28 Jan
2002
28 Jan
'02
7:46 a.m.
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%2Fprodseā¦
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