Now the moment I’ve been waiting for…soldering with a stencil, solder paste and my hot air gun. I had the solder paste stored in my refrigerator in a cooling bag. I had taken it out to get to room temperature a few hours before.
The first thing I did was to tape down the stencil.
Now, spread the solder…
Peel off the stencil…
OOPS! Way too much solder paste This was my problem when I was using a solder iron. I finally figured out that I needed far less solder than I thought. I haven’t done stenciling before…but I am assuming reflow will suck the solder up. OK, I’m hoping.
Placed the parts with an attempt to make sure the diodes were placed in the right direction.
TBD: picture of diode next to schematic picture with flow. next to pcbnew picture.
I set the hot air gun at 249˚C and air at level 4. I used the bigger of the tips I could find.
Definitely too much solder paste. This is especially true with the MCP3901. Using a magnifying lens, I could only find the MCP3901 with shorted pins.
It was easy to remove excess solder with solder wick on one side. However, the other side became more difficult than I imagined it should.
What added to this was a few of the pins were bent together! Not sure how I did that. Definitely points to being more careful with this chip. I removed the MCP3901
Before replacing, I tried connecting wires to the power jack – due to my screw up in drawing the footprint (see this post). Alas, there was not enough exposed copper on the PCB to attach the wires. Given that I can’t get power to the PCB, I can’t test. Drat.
Staying calm, the next move is to revisit the schematic and layout and update the power jack footprint as well as double check the circuits.