LED displays (TIL305, TIL308, etc.)

Roy J. Tellason rtellason at verizon.net
Mon Sep 29 19:42:38 CDT 2008

On Monday 29 September 2008 18:44, Ethan Dicks wrote:
> Hi, All,
> Since one of the first computers I ever got my hands on as a kid (Quest
> Elf) happened to have TIL311 HEX displays, I've long been fascinated with
> display technology of that vintage.  I was poking around for images of
> some of the related displays to the TIL311 and ran across a couple of
> links with pictures and some history...
> http://www.decodesystems.com/old-displays.html
> http://www.decadecounter.com/vta/tubepage.php?item=33
> In particular, I notice that one of the displays I have one of is a
> TIL305 or MAN2 (no logo on mine).  I was also looking at the TIL306
> or TIL308, but don't happen to have any of those.
> I do have a reasonable quantity of TIL311s for my various Elf and Elf2000
> machines and even a set that came with an INS8073 SBC.  I would love to
> find a couple more TIL305s so I can round out an old project, plus I had
> an idea for a project that would be interesting to use TIL306s or TIL308s
> (don't care about where the decimal point is, so either is acceptable),
> but ISTR some discussion on the list a while back about those in
> particular, possibly as replacements to some HP counter, and how difficult
> and expensive they are to obtain.
> TIL311s are frequently found on eBay for various prices; I've gotten
> them myself for as little as $2.50 each in small quantities.  I doubt
> that TIL306s and TIL308s are anywhere near that inexpensive, no matter
> what the quantity, but I thought I'd ask if anyone has recently found
> any place selling them.  I'm not trying to repair a bit of vintage kit,
> so I'm not willing to pay "any" price for them - if they are too expensive
> (as I suspect they are), then I will find some other display.
> Yes, non-driven LEDs are inexpensive to free and modern microcontrollers
> can drive wads of LEDs easily and cheaply, but what I'm going for is a
> 1970s look with 1970s components (i.e., popcorn-logic driven, not micro-
> processor-driven).  The advantage of the TIL306s and TIL308s is now what
> it was then - a high level of integration reducing the overall wiring
> complexity and parts count.  The disadvantage now as then is that the
> displays are more expensive than the entire rest of the device.
> They still look cool, though, and that's the real point.


This is neat stuff...

I built a digital counter for a guy back in 1975,  using TTL and displays that 
I bought on Canal St. in NYC.  I still have some number of that sort of 
display around,  and haven't figured on any particular use for them yet,  
plus some that I've salvaged a bit here and there,  some two-digit parts,  

No 7446/7 chips on hand to drive them with,  though.  Or any of the 
4000-series CMOS either.  :-(

I was always wanting to get my hands on some of those hex or better yet 5x7 
displays back in those days to play with.  Oh well.

Definitely nifty stuff,  for sure.

Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

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