Shorting a EEPROM chip

**2andrewd** · 09-29-2012, 01:04 PM

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.

**Peter9DO** · 09-29-2012, 08:48 PM

Re: Shorting a EEPROM chip

Originally posted by 2andrewd

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

**2andrewd** · 09-29-2012, 09:29 PM

Re: Shorting a EEPROM chip

read through this thread.

**Peter9DO** · 09-29-2012, 11:10 PM

Re: Shorting a EEPROM chip

Originally posted by 2andrewd

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

**2andrewd** · 09-30-2012, 02:33 AM

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.

**Peter9DO** · 09-30-2012, 05:00 AM

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.

**Peter9DO** · 09-30-2012, 05:49 AM

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

**vinceroger69** · 09-30-2012, 06:05 AM

Re: Shorting a EEPROM chip

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

**Peter9DO** · 09-30-2012, 06:27 AM

Re: Shorting a EEPROM chip

Service Tag# FWTHJ11
Express Service Tag# 34636179349

**vinceroger69** · 09-30-2012, 06:35 AM

Re: Shorting a EEPROM chip

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

**Peter9DO** · 09-30-2012, 06:50 AM

Re: Shorting a EEPROM chip

Originally posted by 2andrewd

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

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...

**ReverendJones** · 09-30-2012, 12:29 PM

Re: Shorting a EEPROM chip

Try Q5UQN8HQ as the password.

**heavymachines** · 09-30-2012, 03:21 PM

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...

**Peter9DO** · 09-30-2012, 06:07 PM

Re: Shorting a EEPROM chip

Originally posted by ReverendJones

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

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

**Peter9DO** · 09-30-2012, 06:17 PM

Re: Shorting a EEPROM chip

Is FloppyPack a company that makes BIOS software?

**trebo** · 10-01-2012, 02:09 AM

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

**Peter9DO** · 10-01-2012, 08:26 AM

Re: Shorting a EEPROM chip

Thanks Trebo!

**gilly1984** · 10-01-2012, 12:10 PM

Re: Shorting a EEPROM chip

Originally posted by Peter9DO

Thanks Trebo!

When i use the calc i get dgm8mqf1 as your master password.

Worth a try.

**gilly1984** · 10-01-2012, 12:20 PM

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.

Shorting a EEPROM chip

Shorting a EEPROM chip

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