[linux-dvb] Re: DVB corruption after a month or so.

[Andrew de Quincey <adq_dvb@lidskialf.net>]

Apologies if this is sent twice - I just upgraded my mail system and it 
decided to discard messages at random for a bit.

> Hew... :)
>
> Andrew, I though I was the only one having this problem :)
>
> I experienced this problem a long long time ago (almost 2 years ago). I
> manage a cluster of servers (S and T) and suddenly, they all had the
> problem you described.
>
> I was also thinking of heating problems, and I left the machines powered
> off for a night. However, it seemed strange to me from the beginning that
> there was a heating problem because those machines were situated in a
> server room (from Tampere Univ. of Tech) having a huge and noisy cooling
> system.
>
> I tried everything, reinstalling drivers, my application (they are running
> with my server-application), everything possible and still the same.
> Corrupted streams at the output. I started thinking of network problems,
> hardware failures, etc.
>
> In the end I had to reinstall the machines (completely, including Linux),
> and only then it worked again. No need to tell you how confused I was after
> this experience...
>
> So, if you find out what is the problem please share it, I am curious to
> see what gave me a week of headache. :)

Yeah, that definitely sounds like it... glad to hear someone else has had it 
(well not glad you had problems - you know what I mean :) 

More interesting stuff from me though: although powering down fixed the DVB-T 
machines, it didn't help the machine where the DVB-S card had the problem 
(tuned to RAI1/2/3 on hotbird)

We tried some tests. We replaced the DVB-S card in that machine, but the new 
card had the same problem as well.

We tried tuning to RAI1/2/3 on a different machine. That one got perfect 
reception (note this machine's signal is coming off the same 
multiswitch/dish).

We tried tuning a different channel ("Fashion TV") on the problem machine.. 
and it was perfect!!!

We tried tuning back to RAI1/2/3 on the problem machine. It still had errors.

At this point the clients were breathing down our necks, so we swapped the 
channels round to keep them happy as that gave them their TV back.

However, its obviously not the cards at fault, as a new one had the same issue 
in the problem machine. It has to be the machine itself. 

Seeing the recent posts about sensitivity to the power supplies, I'm beginning 
to wonder if the PSU is somehow causing this. Maybe the problem machine had a 
power supply "on the edge", and its just degraded a bit over the months its 
been on (capacitors drying out slightly maybe) so that its now starting to 
give interference on certain frequencies. Does this sound feasible to anyone?