.net/forum/showth...hlight=NM-A451
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            #6
            Re: lenovo thinkpad p50 rev1.0 bios programming issue

            Ahhh i did have the wrong one! Dam. I have the schematics and board view. I'm still learning how to read schematics, is there a label on the schematics to identify the BIOS ic for me to look out for in the future?

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              #7
              Re: lenovo thinkpad p50 rev1.0 bios programming issue

              Originally posted by Thedan55 View Post
              Ahhh i did have the wrong one! Dam. I have the schematics and board view. I'm still learning how to read schematics, is there a label on the schematics to identify the BIOS ic for me to look out for in the future?
              they are generally named in schematics SPI_FLASH, SPI_ROM, MAIN_ROM but some laptops have 2 or 3 chipsets, one for EC (Embeded Controller), one for PCH which is Main Bios and one for thunderbolt (is marked as TBT). You can figure out from block diagram.
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                #8
                Re: lenovo thinkpad p50 rev1.0 bios programming issue

                Originally posted by volinakis View Post
                they are generally named in schematics SPI_FLASH, SPI_ROM, MAIN_ROM but some laptops have 2 or 3 chipsets, one for EC (Embeded Controller), one for PCH which is Main Bios and one for thunderbolt (is marked as TBT). You can figure out from block diagram.

                Brilliant thank you!

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                  #9
                  Re: lenovo thinkpad p50 rev1.0 bios programming issue

                  hey all

                  i managed to locate and program the bios but im still getting the same issues.
                  resistance to ground on RTCVCC resistor r31 pin2 4.8ohm with switch up.
                  ol with switch pressed pin 1. ol

                  c262 vint20 i get 20v
                  f6 i get 20v on p1 but no continuity across it


                  c7 pin2 4.8ohm.ol with switch pressed
                  pin one 0.2ohm basically grounded

                  d1 p1 about 5.2 ohms ol with switch pressed

                  c71 pin1 ol

                  pr2 20 both sides
                  pq2 pin 1,2,3, 20v pin 4 10v
                  pq1 pin 1,2,3, 20 pin 4 6.6v
                  pf1 20 both sides

                  i dont understand what this intruder switch is or what its for

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                    #10
                    Re: lenovo thinkpad p50 rev1.0 bios programming issue

                    Update

                    I replaced f6 and the display came to life! I'm so happy. I'm guessing that fuse was connected to the display? I'll have to check the schematic again.

                    I'm so happy. This is maybe the first laptop I've fully diagnosed properly and located issues.

                    Thank you all so much

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                      #11
                      Re: lenovo thinkpad p50 rev1.0 bios programming issue

                      Originally posted by Thedan55 View Post
                      Update

                      I replaced f6 and the display came to life! I'm so happy. I'm guessing that fuse was connected to the display? I'll have to check the schematic again.

                      I'm so happy. This is maybe the first laptop I've fully diagnosed properly and located issues.

                      Thank you all so much
                      F6 is for LED backlight, you had video signal but no luminosity. This happens when noobs change displays with battery connected or worse, with AC Adapter connected.
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                        #12
                        Re: lenovo thinkpad p50 rev1.0 bios programming issue

                        Originally posted by volinakis View Post
                        F6 is for LED backlight, you had video signal but no luminosity. This happens when noobs change displays with battery connected or worse, with AC Adapter connected.

                        Quite certain that's what's happened but the previous person who worked on it.

                        I'm powering it up with my power supply as their original charger is not working right. However the system tells me it doesn't have enough power even though my DCPSU can output 300w and this only needs 170w. I'm at 20v 8.5a.

                        It's this due to the signal pin? I'm using a wire with a dc plug and then the compatible charging pin on my PSU. I'm assuming it can't send the right signal?

                        Separate question
                        What does the intruder pin do?

                        Edit: will it still boot into its Windows installation even after after i flashed the BIOS? It's currently charging on my psu as the battery is dead and doesn't go further as it gives me an error dating battery level is critical my the computed l connected charger isn't powerful enough
                        Last edited by Thedan55; 11-23-2022, 04:37 PM.

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                          #13
                          Re: lenovo thinkpad p50 rev1.0 bios programming issue

                          It booted into Windows! Awesome

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