Quality / Service Technical Reference
UTY-CDPXZC Reported Factory Mis-Wiring - D61 Damage Investigation
Investigation found D61 damage but did not confirm factory mis-wiring
A quality assurance investigation was completed after a report that a UTY-CDPXZC had been wired incorrectly at the factory. The returned sample showed damage to D61, however the investigation did not identify evidence supporting the reported factory mis-wiring.
Affected Unit
| Product | UTY-CDPXZC |
| Serial number | T001261 |
| Reported issue | Customer-installed unit was reported as having been wired incorrectly at the factory |
Sample Unit Analysis
The returned sample was checked using the factory checker.
Finding: The factory checker returned an NG result. D61 was damaged, while no damage was identified on the other components referenced in the report.
D61 was found to be cracked.
- When D61 was removed and the electrical circuit was connected, the unit operated correctly.
- D61 is used as protection against a 12 V surge.
- The unit is capable of operating even with D61 removed.
Circuit and Wiring Diagram Review
The PCB circuit and wiring diagrams were reviewed to determine whether the reported wiring error could have caused the observed D61 damage.
| Item | Finding |
|---|---|
| Circuit affected by the reported terminal mis-wiring | CN5 |
| Circuit connected to damaged D61 | CN6 |
Conclusion from circuit review: The reported terminal mis-wiring would affect CN5, whereas the damaged D61 is connected to CN6. Based on the circuit review, the reported mis-wiring was therefore not considered capable of causing the D61 damage observed.
Factory Process Confirmation
The manufacturing process at FGT was reviewed.
- After all wiring is connected, FGT performs an energisation confirmation check.
- The check verifies both the wiring condition and software contents.
- After testing, the wiring insertion condition is confirmed and marked.
- This checking process is carried out on all products.
Replication Test
FGT repeated the energisation confirmation process with the wiring intentionally mis-connected in the same way described in the Australian report.
Result: The checking software detected the mis-wiring during the factory energisation confirmation process.
This demonstrated that if the same mis-wiring occurred during factory assembly, it would be expected to be detected during the standard production check.
Investigation Conclusion
FGL was unable to determine the actual cause of the D61 damage.
The investigation established that:
- D61 was damaged and cracked.
- The unit operated when D61 was removed.
- The reported mis-wiring affected a different circuit from D61.
- The factory production test was able to detect the reported mis-wiring condition.
- No confirmed root cause for the D61 damage was identified.
Final finding: The investigation did not confirm that the unit had been mis-wired at the factory, and no conclusive cause of the D61 failure was established.
Service Guidance
- If a similar UTY-CDPXZC issue is reported, record the exact wiring configuration before making any changes.
- Inspect the PCB for visible damage, with particular attention to D61.
- Confirm whether any reported wiring error affects CN5, CN6 or another circuit.
- Photograph the terminal wiring and PCB condition before repair.
- Retain the damaged PCB where practical for further analysis.
- Do not attribute D61 damage to factory mis-wiring without evidence that the wiring condition could electrically affect the D61/CN6 circuit.
Information to Collect if the Issue Reoccurs
| Item | Details Required |
|---|---|
| Unit identification | Full product model and serial number |
| Wiring condition | Clear photos showing all relevant terminal connections before disturbance |
| PCB condition | Close-up photographs of D61, CN5, CN6 and surrounding components |
| Fault symptoms | Exact operating symptom, error indication and circumstances of failure |
| Component retention | Retain the affected PCB for analysis where practical |
Safety: Isolate electrical supply before inspecting or altering controller wiring or PCB connections. Electrical diagnosis and repairs must only be completed by suitably qualified personnel.