Troubleshooting for high or low chopper voltage
Diagnostic codes 779, 780, 781
Diagnostic codes 779 – 781 occur when the chopper voltage is not in the permitted voltage range.
Symptoms
| Code | Symptoms | XPR® models | XPR action | Code cancels with... |
|---|---|---|---|---|
| 779 | The Chopper 1 15 V bus is out of range (less than 13 V or more than 17 V). | All models | End of cycle |
|
| 780 | The Chopper 2 15 V bus is out of range (less than 13 V or more than 17 V). | XPR300®, XPR460® | ||
| 781 | The Chopper 3 15 V bus is out of range (less than 13 V or more than 17 V). | XPR460 |
Corrective action
- Examine the 24 VDC on connector J2, pin 1 and pin 2 for the chopper that gives the diagnostic code.
- If there is no 24 VDC, examine the J2 wiring on the chopper.
- Tighten loose connections, if found.
- If you measure 24 VDC, replace the chopper assembly.