NIStune Soldering - Manual (Page 8)

De-soldering
Always clean the tip using a damp sponge. This may need to be done several times during the job.
Feed solder in when using a de-solder gun to form a heat bridge - just like when soldering. This will help
transfer heat into the joint effectively.
Only just touch the solder pad with the tip - don't push down on the pad!
Stir in a circular motion once solder is melted - moving the pin around to lossen it.
Around 3 seconds of heat max - extra heat on GND/power pins.
Check that all solder is being removed
When removing ROM chips, give pins a push with small blade screwdriver each side to make sure they are
loose.
May need to heat Power/GND from both sides at once.
Gently lever the chip out - don't lever it out if some pins are still soldered. You'll get the chip out no problem
but you may pull the barrel out of the hole. If it's a multilayer board (most are) then you'll have an open circuit
and the ECU will not operate correctly. Or at all.
Clean pads both sides with acetone and cotton bud once chip is out.