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    Shorting a EEPROM chip

    I posted this on a older thread I have and just wanted to make a new thread in the event that someone has some questions later in life this might be easier to come across.

    Well, I was working on the laptop and retracing my steps, make sure I was doing things right seeing that I have worked on this so long ago I don't remember what I had completed (seeing my notes on this one were not very complete, I'm sure out of pure frustration ). So, I want to make sure I'm shorting this BIOS chip properly, I found a webpage that says you have to short either 2 & 7, 3 & 6 or 4 & 5... I have done all 3 of these combinations with no results! I believe I have found the schematics for this chip, but seeing the actual chip is obsolete I'm going off of an ROHS version that I think is the same. Also, I took a picture of the chip itself for ID purposes.

    If someone could please help me and just run through the process of shorting the chip to verify that I'm doing this all properly and to make sure I have done the right pin combination, I would be in debt to you! lol! Thank you for all the help that everyone has provided thus far!

    Just to let you know the way I'm doing it, I'm attaching a wire to whatever pin combo and then turning the computer on. Maybe I don't understand why these combos, from what the schematics shows, it really doesn't make any sense to me. Also, this laptop has NO BIOS battery but a larger surface mounted cap, I don't understand how the settings stay set if there is nothing there to keep power going to it. Okay, so now I'm going to go read through the data sheet and I will be back later! Thanks!

    Thank you in advanced,
    Peter

    Attached is an image of the chip and a data sheet for 24c02-x
    Attached Files

    #2
    Re: Shorting a EEPROM chip

    Thats a super cap which effectively IS the battery. What kind of laptop are we talking? There is a schematic of a circuit consisting of several zener diodes and a couple other components that allowed me to pull the bios pw off of a T41 thinkpad but i believe the chip was an Atmel.

    Comment


      #3
      Re: Shorting a EEPROM chip

      Originally posted by 2andrewd View Post
      Thats a super cap which effectively IS the battery. What kind of laptop are we talking? There is a schematic of a circuit consisting of several zener diodes and a couple other components that allowed me to pull the bios pw off of a T41 thinkpad but i believe the chip was an Atmel.
      This is a Dell Latitude C840. So, I was thinking about this while I was out and about today. The cap is larger for an SMT on "this" board per-say but, I don't think it would be big enough to support the chip on standby for that any long duration of time. I took another look at it and the leads seam to be going to the Intel chip above the the cap and the BIOS chip. Now there is yet a smaller cap to the left that'S between pin 8 & 7, but there is NO WAY, this SMT is holding the memory of these settings. I'm going to track the other pins and see what I can come up with a little later or tomorrow and I will post what I find! Maybe I'll play with my microscope and take some pictures as well. Thank you for responding and the information! By the way I looked for schematics on the board it's 06G040 rev.A03.

      By the way I need to throw out there that all the USBs and drives (other than the HDD) is locked from BIOS and I can't change anything until I get this taken care of.

      Again, thank you and I'll be back to post some finding soon!

      Thank you,
      -Peter

      Comment


        #4
        Re: Shorting a EEPROM chip

        read through this thread.

        Comment


          #5
          Re: Shorting a EEPROM chip

          Originally posted by 2andrewd View Post
          read through this thread.
          Nope... Tried their magic password not working, didn't think it would though, I think it really goes system for system though. Also, I'm not able to run the DVD drive, If I was able to I would have tried flashing the chip or even trying to run some kind of software to crack it (even though I have heard it does NOT work for Dell on many pages). Also, I found a little typo in something I stated above. I meant to say the larger cap does NOT go to the BIOS chip it's connected to the Intel chip right above it. I have to get some sleep, but I'll be squaring off with my nemesis (Dell Latitude C840) in the morning. I'm sure I will have another black eye for my next post as well, but I'm up for the education! Thanks again for the link and your help!

          Thank you,
          -Peter

          Comment


            #6
            Re: Shorting a EEPROM chip

            Let me ask what i should have asked to begin with... Specifically what is locked via pw? Bios? h.d.?

