Hi all, Basically I have an SMD EEPROM (24C04) on a circuit board that I would like to extract and put onto a programmer to get the data. But what is the correct / proper / safest way to extract an SMD component? Obviously I could just de-solder the legs but I am very worried about messing it up! I cannot lose the data. Any advice please? Thanks.
what device is the EEPROM in? and what package is it? if it is SO8 (or SOIC-8, same thing really...) then desoldering it may be possible. But desoldering it, putting it in a programmer, and putting it back could be very stressful to the chip. If you *NEED* the data and dont need the device. Then simply cut the data traces, and solder on your own wires to the chip leads. Solid core eithernet wire works fine for this, or even better would be 30 awg wire wrapping wire. It could even be possible to repair the device afterwards my scraping off some of the solder mask and re-joining the traces you cut. If you can control the data rate of the programmer, slow it down as much as possible. and make the length of the wires as short as possible to the programmer. SMD devices can be pretty tough... I baked the heck out of a soic-8 pwm controller chip I was using for my battery powered battery charger. Put it on, overloaded it, desoldered it with a normal iron, (just a big blob on both sides, heat one, then heat the other, pull it up with tweasers) tested the board, then soldered it back on again, and it worked fine. But I had a spare in case I did frag it. You dont have a spare, so I would definitely solder leads onto the chip for the programmer.
Nice link, thanks a lot. Looks like a hot-air gun is the answer? Which I do not have one and very expensive to buy Yes it is indeed SO8... Basically what I want to do, is to remove the 24C04 SMD from the board, read its data, then put a ZIP socket or similar put in, and use a "plug in" type 24C04 with the old chip's data, so in the future I can read and write to the chip easily. May be it is not a DIY job afterall then?
What is the device? Just so I can get an idea on the size you're working with. What sort of programmer are you using? a JDM programmer?
Device... it is a 24C04 EEPROM SMD version, or am I understanding your question correctly? Don't know what programmer I'll be working with, because I haven't got one yet. And sorry I don't know what a JDM is... I am just planning to buy a cheap one from eBay, or buy one next time I go to Hong Kong.
Sorry, I meant what was the chip in? like a clock, or game or something... The JDM is a cheap serial programmer that works off the com port on a PC. You can typically build one for less than $5 depending on your sources. Ive mainly seen it used on PICs but if you use it with ICprog (a program) I believe you can use it to read/write serial EEPROMs. I'd be pretty leery about trying to desolder the chip then get the information off. It just wouldnt surprise me that if during the process of desolding (the chip being above specified temps for more then a few seconds) that a few bits got corrupted. Though it wouldnt surprise me if it wasnt, why risk it. From what it sounds like, you want to take off the SOIC chip, and put in a socket so you can plug in a DIP EEPROM at your own leisure. This will require modifying the board anyway, so I would try to read the chip without desoldering it. Besides, once you have it free, you need a SOIC socket to hold it to read it. All the SOIC ZIF sockets ive seen have been pretty pricy. Solder wires onto the legs of the chip, and then use a knife to cut the trace, just past the leg of the chip. Then you can wire it to your programmer, read it, desolder the original chip using your iron an some blobs of solder, and then put in your socket and new EEPROM. Even better would be to just re-program the EEPROM on the board, but you would need to be able to power up the EEPROM without powering up its master which controls the EEPROM, possibly a jumper on the power line to the EEPROM? It
you could try using wick or a solder-sucker... or 8 soldering irons at the same time with 4 of your friends...
