text: <s>[INST] Ultra 3000i E55 fault Ultra 3000i E55 fault.when power on/off ,it wii show E55 error code. [/INST] Two main possible reasons: Personality EEprom Data Corruption, due to noise - not field fixable, you must return for repair (prevention is possible, verify proper shielding and grounding) If you have a small unit (.5kw, 1kw and 2kw) problem could be related to the 5vdc Auxilary Control power voltage.If it is not a precise 5.1vdc and free from noise, it may generate E55, User Parameter Checksum. You may try (for testing purpose) to remove the external 5vdc supply voltage from pins 2 and 3 of CN-1, power the unit and see if E55 occurs again. If not, the 5 Vdc external power could be the problem. Using a CN-1 BreakOut Board 2090-U3CBB-DM44 that has a filter inside could solve the problem. If you have a sercos drive, use a 2090-U3CBB-DM12 instead. Hope that helps... - fuzzy logic \\n </s>