• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Inverter for vacuum fluorescent display

Status
Not open for further replies.

2PAC Mafia

Member
Hi guys,

I have repaired equipment with inverter TDK PCU-685, it´s 24Vdc input with two transformator outputs, each one with 3Vac + 3Vac output with a common point. Total 10Vpp senoidal 67KHz signal each transformator. Some of these transformators are burnt so I need to replace these inverters but it seems there is nothing at Internet to buy them originally.
Any inverter with those data is probably good to replace original one, or even four inverters with 3Vac 67KHz output, I can adapt them in the circuit.
 

dr pepper

Well-Known Member
Most Helpful Member
Yes sounds like a bespoke item, I was thinking electronic lighting transformer but they are mains input.
 

2PAC Mafia

Member
Thanks, I´ve been thinking about DC-DC small open frame to take the AC output before rectification to get the high frequency signal, but I guess it wouldn´t be senoidal.

It seems all these VFD are working with 3Vac signal for filaments so there should be inverters for this, I couldn´t find them.
 

dr pepper

Well-Known Member
Most Helpful Member
The filament really should be Ac, but will work from Dc on some displays, just the brightness might not be even, I dont know your particular display however it might work off a square wave too.
You might be able to get a standard module for driving the filament, could be tricky to find though.
 

throbscottle

Well-Known Member
The usual thing is to have a filament driver chip, but you can roll your own using an audio amplifier IC, such as shown here: http://magictale.com/2603/revisiting-vfd-psu-part-ii/
Your post really caught my eye because I have been working out how to drive my own vfd recently! It's normal to drive the filament from a square wave in modern equipment.
 

gary350

Well-Known Member
When I was in high school 1968 we use to turn on fluorescent light bulbs with 2 D flashlight batteries. Been a long time we had 2 D batteries on 1 end of the fluorescent tube and a wire running the length of the tube to the 2 pins on the other end of the tube. I can't remember the exact circuit but the 2 D batteries heated up 1 filament then the light bulb came on when we pushed the other button. It was very simple. Do some experiments with batteries see if you can learn how to turn on the fluorescent light then you know how it works then you can buy what you need to make it work with a transformer. We use to take fluorescent light bulbs camping and run them on flash light batteries it will light up the whole inside of the tent. D alkaline battery puts out 8 amps. Enough power to have light several times for a few minutes each time for a 2 day camping trip. We thought we were real smart, we had to show off our smarts. LOL 2 ft long fluorescent tubes were easier to light up than 4 ft. 4 ft bulbs & 8 ft bulbs are not very handy for a flashlight. LOL.
 
Last edited:

throbscottle

Well-Known Member
I don't think it's a fluorescent lighting tube he's dealing with, I thinks its a vacuum fluorescent display. Unless in this case vfd actually means variable frequency drive. I don't think those have a filament though ;)
Interesting all the same. I didn't imagine you could light one of those tubes with just a couple of batteries.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top