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Use a hairdryer to heat up (soften) the coating under the eprom.
Just lift the eprom up slightly and direct the hot air under it and the coating will let go.

A heatergun for paint works even better, but requires skill or you'd possibly melt the flatcable or components near the eprom.
I sometimes completely unsolder the eprom using the heatergun and clean the pin holes after removal

Guilt-Toy wrote:any ways around doing it without a de-soilder gun? resources are a bit limited here...

Just to answer this question, it CAN be done without a de-solder gun, but obviously a de-solder gun is the best (and most expensive) method of removing it. However, when I was at uni and doing stuff in my own time I had limited funds and therefor a de-soldering gun was out of the question back then.

Basically you can do it with a soldering iron (pref temp controlled, but not essential) and some de-solder wick, AVOID those de-solder pumps like the plaugue! Unless it's a proper vacume pump on a de-solder gun, it's gonna be useless!

1. Clean off conformal coating with acetone and a brush

2. Apply some liquid flux using a flux pen or similar to help create a good heat bridge

3. Line up the de-solder wick to the pin you want to de-solder

4. Apply the soldering iron to the back of the wick and hold for 1-2 seconds

5. Once solder has been drawn into the wick, pull it away while still holding it iron on it! If you remove the iron first, then the wick will just end up being soldered to the part, so keep applying heat as you pull the wick away to ensure it comes away cleanly.

6. Repeat on other pins.

I have personally done this MANY, MANY, MANY times on various electronic devices from home made things, to games consoles, to the odd ECU when my de-solder gun was not available. De-solder gun does make things a bit easier, but with a bit of practice, I actually find using a good temp controlled iron and de-solder wick sometimes a little quicker than the de-solder gun.

Yep, you can get away with solder wick. The key to avoiding damage is to not leave the heat there too long. As you said, use some flux so you get a good heat bridge, let the solder wick suck the solder up and then get outta there!

The bond between the copper and the fibreglass laminate on a board has a limited ability to handle heat. So the less time you spend at soldering temperature the better. I like to keep it under about 2 seconds max per joint. So about 1 second to de-solder and 1 second to re-solder. In practice you can usually get away with more than this but try not to linger too long.

The other thing is pressure. Try not to push on the pads with the iron/sodlerwick. This will cause the pads to lift very quickly. I've seen some people grind away thinking that if they push down hard then they'll get better heat transfer. The key is to use a soft touch and use flux/solder to form the heat bridge - not pressure.

PL

PL wrote:The other thing is pressure. Try not to push on the pads with the iron/sodlerwick. This will cause the pads to lift very quickly. I've seen some people grind away thinking that if they push down hard then they'll get better heat transfer. The key is to use a soft touch and use flux/solder to form the heat bridge - not pressure.

PL

Yup, pressure is very important! Need to make sure not to push down hard and to just gently hold the iron and let the heat do all the work. Putting lots of pressure on it will just cause damage.