Johannes Stezenbach wrote: > 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 > If manufacturers would shift to (the more expensive) tantulum capacitors, then that would be of no problem i believe.. But the problem was seen on new cards as well. Electrolytic capacitors < than a year old, rarely dry up, but no one can say for sure how old the capacitor has been there with the manufacturer. :-( Manu
