Fagor alarm E904: RPS: Phase missing in the auxiliary power supply line
DDS drive display code (seven-segment; PS/XPS/RPS power supplies) · Fagor PS/XPS/RPS
What it means
The three phases are not being detected on the dedicated line feeding the RPS integrated auxiliary power supply (which powers control circuits and the 24 V system). Check the connections of that auxiliary tap specifically — the main power phases can be fine while this one is not.
Likely causes
- fuse protecting the auxiliary transformer tap blown
- auxiliary line terminations loose
- auxiliary winding/transformer inside RPS failed
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- Request a quote →
Auxiliary circuit fuses per RPS schematic
component · Common cause
Need the part urgently?
Send us alarm E904 with your machine details — typical RFQ turnaround is 24–48h.