Tivo losing sound - comes back after reboot

[chrishowell]

In the last week or so, I've found that the Tivo is losing sound for TV programmes.

This includes live TV and recordings. The Tivo sound effects are still present and there is sound from the STB that is connected to the Tivo.

A reboot will restore sound but this seems to be happening every couple of days.

I'm running an S1 SA Philips Tivo with release 1.4. The machine has been running pretty well since it was imaged and the only thing I've been doing different lately is using vserver to extract files via Tivotool.

Anyone got any advice?

[Darren King]

Losing sound can be hardware related and in the symptom you describe IF it is hardware related then it will be the Micronas sound chip which can be repaired. However firstly my advice is to grab a small hard disk (2GB and up is fine) and run it as a test hard disk with nothing more than the standard oztivo image and see if you can replicate the problem. If you can then it is 99.9% hardware.

[zollymonsta]

I would be interested to see if your problem is the same as mine.

Next time you lose sound on live tv, can you change channel and see if the sound comes back? THis is the problem I occasionally get (changing the channel brings the sound back). It's also recorded like that. Darren may remember me trying to find where this fault was too (a few months back). Couldn't pin it down at all. And it also hadn't done it for a while (I did a re-image with the latest image when it was released).

The tests I did were with a small hard drive, Could not replicate the problem.
Also the output from the power supply was checked with a multimeter and all was ok.

No biggie really, doesn't bother me too much. But always good to find out why it's doing it.

[chrishowell]

Thanks for the responses.

I'll keep an eye on the issue and will try and give the new image on a spare HDD a try but may not be able to do this for a week or two.

If it does need a repair Darren, would you also be able to fix the LED on the front? Doesn't show when the unit it recording.

zollymonsta, the sound doesn't come back after changing channels. I have to reboot my Tivo to get sound back.

Thanks,

Chris

[Cods]

G'day, I have exactly the same problem as zollymonsta, been happening pretty much ever since I plugged the TiVo in after getting it, details as follows:
- only occurs on the ABC, never on any other channels
- intermittent fault, have not noticed any patterns
- I have observed it occur only when TiVo records, and seems equally likely to occur both
a. when TiVo has to change channels from another channel (sound always fine on other channels) to record on ABC, and/or
b. when TiVo already on ABC and not recording (and sound already OK) and then starts a recording
- can't remember it ever occurring when I change channel to ABC manually
- when the problem occurs and I happen to be watching, a manual change of channel away from ABC and then back to ABC fixes it (but only for that occurrence)

Background:
- TiVo bought from US, sent direct to Darren King for installation of a tuner & imaging and install of a large HDD (who did a great job, great support afterward, highly recommended!)
- Initial reception problems traced to crap antenna & crap house cabling, fixed with lush new antenna, quad-shielded cable and f-connectors all the way along signal path

If anyone can help, my wife, David Attenborough and I would be very appreciative!

Cheers,
Cods

[Darren King]

Cods,

The intermittent sound loss on one channel only is still related to antenna problems and/or tuning. It is because the Micronas chip (ie the "Mark 2" sound decoder) cannot attain a fully clean sound carrier in the detection phase (ie when the TiVo initially switches channels) and therefore mutes the audio. Given it is intermittent means sometimes you have acceptible sound carrier levels, and sometimes not.

My suggestion is to firstly run palmod_config and fine tune channel 2 a bit, and then if still having problems re-check the antenna install for a balanced reception over all channels received. This is best done with a proper field strength meter rather than "eye and ear" testing if you can get hold of one.

[Cods]

Thanks Darren, I'll give palmod_config a go and tweak the tuning on the ABC this weekend, and see if that does the trick. If not, I'll get the antenna bloke back to do some balancing.

Not a complaint, but the Micronas / Mark 2 tuner seems, in my uneducated opinion, to be a tad, well, picky. As noted, my original antenna hardware / position / orientation / cabling really did suck quite badly, and it seems pretty fair that even though I'm LOS to the Mt Coot-tha Tx'rs, I had a crap signal input to the TiVo. It's worthy of note though that the Sony TV tuner and the dodgy $50 VCR tuner handled it a lot better than the TiVo tuner.

Will do some tweaking and see what results.

Thanks for the swift advice Darren - anyone reading this who hasn't already worked it out: Darren is your man for TiVo work!

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Cheers,

[Darren King]

Not a complaint, but the Micronas / Mark 2 tuner seems, in my uneducated opinion, to be a tad, well, picky. It's worthy of note though that the Sony TV tuner and the dodgy $50 VCR tuner handled it a lot better than the TiVo tuner.

That's a software issue which, unfortunately, I play no part in. On the whole there are very few people experiencing the same problems and I still maintain that in your case, like I said many months ago, it may well be too MUCH signal distoring the sound carrier given your very close proximity to the transmitters. Thinking of which, you were also one of the very first people with the Mark 2 modififcation and I think I remember advising to keep up-to-date with the latest palmod software releases. If you have not done so I suggest replacing palmod.o and palmod_config with the latest versions that also help in this area of sound loss.

Also it is worthy of note that I understand your comment but your dodgy $50 VCR or your Sony does not employ the same components as the TiVo so it is really comparing apples to oranges.

[thomson]

It might also be interesting to see what palmod is doing at the time that these problems occur. If you could do a "cat /var/log/kernel | grep PALMOD" and post the relevant lines (ie the version number and messages around the time that the issue occured) then it might help to determine what could be going wrong. I am more than happy to provide an alternative palmod and make as many changes as required to resolve any issue - and once we determine what/if code changes are required then these could be rolled into the official (OzTivo) version.

[Darren King]

Thanks Thompson. Since all the work was done in tweaking palmod to resolve the initial problems there has been seldom any issues with sound loss, and try as I might I cannot re-create them with my antenna setup. The only lead I can tell you is that every now and then a grotty audi carrier gets detected wrong and this causes loss of sound.

Because it is a check only done once when the channel is changed (that I know of) if it don't detect a clean audio carrier then this problem can result. Is there a way for palmod to test the sound carrier at very regular intervals in an effort to combat this problem without the micronas introducing any annoying glitches into the sound?

Cheers