Okay. I finally got around to fixing my two bad triacs (one on two different Lynx EX boards).
Here is what I have in my de-soldering arsenal: Radio Shack Bulb-type desoldering iron, Desoldering braid, hard metal pick tool (got this in a solder tool kit from the shack), needle-nose pliers, and rosin based flux (also from the shack).
Step one: Remove the board from the enclosure.
- Remove all connections (power and cords) from the board
- Unscrew the board from the enclosure (make sure to hold on to screws and risers you may have used previously)
- Carefully remove the board (make sure you take appropriate anti-static precautions)
Step two : Remove the heat sink from the PCB
- Unscrew all 16 Triacs from the heatsink. Take care to save each bolt and locknut in a safe place
- Unscrew the Heat sink from the PCB (two screws). Take care to save the screws, plastic riser, and plastic washer in a safe place
- Remove the Heat sink taking care not to get any heatsink compound on you or your clothing (that stuff is a mess!)
Step three : Remove bad Triac
- Use gentle force to rock the bad Triac back and forth until the legs snap off. Be careful not to move any of the neighboring Triacs
- Throw away the old Triac (so you don't confuse it with the new one!)
- Apply a bit of flux around the remaining three 'legs' that are left
- Use either a desoldering iron or desoldering braid to soak up all of the solder as possible. Remember to desolder both sides of the board (the original solder side and the side the triac body was sticking up from). The idea is to get as much of this clean as humanly possible. Work in 10 second phases to avoid any burning around the pads.
- Use the iron to heat up any residual solder on the leg and use the needle-nose pliers to pull each leg out. If you do this correctly you should have three clean holes where your triac once was (use a light and magnifying glass to check).
- If your holes are partially obstructed by solder, you can either try to remove more solder with the desoldering techniques or use a soldering pick (hard metal pick) to try to enlarge the hole manually. Keep at it until you can safely and easily push the new triac into place.
- Solder your new Triac in place
Step four : Reassemble the Heat Sink
Step five : Re-attach your PCB to the enclosure and re-attach all cords
Step six : Test to make sure your new Triac works!