On Thu, Jun 09, 2005 at 12:21:16AM +0100, Andrew de Quincey wrote: > > So to summarise my current findings: > > *) Setting the tone every 60 seconds does not help. > > *) Setting the tone when the lock is lost causes it to be regained in under > > 100ms. > > *) If you don't set the tone/reg0x08 on lock loss, you will never regain > > the lock. > > *) The contents of register 0x08 of the stv0299 stay constant. > > *) It cannot be noise/traffic on the i2c bus changing other registers since > > the only thing needed to fix the issue is to set register 0x08 again. > > *) No i2c traffic to the stv0299 besides reading the lock status occurs > > after the initial tuning attempt. > > *) Only a few cards are affected. Cards tuned to the same channels on other > > sites are fine. Cards using the same multiswitch at the same site are fine. > > *) At a site with the issue, channels can be manually reassigned between > > cards/machines until a stable situation is found. This is very time > > consuming though. > > *) Temperature is unlikely to be a cause. > > *) This problem occurs across a whole range of stv0299 based cards (we have > > several vintages of them from the last few years). > > *) There is no pattern temporally to the lock loss. > > *) The problem occurs across different multiswitches by different > > manufacturers. > > *) The signal is perfect (BER==0) up until the time the lock is lost. > > *) The problem _may_ affect stv0299 based Twinhan cards as well, but this > > needs verified. > > Another one: > > *) It is not interference from other DVB cards in the same machine - the > machine I am testing stuff on only has one DVB-S card in it (and it doesn't > have any DVB-T cards in it either). Maybe some dried up electrolytic capacitor making it senstive to small power drop outs, like in: http://defiant.wavecon.de/~alex/dvbbug/dvbbug.html Johannes
