I soldered my first TQFP 100 package, an Altera MAX II EPM570 CPLD, on a PCB.
But I only found the "correct" way to solder (put flux on the pads and on the pins, melt some tin on a thin iron tip, then gently move the tip across the pads without touching the pins) on the fourth side, after several tries with the other three.
Blobs were forming on the pins; I tried using solder wick to remove them, but for some reason it didn't absorb absolutely anything. Even with the iron set to 420°C and pressing the tip for 10-20 seconds a few times. Then I read the advice to apply solder flux to the wick, and finally it started doing its job. So I managed to remove all the blobs.
This is how it looks now. East side went flawlessly, the other sides are repaired:
I'm concerned I've burnt the chip due to excessive heat. Here are my questions:
- Should I just desolder this chip and try again with another one?
- If I decide to keep it, can I verify that all the I/Os are still working before mounting all the other components? I can solder what's necessary to power it up and connect via JTAG. Reason I ask, is that I have a CPLD with a burnt I/O with everything else still functioning otherwise.