19 Aug
2008
19 Aug
'08
5:28 a.m.
The thing that is fishy
about it is that it seems to be a 12V bulb. The drawings clearly show
the bulb being driven from +5V, so it seems that a 12V bulb would have
been serious overkill for that application.
From my reccolection they were seriousley under run and
very rarely
replaced, they were not "bright" as you would expect a lamp
to be.
Mike
Web - www.soemtron.org
Email - mike at soemtron.org
Looking for a PDP-7 (some hope!)
----- Original Message -----
From: "Vincent Slyngstad" <vrs at msn.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Tuesday, August 19, 2008 12:45 AM
Subject: [personal] **JUNK** Re: WTB: DEC PC04 Paper Tape Reader/Punch
From: "Ethan Dicks" <ethan.dicks at
usap.gov>
On Mon, Aug 18, 2008 at 10:55:14AM -0700, Vincent
Slyngstad wrote:
I did check that it's being run from +5V through a 2 ohm 10W
potentiometer.
So I thought a 6V automotive dome light would be about right.
Isn't it basically exactly an old-school 6V
automotive dome light?
It was a dome light, but I'm not certain about the voltage right now.
It's entirely possible it's a 6V bulb derated to 5V, but I'm not sure.
The best I recall is finding an Osram part number
_somewhere_, but
not being able to find that bulb in their modern catalog and no
crossreference.
> If it's DEC part number 12-04903, then that's available here:
> http://www.atlantalightbulbs.com/ecart/nw012104/PHILIPS6411LAMP10W12V.htm
If you have the Osram part number, we can check that it is or is not the
12-04903, which is Osram #6411. That's the lowest voltage Osram bulb I
found referenced in the 9/1/70 version of the DEC Spare Parts Reference,
Volume II, section 12 (purchased vendor items). The thing that is fishy
about it is that it seems to be a 12V bulb. The drawings clearly show
the bulb being driven from +5V, so it seems that a 12V bulb would have
been serious overkill for that application. Maybe that's why they
thought they'd never need replacement :-).
Vince