Technical Documentation, Quality Control and Customer Support
Domain 9: Technical Documentation, Quality Control and Customer Support
This domain tests schematics, BOMs, service records, revision control, inspection standards, and customer communication. The exam looks for traceability and evidence, not verbal assurances.
Core rules
- Documents must match revision: schematic, BOM, assembly drawing, and firmware version. Record serial numbers and measured values in service reports.
- A BOM lists reference designator, value, tolerance, package, and quantity. A substitute part needs electrical and mechanical approval, not just a similar value.
- QC uses defined criteria: visual inspection, AOI, functional test, and possibly in-circuit test. IPC-A-610 classes define acceptance levels; do not mix classes.
- Customer support: confirm the fault, explain options and costs, obtain approval, protect data, and state warranty terms. Never promise a repair outcome before diagnosis.
- Close the loop: record root cause, corrective action, and returned parts. Use that data to improve assembly or supplier quality.
Worked example
A repair record shows R14 marked 10 kΩ on the schematic but the BOM lists 1 kΩ, revision C. The board is revision C. The correct action is to query engineering, not to fit either part blindly. If revision C intentionally changed the value, update the schematic and service manual; if the BOM is wrong, raise a document change. The reasoning is that a value mismatch can be a design change or a documentation error, and only revision control distinguishes them.
Traps
- Repairing to an outdated schematic.
- Accepting a verbal customer approval for extra cost.
- Recording OK instead of actual measurements.
- Using a substitute capacitor with the same capacitance but a lower voltage rating.
- Discussing a customer's data or fault publicly.