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I am trying to download the contents of a ROM chip following this tutorial however the chip is surface mounted and I can't remove it to put it in a breadboard.

I don't want to solder wires to the chip but there has to be a way of attaching them other than holding loose wires to the pins.

Specifically This chip

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While there are ways to clip onto SMT ICs, you're almost certainly going to need to disconnect it from the board anyways, so it's not connected to other devices which might also be trying to send signals to the ROM. Basically, you have to remove the chip from the board no matter what. –  Connor Wolf Dec 25 '12 at 9:46
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It would help to know which chip or which smd size (or just a picture) to give the best suggestions. Aside from that, as Fake Name said, without removing it from the board, you can have two problems. One, connecting VCC will power most of the board. Two, there is a possibility that even if you detach vcc and gnd, that the board might still get powered. –  Passerby Dec 25 '12 at 10:21
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3 Answers

up vote 3 down vote accepted

Update

Here is a good list of micro grabbers/test clips (or whatever you want to call them): http://www.jameco.com/jameco/products/prodds/684481-ds01.pdf


As mentioned, it would be helpful if we knew the board and the chip. But without that information here is what I recommend.

First off, you need to buy some micro grabbers. These will allow you to connect to individual pins on medium sized surface mount components (usually around .5mm pitch). They look like this:

Micro grabbermicrograbber

Now if you power to board and listen in on the bus, you can gather needed information like i2c address, etc. and see how active it is. From here you may be able to dump the memory without any ill effects. Otherwise you can use my method for removing surface mount parts to only remove the data communication pins. Place something non-conductive between the pin and the pcb board so it won't make contact. Then read out the memory like you planned. This will make it much easier for you to resolder the two or so pins you removed back on, and is easier on the chip than completely removing it and trying to power it, etc.

If you don't have or want to get micro-grabbers, you can very carefully place a ~22 gauge solid wire under the pin but on top of the non-conductive material, so that the wire is making contact with the pin. This will be hard to keep from disconnecting but with a bit of work you will get the hang of it.

If at all possible, I would stay away from soldering wires directly to the pins!

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Those micro-grabbers look awesome. Didn't know they existed –  Darcys22 Dec 26 '12 at 7:48
    
@Darcys22 yah they come in handy! You can get 5 for $5 at sparkfun, although they look a bit bigger than the ones I have. –  Garrett Fogerlie Dec 26 '12 at 8:40
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The datasheet you linked to shows only big fat packages like DIP and SOIC. It should be easy to solder wires to those pins. You say you don't want to but don't give any reason, so this is still your best option.

I would use thin "wire wrap" wire, which is around 30 or 32 guage if I remember right. Such wires won't be strong, but good enough to talk to the chip to dump its contents. Then you unsolder the wires when done.

"DIP clips" and the like can work, but in my experience they are also flaky. When it's not working, you won't know whether that is due to firmware, wrong connections, or the connections you did make aren't working. By soldering, you at least eliminate one of these three.

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Lack of soldering experience mostly, haven't worked on anything nearly this small before and confident I would ruin the board –  Darcys22 Dec 26 '12 at 7:52
    
@Darc: That can be a problem for parts with tight pin pitch, but this part has big fat pins. Those clip thingies may sound nice in principal, but in my experience you waste a lot of time chasing bad connections. –  Olin Lathrop Dec 26 '12 at 14:49
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Best bet is to find the data lines that are on the board and can be tapped to get the right data. Note that depending on how you connect to it, the circuit in which it sits might interfere with reading the data.

If you do finally decide that desoldering is OK for you , then several companies make Sockets for surface mount devices. Note that some of these can be a bit expensive but are worth it.

See:

3M Sockets

Ebay listing for sockets - Seems to be inexpensive

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