- Error code
- 77
- Category
- Self-diagnosis
- Manufacturer
- SMA
- Models
- Sunny Boy (SB)
1What the error means
77 is a self-diagnosis code of the older Sunny Boy models. The inverter detected an internal disturbance in its power electronics or control circuits and stopped feeding the grid for safety reasons.
2Possible causes
- Fault on the power or control board
- Faulty grid relay or measuring circuit
- Thermal stress after years of operation
3What to do
- Switch off the AC switch and the DC switch, wait 2–3 minutes and restart.
- If the code returns, it is an internal fault — the inverter needs to be checked in our lab.
4Repair by Aineas
You send the inverter to our lab in Thessaloniki. We diagnose it, inform you of the fault and the cost, and the repair starts only after you approve it. Every inverter is tested under simulated operating conditions before delivery.