Author Topic: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work  (Read 9926 times)

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Offline EEVblogTopic starter

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EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« on: February 27, 2024, 03:39:30 am »
How VFD (Vacuum Fluorescent) Displays Work.



Extracted from a hacking video #717:
 
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Offline floobydust

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #1 on: February 27, 2024, 04:23:02 am »
I had a moment rejuvenating a 34401a VFD, connected power to it and it didn't light up. Applied filament power and +30V on the segments, grid floating.
I expected segments to light (normally on unless the grid biased negative) but it stayed dark.
Turns out the "grid" works like a screen grid, not a control grid.

I do the usual filament bake off up to 2x Vfil absolute max, and then also a grid bake off was needed. There is some buildup on it as well.
 

Online Ian.M

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #2 on: February 27, 2024, 06:33:02 am »
Useful VFD links:
Futaba's VFD Characteristics & Operation guide AN-E-1103A http://www.vwlowen.co.uk/arduino/vfd/VFD-Application-Note.pdf
Noritake's A Guide to Fundamental VFD Operation
https://www.noritake-elec.com/technology/general-technical-information/vfd-operation
 

Offline ksio89

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #3 on: February 28, 2024, 04:45:23 pm »
I had a Sony MHC-DX7 shelf stereo/mini system that bought in 2000 or 2001, was the display a VFD or just an LCD one?




 

Offline floobydust

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #4 on: February 29, 2024, 07:17:21 pm »
VFD's are superiour for readability in sunlight and low temp (below -30°C) I used them a lot in industrial panels that are located outdoors. Instead of low temp fluid and heaters in LCD's.
Noritake iTron/Futaba were kings making the best VFD's but LCD's took over and had the lower power consumption, you don't need a few watts for the filaments.

Interesting the Korg Nutube 6P1 (by Noritake) is just a VFD as a low voltage twin triode. They're just exploiting the non-linearities I think THD 1-20% very fuzzy and perhaps corny.

Sony MHC-DX7 uses a VFD https://elektrotanya.com/sony_mhc-dx7.pdf/download.html#dl
 
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Offline thm_w

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #5 on: February 29, 2024, 10:31:13 pm »
I had a Sony MHC-DX7 shelf stereo/mini system that bought in 2000 or 2001, was the display a VFD or just an LCD one?



The manual calls it "fluorescent indicator tube" so its some form of VFD.
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Offline Ranayna

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Re: EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work
« Reply #6 on: March 01, 2024, 01:47:28 pm »
May i ask what led you to extracting this part from an old video?
Not that i mind really, it was a bit of a "blast from the past" :D And i remembered many points from the original video.

Is it just to make this aspect easier to search for and find this video?
 


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