[mythtv-users] HDHR - occasional "Added 0 devices" / "Unable to find a free device" when attempting to record a show

[Hika van den Hoven]

Hoi Will,

Wednesday, November 29, 2023, 8:40:30 PM, you wrote:

> On 11/25/23 6:46 PM, Will Dormann wrote:
>> The HDHR device is never terribly busy, but I see in the above:
>>   Added 0 devices from 131F1E8E
>>   Unable to find a free device


> So just to follow up for the benefit of anybody who may be playing along:

> I recently attempted to ping my HDHR device from my MythTV box, and sure
> enough I was (un)lucky enough to catch it at a point where the device 
> was not answering ping responses!  At which point, this is clearly 
> beyond the scope of being a problem in anything MythTV related.

> To eliminate variables, I tried swapping out the Ethernet cable and also
> the power supply to my HDHR box.  In a 90-minute ping session to the 
> device, over 12% of packets are lost.  Similarly a 90-minute ping 
> session to another device (a NAS) connected to the same network device
> (the Verizon Wifi box, which has a few Ethernet ports) resulted in 0 
> packet loss.

> The HDHR device was connected to a port on the Verizon AP that is 
> labeled as 10GbE LAN.  Just on a whim, I switched the NAS and the HDHR
> so that the HDHR is on a regular (non-10GbE port) and the NAS device now
> occupied the 10GbE port.  I also switched back to my original ethernet
> cable and PSU for the HDHR.  The result?  Both the NAS and the HDHR have
> gone through a 90-minute ping session with zero dropped packets each.

> I probably won't know for close to a week, but I'll predict that my 
> "randomly" missing HDHR recordings problem might be gone with this change.


> The lessons here are:
> - Any system with more than one variable will get increasingly more 
> complicated to troubleshoot with the addition of any new variables.
> - Don't kid yourself by thinking you have any idea of how computers 
> work.  :)



> -WD

I have noticed before that ethernet (and other) cables that do
properly connect to one connector do not automatically do so to
another, especially if the cable is self made. Also here there are
multiple variables. 
- how deep are the connector plates in the male connector pushed in.
- how springy are the connector wires in the female connector.
- form variation in both male and female connector.
- random dust.
- small unnoticeable damage (wear and tear).
- starting corrosion.

And probably more.

In my experience disconnecting and reconnecting and/or swapping around
9 out of 10 times solves connection problems. Even problematic memory
modules and pci(e) cards often work again for years after
disconnecting, cleaning and reconnecting.

With digital connections even slightly raised electrical resistance
can mean some 1 states are missed. Like the noise you hear with older
analog audio cables and connectors, where turning around the plug in
the jack can reduce or increase that noise.


Tot mails,
  Hika                            mailto:hikavdh at gmail.com

"Zonder hoop kun je niet leven
Zonder leven is er geen hoop
Het eeuwige dilemma
Zeker als je hoop moet vernietigen om te kunnen overleven!"

De lerende Mens