            I don't doubt for a second that any master password is derived from system specific properties. I only glanced at that thread but it was though folks would pass over their info and have a mpw given in response... Hmm. So you have no way to boot separate media of any kind? Did the thread i linked have more detailed info on pin shorting? I doubt this will work but here is your cmos battery location.

            Comment


              #7
              Re: Shorting a EEPROM chip

              Yea, there is no CMOS battery on this one... this is why I'm having such an issue. I have been religiously repairing electronics for about 6 years and this is the first computer that I have seen that doesn't have a CMOS battery in there AT ALL. As for all I/Os I havd nothing, no access to USB ports, DVD drive, NOTHING! Lol! All of these items are disabled in BIOS and I'm not able to turn them on without the BIOS admin password (that I don't have). I have tried codes in BIOS, I have tried the reset the memory moduals through MSDOS. I have tried to jump the the BIOS chip (not fully understanding if I have done this properly). I'm running out options to try with no luck thus far I'm debating swaping out the chip itself, but I'm not sure if the 24c0w6 IC has built in memory or is it linked to a memory modual. Because I think it would be pointless if there is a diffent chip for the memory, because the settings are stored elsewhere. Again, I need to go over the data sheet, it should tell me this info.

              Comment


                #8
                Re: Shorting a EEPROM chip

                Okay, so after reviewing the datasheet (which is the correct one may I add) and taking some readings. Pin #8 is the Vcc and when the computer is off WITH the external DC power supply being ran to it, it is reading a +3.5v with the DC power supply being removed it reads 0.1v (could be 0v)...
                The 24C02W6 IC has a device reset within it. The process of reset is just like any other BIOS chip, which is dropping the Vcc below the power-on-reset threshold which in this case is +2.5v... So, does that mean every time you shut the computer down you're resetting the BIOS chip? The Vcc drops to nothing well at least under the 2.5v threshold that's needed, so by the looks of the data sheet it should be reset when you pull the power wire out. Below is the Device Reset information from the Data sheet:

                2.4.3 Device reset
                In order to prevent inadvertent write operations during power-up, a power-on-reset (POR) circuit is included. At power-up (continuous rise of VCC), the device does not respond to any instruction until VCC reaches the power-on-reset threshold voltage (this threshold is lower than the minimum VCC operating voltage defined in Table 6, Table 7 and Table 8). When VCC passes over the POR threshold, the device is reset and enters the Standby Power mode. The device, however, must not be accessed until VCC reaches a valid and stable VCC voltage within the specified [VCC(min), VCC(max)] range.
                In a similar way, during power-down (continuous decrease in VCC), as soon as VCC drops below the power-on-reset threshold voltage, the device stops responding to any instruction sent to it.

                Note: Min Vcc for this IC is 2.5v and the max is 5.5.
                Pin# 8 Vcc, Pin# 4 is ground (Vss)

                If I was going to short it I would connect Pin # 8 to Pin # 4, if I did this while the computer was on it should give it a short, but will it damage the chip?

                -Peter
                Last edited by Peter9DO; 09-30-2012, 06:00 AM.

                Comment


                  #9
                  Re: Shorting a EEPROM chip

                  is there a Service Tag and Express Service Code on the bottom of your Latitude?

                  Comment


                    #10
                    Re: Shorting a EEPROM chip

                    Service Tag# FWTHJ11
                    Express Service Tag# 34636179349

                    Comment


                      #11
                      Re: Shorting a EEPROM chip

                      i will see if i can get the code for you.

                      Comment


                        #12
                        Re: Shorting a EEPROM chip

                        Originally posted by 2andrewd View Post
                        Let me ask what i should have asked to begin with... Specifically what is locked via pw? Bios? h.d.?

                        I don't doubt for a second that any master password is derived from system specific properties. I only glanced at that thread but it was though folks would pass over their info and have a mpw given in response... Hmm. So you have no way to boot separate media of any kind? Did the thread i linked have more detailed info on pin shorting? I doubt this will work but here is your cmos battery location.
                        By the way, I was able to find the BIOS battery, I though that was a little weird, for one not to be in it... The way they had that thing tucked away you will never see it and they run it through the same ribbon wire as the touch pad. where normally it has it's own port on the MOBO. Well, I unplugged it and went around my process with no kind of luck other than the clock being reset... Oh well!

