Is this a VFD or LED display? - Page 1
Forum section: electronics / beginners

author: cdev
author_rank: Super Contributor
timestamp: December 23, 2018, 02:50:36 pm
content: I recently picked up this piece of e-waste very cheap which was originally a piece of rackmountable broadcasting equipment that now is apparently obsolete. It is meant to display a bunch of different data relating to time code.On its front it has a matrix of switches and this VERY nice looking, bright alphanumeric display, which I suspect may be a VFD behind a sheet of green plastic. It looks to me like a VFD.Its either that or an LED.Anyway, I would love to be able to remove the main circuit board completely and re-purpose the case and its display and low profile encapsulated toroid 12+5v power supply (and 9 BNCs and two DB9s on its rear panel) to use with my GPSDO.Its not so visible in any of the pictures but the individual portions of the display alternate up and down in a particular way. Which suggests VFD tubes to me. I'll have to get some better pictures.Does this suggest any particular display manufacturer?I have to clean my desk and put down my ESD mat, before I go taking this apart further. The entire front panel looks as if it might be useful with fairly minor modification IF I can figure out how to talk to it.Its probably a standard protocol, accessible via the IDC header which can be seen. I suppose I could insert my own pair of IDC connectors leading to a breakout board in between it and the PCB and sniff it with my logic analyzer, if I cant figure it out any other way.

author: helius
author_rank: Super Contributor
timestamp: December 23, 2018, 03:13:15 pm
content: My vote is LED. No VFD I have seen consists of separate "tubes": they are constructed in a single glass envelope with a vacuum stem on the bottom center or on the side. VFD also do not show the grid of inactive segments like that, they are higher in contrast and more bluish in color (although color filters are sometimes used).

author: ledtester
author_rank: Super Contributor
timestamp: December 23, 2018, 03:39:14 pm
content: I also vote for LED display... something like this:https://uk.rs-online.com/web/p/led-displays/4965361/Pic attached below. Search for (HDSP | HCMS | osram opto) alphanumeric displayto find similar items.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 23, 2018, 03:45:54 pm
content: I'll say LED.The VFDs I've seen were all in one tube of mostly transparent glass, where one could see the segments and the very thin longitudinal filament wire(s).

author: cvanc
author_rank: Frequent Contributor
timestamp: December 23, 2018, 04:26:12 pm
content: Looks like an Evertz box? Send a photo of the entire front, I might have a manual.

author: cdev
author_rank: Super Contributor
timestamp: December 23, 2018, 04:30:07 pm
content: It is, it's a 5300.

author: cvanc
author_rank: Frequent Contributor
timestamp: December 23, 2018, 05:12:28 pm
content: Sorry I don't have a manual for the 5300 but I bet it's a LED display.

author: cdev
author_rank: Super Contributor
timestamp: December 23, 2018, 05:29:18 pm
content: I'm now pretty sure this is a HDSP 211x based display. Thank you everyone!

author: Canis Dirus Leidy
author_rank: Regular Contributor
timestamp: December 25, 2018, 04:08:58 pm
content: Quote from: helius on December 23, 2018, 03:13:15 pm(out of sense of pedantry) Not always.™ Some VFDs (like IV-26) give the same effect as if it were a matrix of individual tubes:

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: December 26, 2018, 12:22:17 am
content: Quote from: cdev on December 23, 2018, 05:29:18 pmYeah I work on systems using 5x5 matrix just like this (for low pwr). Definitely these are very similar but 7x5 dot displays.They overflow char’s from one display to the other for longer words ...neat displays and long lasting.Sent from my iPhone using Tapatalk