Rework, Modification, and Repair of Electronic Assemblies Flashcards
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Read the first 7 Rework, Modification, and Repair of Electronic Assemblies flashcards as text
When documenting a repair on a Class 3 assembly, which information is typically NOT required in the repair record?
Answer: The retail cost of the replacement component
Repair records for Class 3 assemblies require traceability data (technician, date, part ID) and repair descriptions, but the commercial cost of parts is not a required element.
Which type of solder wick is most effective for removing lead-free solder during rework?
Answer: No-clean flux-coated braid pre-wetted with additional flux
No-clean flux-coated braid pre-wetted with compatible flux ensures effective wicking of high-melting-point lead-free alloys without leaving harmful residues.
A technician must repair a delaminated area of a multilayer PCB. What is the first step before applying any repair material?
Answer: Bake the assembly to remove all moisture from the delaminated area
Baking removes residual moisture from the delaminated area, which is critical because trapped moisture will cause further delamination or void formation if epoxy is applied over it.
When performing a component addition (piggyback) modification on a PCB, what must be verified before attaching the additional component?
Answer: Mechanical clearance, thermal compatibility, and electrical impact on the circuit
Before piggybacking a component, the technician must verify there is adequate mechanical clearance, the assembly can handle additional thermal load, and the modification does not adversely affect circuit performance.
What is the correct procedure when a QFP gull-wing lead is broken flush at the package body during rework?
Answer: Declare the component unrepairable and replace the entire package
A lead broken flush at the package body cannot be reliably re-terminated; IPC-7711/7721 requires replacing the component in this scenario.
During hot-air BGA rework, the technician observes the component shifting laterally as solder liquefies. What should be done?
Answer: Immediately remove heat, allow solder to solidify, and restart with proper fixturing
Allowing the solder to re-solidify with the component misaligned and then restarting with proper fixturing prevents further misalignment and potential pad damage.
After completing a rework operation, IPC-7711/7721 recommends performing which final inspection step before returning the assembly to production?
Answer: Full inspection per IPC-A-610 acceptance criteria appropriate to the product class
After rework, a full inspection per IPC-A-610 acceptance criteria ensures the repaired assembly meets all quality and reliability requirements for its class.