The chip has 8 leads, can comes in a variety of shapes and sizes. It is part of a larger family of serial storage chips which includes the 24LC02, 24C04, 24C06, and 24C16. (The last 2 numbers in the name refer to the number of Kilo-Bits that the chip can store.)
The one which was used in the demonstration was a ceramic encased surface mount DIP chip which is based on the design shown on the left.
I have seen and heard about people who offer to sell new blank 24C02 chips to people, so they can unsolder their old one, and then re-solder the new one in. This will work, if all goes well and the new chip has not been damaged. These people, and their websites, attempt to convince anyone needing to clear a password on particular laptop models that they have only one recourse. That they must purchase one of these chips, and either attempt to solder it in, or pay for a costly chip soldering / replacement service.
These people charge exorbitant prices. Someone I know personally paid $50 for one of these chips. But I have found that they are available from reputable electronics firms for much lower prices. I have seen them being sold (The same chips) for between $2.50 and $15.00 apiece, usually around $5.00. There was even one firm that was selling them (wholesale) for 750 (If you buy them by the thousand.) At an average cost to them of about $5.00 for the chip, 370 for a stamp, and a few cents for an envelope (usually they send it to you in a normal postal envelope) that's about 6 bucks. So, how much profit are these people actually making? You do the math.
Another factor here is where the person ordering the chip has to solder it in themselves. Soldering is not that difficult in general, and plenty of people can solder normal electronic components. But, this is a little different. This is a surface mount component. Surface mount components were designed to be soldered on to a circuit board by a machine using a special process, not by hand. This chip requires solder contacts of less than a millimeter, with less than a millimeter between each; and 4 on each side. It has to be lined up pretty precisely; surface mount components are held to the surface of the board by solder welds instead of having legs that stick through holes in the board. It requires excellent eyesight, and a very steady hand.
And, the primary risk factor in hand soldering surface mount components is Heat. When surface mount component boards are manufactured, a machine applies the exact amount of solder to each leg, and solders all the legs at the precisely the same time, by heating the contacts at exactly the right temperature for exactly the right amount of time needed to complete the soldering. This is very different from hand soldering, where one leg is soldered at a time, with a soldering iron who's temperature is know to be precisely: pretty damn hot!; until the solder weld looks like it's good. With the short distances between where the leg (which is made of metal and conducts heat) is soldered and where it runs into the silicon chip, the chip could easily be damaged. Even I, who consider myself to be rather good at soldering, wouldn't consider even trying something like this without some special equipment.
So, the service these people are offering (other than keeping their supplier a secret) is to let you pay them a nice heap of money, so that you can wait for the chip to come in the mail. Then you can try unsoldering the chip and replacing it by hand, possibly ending up with something that looks like the microchip in this picture or worse:
Now, if someone really does need a chip, (If this pertains to you, I'll bet you wish you hadn't been so hasty) one can obviously be ordered from a reputable business. But, this may not be necessary!
The 24C02 and related / compatible chips are all around you. If you work with computers, then they are right under your nose. If you have a DIMM memory module available, look at what it says on the small chip in the upper right hand corner. 24C02, 24LC02, 24LWC02; something like that?
That's right! There are 24C02's everywhere. What? You had been thinking that they had to be ordered from a special website, because they were specially made just for your laptop? Heck, no. They are everywhere, most easily found on DIMM's. On a DIMM they store the information about the manufacturer, size, speed, type, error checking capability, and even how the rows and columns of memory are ordered and addressed.
But they are not just on DIMM's. Remember, these chips store information which can be read by whatever they are in. Also, they are a rather common, chip that is well known and familiar to electronic engineers. It is also easy to use, and has many flexible applications. And it's cheap! (as far as chips go) It's not surprising that they would be modems, LAN cards, etc... (and laptops)
I saw one on a DVD decoder card, (hmm...) and I heard about a similar chip (24C16) being in a satellite receiver box. (I wonder what they could be doing in such devices.) (Not to mention that many smart cards [like the ones that go in satellite boxes] have a 24c02 or similar chip embedded inside of them)
I don't know for sure, but I'm guessing that; the modem uses the chip for manufacturer, speed, and Plug and Play information; and the LAN card for PnP and / or NIC number. We already know what the laptop uses it for. I won't, and probably don't have to, speculate about what it's used for in either the DVD decoder or Satellite box.
Well, there you have it: The demonstration and some info on the chip, and stuff. If anyone has to have a new chip, one can probably be scraped off of a bad DIMM stick. (It's best to expose such components to as little heat as possible. Also, it is possible to hand solder these chips if necessary, or if you just feel like it. But it is difficult. Check out what one guy did to the chip on one of his DIMM's: LM75 Temperature sensor in DIMM
Naturally, this guy knew what he was doing; but it just goes to show that there are a lot of possibilities out there. So don't think any challenge or knowledge is beyond your reach, because there's always helping hands out there - somewhere.
The information in the chip can be read / written with a special device called an EEPROM reader or programmer; or a PICprog (Programable Integrated Circuit programmer.)
Devices like these can be purchased for around $100 or less, and [with a some time and quite a bit of reading for those new to electronics or programming] used to read, write, or manipulate the information in EEPROM chips. It is also possible to build your own circuit with a little know how, the right chips, and a few hobby electronics supplies. There are a number of places on the internet where these products or materials can be found; as well as instructions on how to build or use them.
I have heard that chips in Dell laptops contain the password, and 2 tags in standard IBM type Scancode format (there are different standard scancode formats.) I have not verified this yet, but hope to get a PIC reader and check this sort of thing out sometime soon.
Scancode is a code (binary byte or word) sent by the keyboard to the computer. The computer then uses this code to interpert what the user is doing on they keyboard. A certian code is sent each time a key is pressed and another when it is released. This is how key combinations such as Ctrl + Alt + Del can be pressed at the same time without conflicting with each other's signals.
Was this article helpful?
Read how to maintain and repair any desktop and laptop computer. This Ebook has articles with photos and videos that show detailed step by step pc repair and maintenance procedures. There are many links to online videos that explain how you can build, maintain, speed up, clean, and repair your computer yourself. Put the money that you were going to pay the PC Tech in your own pocket.