VF Display

[loopyloo]

I've got a STB recorder with a dim Vacuum-fluorescent display.
Is there a way to get the brightness back into it ?

[gordon_s1942]

Brand, model and age ?

[mtv]

Possibly display power supply has gone low in voltage.

I've seen this on a couple of FD's.... Involves tracking down the faulty component/s.

[TVguy]

VFDs will dim with age in the same way that any vacuum tube will suffer from "low emission".
The heater / cathode wire will degrade and gradually dim the display. The modern design philosophy of using DC as the filament voltage does not assist in their longevity.
Typically an approximately 3 volts DC should be present across the extreme ends of the VFD pins. This will also be biased at approximately -20 V to -30 V when referenced to ground return.
The odd thing with VFDs is that the segments that are mostly unlit seem to dim first. PSU capacitors may be the cause; however, once the cathode is poisoned, there is no return to full brightness.

[loopyloo]

There's around 5v on the end pins and -25 when checked to ground.
When the unit is off, I notice some of the segments are white and others are light grey in colour.

[bazzle01]

If remember quite a few years ago I just increased the supply voltage by reducing a power supply series resistor.

[loopyloo]

Thanks all. I ended up scrapping the unit when I found out it had a really crappy user interface.
Just too clunky to use so the hard drive will get another use now.