PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, tony duell wrote:
> On Wed, 22 Jul 2015, ANDY HOLT wrote:
>
>>> Do you seriously replace both headlight bulbs when one fails? I know of
>>> nobody who does that. Generally you carry a spare bulb kit and a screwdriver
>>> and if a bulb fails, pull over and change it.
>
>> and - like the capacitor replacement question this is an "it depends". 
>> For some cars - including the Mercedes A-class (at least earlier 
>> models) - it is almost impossible to change the headlight bulb when the 
>> car is at ground level because it is accessed through a hatch in the 
>> wheel arch, whereas if the car
>
> ARGH!!!
>
> But presumably you carry a jack and tools to change a wheel. Can you not 
> just remove the wheel on the correct side to reach the hatch (not that I 
> want to work on a car not supported on proper axle stands...)
>
> Having had a number of bulbs that failed shortly (but not very shortly) 
> after installation (nothing to do with headlamps, and not quartz-halogen 
> bulbs so it was not contamination of the envelope that was the problem) 
> I wonder if necessarily changing a good bulb is a good idea...

I can't say I've previously heard of that being done with automotive 
bulbs, but I do know that some pinball guys who do this. After a couple of 
lamps go out, they will replace them all at the same time because it 
usually isn't easy to change them, and once the lamps reach a certain 
number of power on hours, they start failing more and more frequently.