Panaplex display history

Jon Elson jonathanelson at
Mon Jun 1 10:31:18 CDT 2015

On 06/01/2015 04:03 AM, Christian Corti wrote:
> On Sat, 30 May 2015, Jon Elson wrote:
>>> Is there a good reason why filament lamps were used on minicomputer
>>> front panels until the mid 1970s? Things like the PDP11/45, Philips 
>>> P850, etc
>>> all used filament bulbs, not LEDs.
>> Inertia!  The 11/45 was designed before LEDs were available, and so 
>> they never changed.  To do it right, the PC board would have to be 
>> re-designed to
> Hold on! Most 11/45 have LED frontpanels (such as mine from 1974). The 
> earlierst ones might have bulbs, but they switched to LEDs during 
> production.
OK, I know 11/70's had LEDs, but all the /45's I worked with had bulbs.  
Ours was SN 343, which I guess must have been an early unit.  We got it 
used in 1976 or possibly 1977, and it looked pretty "well used" when we 
got it.


More information about the cctalk mailing list