How did people manage to desolder the old lcd from the board? Did you just use an electric desoldering iron gun? I don’t think I’m able to get the solder off clean enough to remove the lcd screen.
Hiya!
It's been a hot minute so I don't remember exactly but I'll try and recall the process (someone here can probably chime in with corrections if they spot issues):
- I bought a new LCD module: "1602 BLUE LCD 16x2 HD44780 with IIC I2C Serial Interface Adapter Module Display"
- The module came with a controller already on it, which I then removed so it matched up with the original.
- To remove the original, I desoldered the 16 pins from their corresponding places on the bottom of the unit (the ones which you can see at the top left of the module). I then clipped the plastic spacers, and pulled it free. In the process, I damaged the base PCB by pulling up one of the pads, because I failed to properly and fully desolder it before forcing the unit free.
- I seated the new module in its place, and soldered as normal.
- I then soldered in a bodge wire to connect a pad I damaged in the process to its respective spot on the board.
For desoldering in general, I use a Hakko FR-301 desoldering tool when space permits. For tighter spaces, a bit of braided copper wick. When solder is cemented in and just not pulling up I'll flow in some fresh stuff on top, and that sometimes helps ease the old stuff out. In situations where particularly stubborn solder has blocked a pad, but there is no corresponding part on the pad, I'll sometimes use a pin drill with a bit just slightly smaller than the pad. But this tends to be a last resort for me, since it can result in damage to the pad if done incorrectly.
In the case of my unit, inexperience lead to damaging the base PCB that the LCD module was attached to. I should have spent more time properly desoldering the pins from the bottom to ensure they would pull up freely. From what I recall, the solder on the pins on the board was a little stubborn, and rather than taking my time to fully clean the one or two pads that were stuck, I got frustrated and decided to YOLO it out (resulting in the pulled pad).
Now that I've got the part in hand again and am looking at it, though, I wonder if I couldn't have simply desoldered it from the top and lifted it free without the pins- sparing myself much of the headache. If I were doing it again, I'd probably do that instead
TL;DR:
See the 16 pads on the top left of the LCD module? Desolder those (using a desoldering gun or copper wick, or whatever method works for you). Remove the plastic spacers- I cut them since I had replacements handy, but they can be removed without the need for that if you like. Lift the module free of the pins. Put the new module in its place and solder.
