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. | 1. Verify the Sensors -> Engine Speed -> Signal Source setting is set correctly. 2. Verify the Timers -> Engine Logic -> RPM Disconnect setting is set correctly. 3. 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) | 1. Check speed. 2. Check that generator load is not capacitive (leading power factor). | |
| Low voltage (no-load) | 1. Check speed. 2. Check link 1-2 or external hand trimmer leads for continuity. | |
| Low voltage (on-load) | 1. Check speed. 2. Check UFRO setting. 3. Follow separate excitation procedure to check generator and AVR. | |
| No voltage build-up when starting set | 1. Check speed 2. Check residual voltage. 3. 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) | 1. Check speed stability 2. 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.