Best way to desolder and remove a 24-pin SMD IC?

[wilykat]

I need to remove and replace an SMD, a 2kx8 SRAM in 24 pin package. The leads I believe are 0.05 inch pitch. I don't have hot air station as I never needed to remove anything beyond SMD resistor and transistors. 2 and 3 leads were easy to remove with iron and tweezer.

I have tried desoldering braid but it doesn't wick up at all, I think the IC were soldered in with solder paste and not regular solder, those seems to cause me trouble. The other desoldering tool I have is vacuum type and it only works with through hold desoldering. I had considered trying to wedge in something under the IC and heating up leads to soften the solder but I risk popping up traces.

So any idea how can I desolder and remove the IC safely? THe soldering iron I use is a variable temp and uses Hakko type tip, the SMD IC attachment I found were for different iron that doesn't use heating rod inside the iron like Hakko and clones.

 

[ClydeCrashKop]

Can you clip all the pins off the IC? Then you can work on them a few at a time. If you add solder with a lower melting temperature it helps.

 

[Nigel Goodwin]

As above, but use a sharp knife (scalpel etc.) to cut the leads against the body of the chip, then use a soldering iron to remove all the pins from the board - adding a blob of solder across all the pins helps.

Lastly remove the chip, this may be glued down, but a sharp 'tap' using a screwdriver as a chisel pops it off the board.

 

[ClydeCrashKop]

Professional SMT Soldering: Hand Soldering Techniques ...

This is a neat trick
How to remove smd chip without hot air

 

[jpanhalt]

I agree on clipping the leads as the easiest way.

If you are faced with a similar situation and need to preserve the chip, I have used ChipQuik solder. It is a very low melting alloy with bismuth and indium. You flood the pins with it, then use solder braid to suck it up. That produces a low melting alloy at the pins. ChipQuik itself melts at 136 ºF (58°C) (https://www.chipquik.com/datasheets/SMD1.pdf ), so an ordinary hair dryer or heat lamp will melt it. After removal, suck up the excess with wick and resolder as usual.

John

 

[wilykat]

I didn't want to use knife, I run the risk of slipping and cutting trace or my fingers. My smallest wire cutter can't quite fit in there and when I tried the video trick above, the clip melted all the solder but the chip wouldn't budge even with force. I ended up doing the dentist pick trick, heated and lifted one pin at a time. When all 24 pins were lifted, it still wouldn't come off.

I ended up tapping the screwdriver and it finally popped off, someone used quite a bit of glue to hold the chip down. I cleaned the excess solder. and checking under magnifying glass and my meter all 24 pins are still intact and still connected so no trace was severed or pad lifted. I still have to clean up flux and install the new chip.