From visual inspection, the filaments in these vacuu-fluroescent displays look like bare wire, which would make them some sort of doped tungsten alloy.. which doesn't really ever wear out.
The only problems I have ever seen is due to phosphor fatigue. The display stops glowing on whichever digit is on all the time... and you see this as unequal brightness between the digits. I have never seen a vacuum fluorescent display just fade away in any reasonable time. They seem to go for years and years. I have alarm clocks and ovens, and microwaves with these displays some of which have been glowing for around 40 years now, and still going strong. I have seen vacuu-fluorescent displays that have gone dark, and found that the reason is the filament supply has quit...usually due to a bad electrolytic capacitor. -Chuck Harris Don@True-Cal wrote:
The 3458A DISP? command, rather entered from the front panel or via a GPIB Command is not adequately discussed in the User's Manual IMO. There are four numeric values 0,1,2 & 3 plus the ability to enter a string value as mentioned below. All four values are supported via the GPIB, but only 0,1 &2 are valid modes for the front panel DISP? command - the front panel DISP? 3 seems to be accepted and interpreted the same as DISP? 1 (On). The value 0 (Off) seems somewhat pointless and simply places dashes across the display. The value 1 (On) is the default and normal mode. The value 2 (Msg) displays control messages only. These three modes would obviously offer no help to prolonging display life since the display filament would need to remain on. The interesting DISP? 3 (Clr) is the one in question rather is removes power to the display filament providing some help for display life. I'm not sure without actually getting inside and testing if filament voltage is present or not. Checking t
h e
schematics for a display filament voltage interrupter might also be a clue, but would still be firmware dependent. I use Agilent VEE for 3458A control and plotting and have provided a dynamic display control using DISP? 0-3 modes and I often leave the display in mode 3 (Clr) for long plot cycles (sometimes weeks). In this mode, the display is completely blank, including no enunciator (sampling) indicators at all. My hope is that the display filaments are off. Anyone know for sure? Don -----Original Message----- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of new Sent: Saturday, April 11, 2015 12:09 AM To: volt-nuts@febo.com Subject: [volt-nuts] dark display for 3458 Hi, again... Now that I have the keysight connection expert running my two sick 3458s, I don't need to look at data on the displays. To keep them from burning out, I wanted to turn them off. I found a workaround of: DISP 0,' (16 spaces) .' This put a period on the bottom of the blank screen and moves it 16 spaces to the right..... right off the screen! So now the display is dark and only shows things like the 'err' message. QUESTION - will this kill the 3458 or its display somehow? Willy _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
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