Electrical unit passes only after repeated tests
Hold the unit and preserve its original failed result. Have a competent specialist investigate the connections, test settings and product before authorising any repair. Record every retest separately and release only after the failure is explained and the agreed checks are complete. Cambridge China Bridge can coordinate the factory investigation.
Hold the unit and preserve the failed result
Treat a pass after repeated attempts as an unresolved finding. Label and segregate the unit, pause its shipment approval and ask the factory to retain the original test file. Keep the unit identity, measured result, acceptance limit, operator, date, instrument identity and photographs of the setup. Preserve failed and aborted attempts alongside successful ones.
Ask what happened between attempts, including reconnecting leads, moving the unit, changing settings or opening the enclosure. Do not accept a replacement report showing only the final pass. For the wider response to a failed production sample, see production sample safety-test failures.
Separate setup faults from product faults
Ask a competent test specialist to compare the recorded setup with the agreed product test method. Check lead condition, probe contact, fixtures, connection points, equipment status, selected test programme, limits, duration and product operating state. HSE guidance says people working on electrical equipment or systems should be competent for the task.
Investigate loose terminals, earth connections, cable routing and intermittent contacts without assuming the fixture caused the failure. Photograph the condition before disturbing it. Record each change and its reason. Do not weaken limits or bypass a safety check to obtain a pass. For production-line controls, see validating a factory's automated final test.
Authorise repair before work starts
Ask for a written fault explanation and proposed repair covering the affected parts, workmanship, responsible technician and checks afterwards. Agree who may authorise the work. Require that approval before the factory repairs the unit or substitutes components. Have the specialist arrange safe isolation and handling; buyers should not troubleshoot exposed electrical parts themselves.
Keep repair records linked to the original failed unit. Include photographs before and after work, replaced-part identities and the technician's findings. If the proposal changes the design, materials or software, seek a separate technical review before approving it. A repaired sample also needs to remain distinguishable from untouched production stock.
Record retests as separate events
Agree the retest method with the specialist before testing resumes. Keep the original failure unchanged and create a separate record for each subsequent attempt, linked to the same unit. Identify whether it followed a setup correction, repair or no change. Include the settings, measured results, operator and outcome, including any further failure.
Ask the specialist which related checks the repair may have affected and whether repeated electrical stress could have damaged the unit. Keep diagnostic trials distinct from acceptance tests. The final report should explain the sequence and why the result is acceptable, rather than simply stating that the unit eventually passed.
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Decide whether the batch can be released
Ask whether the cause could affect other units sharing components, assembly methods or test equipment. If a fixture fault is confirmed, identify stock tested with that fixture and agree how to reassess it. If a product fault is confirmed, agree containment and corrective action across the affected stock. An unexplained intermittent failure should remain open.
Require a named buyer approval supported by the investigation, authorised repair record and separate retest results before lifting the shipment hold. For evidence beyond the repaired unit, see closing supplier corrective action. Cambridge China Bridge's staff in China can request these records and coordinate factory follow-up.
Frequently asked questions
Can I accept an electrical unit that passes on retest?
Keep it on hold until the original failure is explained and the agreed checks are complete. A later pass alone does not resolve an intermittent fault.
Should the factory delete the failed test result?
No. Ask it to preserve the original result and record every later attempt separately, with the changes made between attempts.
What if the test lead caused the failure?
Request evidence identifying the connection problem, the correction and the subsequent results. Review other stock tested with the affected setup.
Who should approve repair and shipment?
Agree repair authority before work starts. Have the specialist assess the technical evidence, then obtain the named buyer's shipment approval.