HL-7800 Easily Damaged By Soldering?

I am mounting the HL-7800 using low temperature solder (138 C melting point). My technique is, I quickly tin the module pads and PCB pads with small, even height solder bumps. I place the module over the PCB. I heat from the underside of the PCB with a heat gun until the module settles flat, and help by very lightly tapping on top of the module. I stop when the module settles flat. The first prototype worked well.

On a second revision of the PCB a second module communicated but would not connect (+CREG=0). I discovered the RF out pin was open. Normally it should measure close to zero ohms. I removed the module and verified the open was inside the module.

I decided to move the first module to the newer PCB. After verifying the RF out continuity on the first prototype, I removed that module (it was also low temperature soldered), and put it on the newer PCB. Now it doesn’t work in exactly the same way. Removing it, it also has an open RF pin.

I have been working with surface mount modules for several years this way. I have reused other modules many times with success. I have never lost a module due to my soldering method. This is the first module that is so easily being damaged by soldering temperature, and regarding a specific pin. I am uncertain how this module can withstand ordinary production soldering.


Your production process is not detailed too much but we have not had any reports of failures from customers generically if they follow the customer process guide lines as per the link below.