VSD display blank / drive appears dead
The drive's display is blank and it shows no signs of life — no keypad, no LEDs — so nothing can be operated or diagnosed from the panel.
Safety first
A 'dead' display does not mean the drive is safe. The DC bus can still hold a dangerous charge. Prove dead and wait the discharge time before touching internal parts.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
No incoming supply to the drive
Most likelyAn open isolator, tripped breaker, or blown supply fuses means the drive gets no power.
- 2
Detached / faulty keypad
#2A removable keypad that's unplugged or faulty looks like a dead drive though the drive may be powered.
- 3
Blown internal supply / control fuse
#3An internal control-supply fuse or component has failed.
- 4
Drive internal power-supply fault
Least likelyThe drive's internal power supply has failed.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Confirm incoming supply at the drive's input terminals (and that upstream protection is on).
Rated input supply present at the drive.
Drive is powered — check the keypad/connection and internal supply.
No incoming supply — restore it upstream (isolator/breaker/fuses).
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
VSD display blank
→ step 2 - 2decision
Is incoming supply present at the drive?
Yes→ step 3No→ step 4 - 3decision
Does a properly connected/known-good keypad come alive?
Yes→ step 5No→ step 6 - 4result
Restore supply upstream (isolator/breaker/fuses).
- 5result
Keypad/connection issue — reseat or replace.
- 6decision
Is the accessible internal control fuse intact?
Yes→ step 7No→ step 8 - 7result
Internal power-supply fault — refer to support.
- 8result
Blown internal fuse — find why before replacing.
Common mistakes apprentices make
- Assuming the drive is dead/safe when the bus is still charged.
- Not checking a detachable keypad is plugged in.
- Overlooking upstream supply (isolator/breaker/fuses).
- Replacing internal fuses without finding why they blew.
When to stop & escalate
Internal power-supply faults typically go to the manufacturer's support/repair. Never open a drive without proving dead and observing discharge times.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
No control voltage in the panel
Nothing in the control circuit will operate — contactors won't pull in, indicators are dead, the PLC may be off. The control voltage that should be there simply isn't.
VSD trips on undervoltage / loses supply
The drive trips on undervoltage — the DC bus drops too low, often on start, under load, or with supply dips, and the drive shuts down to protect itself.
VSD powered up but won't start the motor
The drive is energised and the display is alive, but it won't run the motor. No fault may be shown — it just sits in 'ready' or 'stopped' and ignores the start command.