When soldering the wires with the terminal, there may have flux residue on the wire or terminals. Top-cable also follow IPC-A-620 spec to control it.
Flux residue may be present if it is no-clean flux residue that is not intended to be cleaned. (No illustrations)
Target - Class 1,2,3
• No visible flux residue.
Acceptable - Class 1
Process Indicator - Class 2,3
• Flux residue does not inhibit visual inspection.
• Flux residue does not inhibit access to test points of the assembly.
Acceptable - Class 1
Defect - Class 2,3
• Flux residue on, around, or bridging between noncommon conductors.
• Flux residue inhibits visual inspection.
• Flux residue inhibits access to test points of the assembly.
Defect - Class 1,2,3
• Wet, tacky, or excessive flux residues that may spread onto other surfaces.
• No-clean flux residue on any electrical mating surface that inhibits electrical connection
