Strange AV AMP problem.

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Ultra Violent

Original Poster:

2,827 posts

275 months

Thursday 17th September 2009
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I currently run Cable (Virgin), XBOX 360, PS3, and Blue Ray (Denon BT2500) through my Denon 4308 AV AMP to my LCD i.e. the Denon 4308 does the HDMI switching and feeds HDMI to the LCD.

The other night the picture dropped out and wouldn't come back on. It has in the past briefly dropped the video signal, but it would return in seconds. At this stage I thought it was my Virgin cable box and had it replaced. Signal still dropped but I thought it was less frequent.

The other night it dropped and didn't return. Sound still working, though. So I assumed the video boards had failed. To test this I switched to the XBOX, which worked. DVD works, PS3 works. So at this stage I assumed it was HDMi 3 (Cable input) had gone down on the AMP. So I plugged the XBOX into HDMI input 3 (which was the cable input), expecting it to confirm a failure on HDMI 3 (as the XBOX input was previously working). But no, it worked fine. So then I assumed it was the HDMI cable feeding the AMP from the cable box, so swapped that for one that was working. Still no joy. So then I assumed it was the cable box and so wired it directly to the LCD (i.e. not through the AMP) expecting it to show a faulty set top box. But no, it worked. So now I am completely lost as to what it could be. Only thing that makes sense is if Vigin (cable provider) has released an new video standard that my AMP doesn't understand (but my LCD does).

Any help much appreciated.

thegreengoblet

1,040 posts

222 months

Thursday 17th September 2009
quotequote all
Is all your equipment HDCP compliant?

Ultra Violent

Original Poster:

2,827 posts

275 months

Thursday 17th September 2009
quotequote all
Its all relatively new stuff. It would have to be the AMP that wasn't HDCP compliant, and I know it is. Plus I have the latest firmware.

thegreengoblet

1,040 posts

222 months

Thursday 17th September 2009
quotequote all
Another thing to look at is your power supplies. Is all of the equipment being powered from the same extension lead or from sockets on the same ring main? I had a funny ground issue once when one piece of equipment was being powered from a seperate socket on a different ring main (I have 2 different ring mains in my office). Basically caused a sound interference. Dunno why as they come from the same source?? Anyway. It's also worth checking that all your plugs are wired ok i.e. no loose earths.

headcase

2,389 posts

223 months

Friday 18th September 2009
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sounds like a handshaking issue, try turning the resolution on the cable box down and see if you can get it back. I take it you have tried resetting everything? HDMI is a wonderfull thing :P

Ultra Violent

Original Poster:

2,827 posts

275 months

Friday 18th September 2009
quotequote all
Ah, well done! You were close. If i turn the upscaling on the AMP down to 1080i rather than 1080p we have the Picture back. This is actually an output from the cable box so technically not upscaling. However 1080i->1080p just doesn't work for the cable box. All my other HD devices output at 1080p so no upscaling required.

Ultra Violent

Original Poster:

2,827 posts

275 months

Friday 18th September 2009
quotequote all
Yep, turns out the Scaler is buggered. If I avoid scaling, all sources work fine, even if they are naturally 1080p (obviously as it is the scaling which is at fault).