In message 
          Big Bad Bob  wrote:

>On 01/20/19 01:33, Chris Green wrote:
>> My RaspberryPi has rebooted itself a couple of times recently and
>> ended up in a non-working state.  In particular it has no ethernet
>> connection which is rather unfortunate as it's headless.
>
> > Power down/power up fixes it but having run for months without
> > problems previously it would seem there is something wrong.
>
>overheating?  have you tried a CPU heat sink?
>
>might also be something simple, like power spikes.  a Big Fat Capacitor
>across the 5V input (with a 0.47uF ceramic in parallel with it) might
>help.  Rapid power sags, caused by lots of possible things, is a likely
>cause for unplanned reboots.

And make sure the cable between the PSU and the Pi has a low enough
resistance - short and fat is good, in this instance :-)

Dave

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