HP65 display issue

[GreyUser]

Soldering requires raising the temperature of the connection to point the solder liquifies and can be vacuumed away. Given the thermal mass of the tip being used and the required final temperature, it becomes a question of time. How long does it take to reach the required temperature? The absolute minimum time required is the goal.

Heatsinks create the opposite of the desired action as they require the application of a higher heat, for longer times than would normally be required to overcome the added mass of the heatsink. Anything that is removing heat from your connection requires you either use a higher tip temperature, applied for a longer time or a combination of both.

In this specific case, the thinner than normal FR-4 board, which heats faster than a thicker board, sets up the likely possibility of lifted pads. It’s the board that is at risk, not the component.