The 1790 Digital is a generator-set controller. It is used on generator sets from Stadco, including the CD20, CD30 and CD40T4.
| Symptom | Cause | Remedy |
|---|---|---|
| Engine starts but the crank output does not turn off | The controller is not receiving a speed signal | Verify the Sensors -> Engine Speed -> Signal Source setting is set correctly; Verify the Timers -> Engine Logic -> RPM Disconnect setting is set correctly; Ensure the correct wiring to the controller. For magnetic pickup, Speed Sensing A and B terminals are used. For generator voltage, the AC voltage connections are used |
| High voltage either on no-load or with load | Check speed; Check that generator load is not capacitive (leading power factor) | |
| Low voltage no-load | Check speed; Check link 1-2 or external hand trimmer leads for continuity | |
| Low voltage on-load | Check speed; Check UFRO setting; Follow separate excitation procedure to check generator and AVR | |
| No voltage build-up obtained after field flashing | A fault exists in either the generator or the AVR circuits | Follow the SEPARATE EXCITATION PROCEDURE to check generator windings, rotating diodes and AVR |
| No voltage build-up when starting set | Check speed; Check residual voltage; Follow separate excitation test procedure to check generator | |
| Sender always displayed its lowest or highest value | The sender could either be open (not connected) or shorted to ground | Verify your connections and ensure the correct sender table is loaded |
| Unstable voltage either on no-load or with load | Check speed stability; Check stability setting |
Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.