I just put the wraps on my last clock, the IN-14 Nixie Clock, and I already can't wait to start another one! I found some really huge ILC1-1/8L 7-segment VFDs on eBay. They're almost 4" tall. The digits themselves are 2.25" tall. Massive!

I also picked up a bunch of IV-25s to use as a PM indicator and colon separators. To my surprise, the eBay seller threw in two ILT1-5 L tubes! They are really cool. They almost look like they were made to match the ILC1-1/8Ls.



I looked online for a datasheet for the ILC1-1/8Ls. I managed to find this:



I took that and made my own pinout image. As it turns out, there's 3 pins connected to the grid, but you only need to power one of them. Same with the filaments; there's two pins for each, but you only need to use one on each end.



I applied 3 volts across the filament and 25 volts to the grid and segment G. Voilà! It works.



Moving on to the IV-25s…

After seeing the ILT1-5 L tubes, I'm not sure if I'm even going to use one for the PM indicator any more. It seems so small by comparison. I just might have to order another one.

Again, I found the pinouts online. This one is a little easier to figure out. There doesn't seem to be a dedicated pin for the grid; unless it's internally connected to each anode.



Pins 1 and 6 are the filaments. I applied 2 volts across the filament and 20 volts to the other leads. Pretty cool. Maybe I'll put one in the clock for a day of the week indicator. We'll see.



Lastly, the ILT1-5 L. I didn't find much information online for this tube at all. I did manage to find the eBay seller's page for it. He offered a few technical tidbits, but no mention of the pinouts.



For a tube that only has five indicators, there sure is an overabundance of pins.



I managed to figure them out and make my own pinout image. I applied 4 volts to the filament. As it turns out, theres multiple pins for the grid. You only need to apply ~25 volts to one of them. I then applied 25 volts to the other anodes connected to the indicators. It works!



Pretty cool tubes. I can't wait to get started on a new clock. It's going to be massive!

See this project from start to finish:
More VFDs!!!
VFD Breakouts
Large VFD Clock - Part I
VFD AC Filament Driver
Large VFD Clock - Part II
VFD AC Filament Driver V1.1
Large VFD Clock - Part III
Large VFD Clock - Part IV
Large VFD Clock - Part V