                        Originally posted by vinceroger69 View Post
                        i will see if i can get the code for you.
                        Thank you! - I have tried a couple of codes with no luck thus far... But hell, If your willing to lend a helping hand I will be more than willing to give it a shot! Thank you again for the help!
                        It's showing that the admin security is enabled, however the only way to turn it off is to put a password for the configuration setup password in...

                        Comment


                          #13
                          Re: Shorting a EEPROM chip

                          Try Q5UQN8HQ as the password.
                          Machina improba! Vel mihi ede potum vel mihi redde nummos meos!

                          Comment


                            #14
                            Re: Shorting a EEPROM chip

                            hi i should be able to help you i have to software for this very kind of issue. when you type the password wrong three times it should go into lockout and give you error number i need that number to generate you a master password, this is how most modern bios run, some just have a master password for override. i need to know who made your bios if you can get that info for me as well.

                            Eg. Phoenix,American Megatrend etc...
                            Last edited by heavymachines; 09-30-2012, 03:23 PM.

                            Comment


                              #15
                              Re: Shorting a EEPROM chip

                              Originally posted by ReverendJones View Post
                              Try Q5UQN8HQ as the password.
                              Nope didn't work... I honestly think I'm going to try to make an EEPROM programmer out of my Arduino Uno and program a new chip. The chip is only $0.39 at Mouser.com, however I have never done this type of programming. I will give it a shot though! Thank you for the help! I honestly think this is the only way I will be able to remove this password. I can't flash it or reset it any other way.

                              Originally posted by heavymachines View Post
                              hi i should be able to help you i have to software for this very kind of issue. when you type the password wrong three times it should go into lockout and give you error number i need that number to generate you a master password, this is how most modern bios run, some just have a master password for override. i need to know who made your bios if you can get that info for me as well.

                              Eg. Phoenix,American Megatrend etc...
                              This thing is not locking up, I entered 100 wrong numbers in a sitting... Also, this does not say who the manufacture of the BIOS is, all it gives me is the version which is A08, I even went on the website and checked for the driver update to see if they would have the manufacture listed for the update and all it says is Dell... Thank you for the help though.

                              I have taken some screen shots of what I'm looking at. The first image is what the screen looks like when I'm on the Admin Password and the information it gives you, telling you that to unlock it you must put in the Configuration Password in. The 2nd image is when I select the Configure Password field, you will see ********* and then you enter the password and it will then proceed to tell you invalid and beep at you. You can do this 100 times nothing changes. Any further suggestions before I use this as a target?
                              Attached Files

                              Comment


                                #16
                                Re: Shorting a EEPROM chip

                                Is FloppyPack a company that makes BIOS software?

                                Comment


                                  #17
                                  Re: Shorting a EEPROM chip

                                  I have a A08 bios in my dell Latitude,
                                  My (Systems information) says that, Dell is the bios manufacturer
                                  If thats any help.

                                  BIOS Version/Date...............Dell Inc. A08. 23/12/2005
                                  SMBIOS Version...................2.3
                                  Last edited by trebo; 10-01-2012, 02:13 AM. Reason: alteration sorry

                                  Comment


                                    #18
                                    Re: Shorting a EEPROM chip

                                    Thanks Trebo!

                                    Comment


                                      #19
                                      Re: Shorting a EEPROM chip

                                      Originally posted by Peter9DO View Post
                                      Thanks Trebo!
                                      When i use the calc i get dgm8mqf1 as your master password.

                                      Worth a try.
                                      Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                                      Comment


                                        #20
                                        Re: Shorting a EEPROM chip

                                        Also, depending on the ending to your service tag it could also be

                                        zbdg6f9m

                                        or

                                        Sjj2D54gsrx30k6z <<<<<Some caps letters in that one. First S and D!

                                        Not sure if it is case sensitive?

                                        Good luck.
                                        Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                                        Comment

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