Searching for old DEC 12V frontpanel bulbs - test-drb@ccmp.vtda.org

28 Jan 2002

At 05:53 AM 1/28/02 -0800, Ethan wrote:

...
  I'm restoring some pre-TTL DEC stuff (R and W
series logic) and I need
 a handful of front panel bulbs.  Unlike the later bulbs with a plastic
 base and strong wires to solder to the PCB or to plug into socket pins,
 these are like a kernel of corn, with two fine wires coming out of the
 glass envelope at a slight angle with no supports of any kind. 
Sounds like a standard T1_1/2 (about 3/16" diameter) or T1_3/4 (about 1/4"
diameter) wire-ended bulb.  There are still a few companies that make them.

...
  If DEC was underfeeding these bulbs to extend their
life, I would expect
 that the bulb should be rated at 14V-16V.  I measured slightly over 12VDC
 in circuit, but well within a 5% tolerance. 
The Farnell catalogue lists a few that are 14V.  The correct bulbs for my
RL02 drives are 14V, fed from a 12V supply, as you say.

...
  I have checked the online manuals I could find, but no
mention is made
 of the nature of the bulbs for 1966/1967-era DEC equipment.  Any ideas? 
Take a look at Farnell's online catalogue, at
http://uk1.farnell.com/Search/search4-frame.jhtml?_DARGS=%2Fcommon%2Fprodse…
and search for part number 328900.  That should get a page with a small
picture; click on the image to get a table showing the charcteristics of
that family and a bigger picture
(http://uk1.farnell.com/Search/level_5.jhtml?PRODID=37469&SKUID=35454)454).
 Part number 3159346 will show you a different make (but only 12V).  At
least you'll be able to see if that's the right shape/size and perhaps help
find a US manufacturer or supplier if you don't want to order from the UK.

BTW, if you try part number 316216 you'll find something like the bi-pin
ones for your PDP-8 panel.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York