# Scrambled VFD display at idle

**URL:** https://forum.avidcnc.com/t/scrambled-vfd-display-at-idle/4618
**Category:** General Chat
**Created:** [April 21, 2025, 12:54pm UTC](https://forum.avidcnc.com/t/scrambled-vfd-display-at-idle/4618 "2025-04-21T12:54:17Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![JtheB](https://avatars.discourse-cdn.com/v4/letter/j/b77776/32.png) [@JtheB](https://forum.avidcnc.com/u/JtheB)
#### Post date: [April 21, 2025, 12:54pm UTC](https://forum.avidcnc.com/t/scrambled-vfd-display-at-idle/4618/1 "2025-04-21T12:54:17Z")

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I’ve got two unusual symptoms occurring with my CNCDepot VFD case.

1. The case fan sometimes hums loudly which gets amplified by the case itself - sometimes resolving itself within minutes and other times not. It’s as if it’s over-revving or out of balance somehow.  

2. The Delta VFD displays a scrambled set of numbers ranging from about 3.0 to 6.0 - again, at idle and not connected to software.

Their relation to one another is tbd.  
They don’t _seem_ to effect machine performance but neither seems normal and I’d like to resolve them.

One suggestion was checking for power surges but I don’t own an oscilloscope.  
Another was a grounding issue but I’m currently in the dark on how to check for that.

Anyone experience either of these things before?  
Much appreciate.