| VLT 131B0052 turns on for split second and turns off repair | |
|---|---|
| Device | VLT 131B0052 |
| Affects part(s) | Main power board (CPU) |
| Needs equipment | Screwdriver set, soldering iron, soldering station, multimeter |
| Difficulty | ◉◉◌◌ Medium |
| Type | Part replacement |
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Problem description
Repairing a danfoss VLT 131B0052 VFD "inverter" that when supplied with 3 phase AC, turns on for a split second (led/operator panel) and turns off immediately after.
Symptoms
- Turns on then off immediately.
- No communication.
- DC link is at full voltage (550v)
Solution
After verifying that all the power rails are at proper voltage and no shorts on the board, it's safe to assume the microcontroller itself is damaged. The board must be replaced or the microcontroller if you have a donor. You can't buy the MC and replace it directly, they have custom firmware on them. Unless it's a donor working one, you must replace the entire board. The IO board and the operator panel are both working fine! No need to replace those.