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PostPosted: Sat Oct 06, 2007 2:28 am 
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Joined: Tue Dec 20, 2005 3:35 pm
Posts: 57
Location: Seattle, WA
R5F27:
2.8GHZ Celeron
1GB RAM
PT890T-A (MB)
nVidia GeForce 7600 GS, 256MB, PCI-X
300GB Drive


Very sad regarding this one. I bought these PVR-150s new, and over time SOME CHANNELS have become unstable to the point of being unwatchable|recordable. At first, the upper channels suffered (channel 99), and now thay are becoming crappy throughout, even the lower channels (like 4). The main symptom is jittery video, looking like lack of vertical syncing.

Is it just me, or is the quality of the Happauge tuners over-rated because thay (MAY) use cheap crystals when building these systems. All tuners need to have an accurate time base (usually via crystals) and if the crystals drift off frequency it could lead to instability.

I have an electronics background, I've switched cables, checked signal levels, and nothing seems to help...

When I run:
root@mythtv:~# v4l2-ctl --all |grep Sig
Signal strength : 99%
root@mythtv:~#

There appears to be plenty of signal, even on channel 99, but I still get crappy video.

I've futzed with the various TV->playback controls, XV, bob, etc... I've even tried the manual channel scanning vice using the cable lineups. I've changed the AGP buffer size (in CMOS).

Oddly, both tuners show the same symptoms, which logically points elsewhere.

The cable is good because the Comcast tuner gets channel 99 perfect, and I've even bypassed the splitters and ran the direct cable directly into the PVR-150s, with the same result. I've also moved the PVR-150s around the chassis to different slots.

Is there any way to "reset" these tuners, reload the firmware, and "jolt" them back into a new state? It's like the AFC (automatic frequency control) is not set, but they must be with 99% signal.

Now I HAVEN'T tried putting them into a windows box and see how they work with the latest driver. Maybe that would fix them.

Ideas? Or should I just buy a new PVR-500 and offload these on craigslist [grin].
________
GROUP INSURANCE ADVICE


Last edited by mz4wheeler on Thu Feb 24, 2011 1:17 am, edited 1 time in total.


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PostPosted: Sat Oct 06, 2007 8:43 am 
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Joined: Thu Mar 02, 2006 5:42 pm
Posts: 410
Location: middleton wi usa atsc
Did this get noticeably worse with R5F27? Have you tried changing the capture resolution to 720 x 480 as outlined in tjc's Hints and Tips under "known issues"? Also turning off VBI in "Myth Setup"? I had a lot of jumpiness and vertical tearing until I did that.


Last edited by jzigmyth on Mon Oct 08, 2007 6:29 am, edited 1 time in total.


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PostPosted: Sat Oct 06, 2007 9:26 am 
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Joined: Sat Sep 02, 2006 9:17 am
Posts: 359
I realize this may sound like total BS, but try replacing your splitters.
I eventually called the cable company to come fix my awful picture, and all they did was replace my old, but very high quality splitters with whatever they had on the truck. The difference was immediate and unbelievable. I was downright unwilling to believe that splitters "wear out" as the repairman said, but I can't deny it worked.


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PostPosted: Sat Oct 06, 2007 10:26 am 
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Joined: Tue Jan 18, 2005 2:07 am
Posts: 1532
Location: California
Quote:
The cable is good because the Comcast tuner gets channel 99 perfect, and I've even bypassed the splitters and ran the direct cable directly into the PVR-150s, with the same result. I've also moved the PVR-150s around the chassis to different slots.

Comcast has a technology called Analogue Digital Simulcast (ADS). What they do is re-transmit all of the analogue stations in digital format at SD resolutions. Many of their set top boxes will automatically tune to the digital version of a channel when you select it. So when you look at channel 99 on the comcast box, you may be looking at the digital version, rather than the analogue version that the Hauppauge card tunes in.

An interesting test would be to connect the cable that goes into the PVR-150 into the analogue tuner of your TV set and see what it looks like...

Marc


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PostPosted: Sat Oct 06, 2007 11:07 am 
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Joined: Tue Dec 20, 2005 3:35 pm
Posts: 57
Location: Seattle, WA
Thanks for all the responses. Trying to encapsulate all the suggestions:

It's not the spitters because I directly connected the cable into the PVR-150 tuners, with the same result.

I DID read the tips and tricks, but I noticed this deterioration prior to upgrading to R5F27. In fact, I was hoping that it would cure it [grin]. I will look more closely to that document and see about changing the resolution.

I AM using VBI, so I will try to turn that off. However, we really like the CCs, it helps my children learn to read when that are watching buzz lightyear [grin].

Also, excellent suggestion regarding testing with another analog tuner. I did not know that Comcast used this ADS technology. My Comcast tuner is one of those tiny digital versions.

I'll try all these suggestions as soon as possible and get back to you.

Thanks!

Mike


marc.aronson wrote:
Quote:
The cable is good because the Comcast tuner gets channel 99 perfect, and I've even bypassed the splitters and ran the direct cable directly into the PVR-150s, with the same result. I've also moved the PVR-150s around the chassis to different slots.

Comcast has a technology called Analogue Digital Simulcast (ADS). What they do is re-transmit all of the analogue stations in digital format at SD resolutions. Many of their set top boxes will automatically tune to the digital version of a channel when you select it. So when you look at channel 99 on the comcast box, you may be looking at the digital version, rather than the analogue version that the Hauppauge card tunes in.

An interesting test would be to connect the cable that goes into the PVR-150 into the analogue tuner of your TV set and see what it looks like...

Marc

________
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Last edited by mz4wheeler on Thu Feb 24, 2011 1:17 am, edited 1 time in total.


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PostPosted: Sat Oct 06, 2007 11:38 am 
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Joined: Tue Jan 18, 2005 2:07 am
Posts: 1532
Location: California
Quote:
My Comcast tuner is one of those tiny digital versions.

I'm fairly certain that those tiny boxes are actually ADS tuners...


Marc


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PostPosted: Mon Oct 08, 2007 1:17 am 
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Joined: Tue Dec 20, 2005 3:35 pm
Posts: 57
Location: Seattle, WA
jzigmyth wrote:
Did this get noticeably worse with R5F27? Have you tried changing the capture resolution to 720 x 480 as outlined in tjc's Hints and Tips under "known issues"? Also turning off VBI in "Myth Setup"? I had a lot of jumpiness and vertical taring until I did that.


Bingo! :D That did the trick! Changing the resolution from 480x480 to 720x480 completely fixed the problem... I guess I won't offload those PVR-150s on craigslist [grin].

Seriously, it seems that *IF* you have a PVR-150, then it is ESSENTIAL that this be set to 720x480. I wasn't even aware of how important this was. I've been running this for 2 years w/o changing any of these settings in:

Setup -> TV Settings -> Recording Profiles -> ALL of them

Maybe during the boot process this should be made the default?

Thanks to all who helped on this. Now I can finally watch the "Red Green Show" w/o the jitters, because it only comes on channel 99 [grin].

:D
________
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