A colleague asked me for information about the reliability of capped vias in pads:

1)  How many allowed repairs?  

2)  Is it acceptable to hand solder wire lead components on those pads?

3)  How many allowed repairs are allowed for hand soldered component leads on thes pads?

4)  What is the recommended soldering iron tip temperature?  (for lead-free and tin/lead solders)

5)  Is the solder tip "touch up" time controlled well enough by the average repair technican when done manually to be acceptable or is only reflow soldering recommended (no rework)?

6)  Is the touch up time more variable, longer, when the solder is Lead Free?  (I would say yes it is and we only use eutectic tin/lead solder on COTS lead-free boards when we do a repair)

7)  Are there any restrictions on placing a via in a pad if the component leads are hand soldered to this pad?


Bob Landman
H&L Instruments, LLC



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