Big Problems with a Panasonic GT30

Big Problems with a Panasonic GT30

Home Forums Calibration Discussion By Brand Big Problems with a Panasonic GT30

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  • #568
    Anonymous
    Inactive

    Hi all,

    On Wednesday I calibrated or at least attempted to calibrate a GT30. I’ve successfully calibrated GT30s before and got great results. However, this was not my experience on Wednesday! First, my kit – Sencore 403c, i1Pro, Chromapure. With everything set up correctly I set about the greyscale in Pro 1 mode. I got very good results although I could only get about 28 ftl, but that’s typical. The CMS was a nightmare though. Chrompure reported that red and magenta were about 15% too dim, blue was about 5% too dim, but green was 65% too bright, as was yellow at 20% and cyan at 30%. I thought this was extremely odd. Red Green and Blue were pretty much in their respective REC 709 boxes but cyan was pulled toward green, yellow less so. I could correct the primaries’ luminance but only by reducing the color control to 25. I then had to take green luminance down to -30 and pump up luminance on red and blue. However, the secondaries were stubbornly stuck where they were and would not shift. Thinking that all this was very odd I endeavoured to make sure it wasn’t my equipment that was at fault. I rebooted my PC, restarted my Sencore 403c, opened a new calibration session and remeasured. Chromapure gave the same results. I opened another new session – same again. I opened an older version of Chromapure (2.2.3) and remeasured – same results again. I changed my HDMI cable and swapped over my i1Pro for my Chroma 5 and I got the same results again! The same kind of thing was happening in whatever mode the TV was set to – including THX mode. Here are the measurements of THX mode using my i1Pro: [ATTACH=CONFIG]261[/ATTACH][ATTACH=CONFIG]262[/ATTACH][ATTACH=CONFIG]263[/ATTACH] At this point I phoned Panasonic CS who basically didn’t understand what I was talking about and said that I needed to refer to their ISF trainer Piers Clarke (which was difficult because he has been less than complimentary about the THX calibration programme). I described the issue and sent him a photo over my phone of the CMS results in THX mode. He remarked that at a training course he had been at Joel Silver had been unable to calibrate a GT30 for an apparently similar issue. He promised to look into it and get back to my client (who is still waiting for a reply). Any way, after our conversation I thought I’d give it one last try. Now get this… I had changed NOTHING in any respect. When I remeasured ALL the colours came in about 10-15% too bright and the secondaries were right in the middle of their respective boxes! Of course this was easy to correct but this sudden change was completely baffling. I managed to get great results in Pro 1 mode. Thinking that all was now well (though not understanding why) I then proceeded to calibrate THX mode (obviously opening up a new Chromapure session) but making no other changes. I entered the service menu and did my greyscale adjustments and got decent results. Next I ran a measure on the colours and guess what? The same old issue repeated itself! Unfortunately I didn’t have time to finish the job as my client had to leave for an appointment. Has anyone any idea what on earth was happening? Is it my equipment or his TV that is at fault? Has anyone experienced anything similar? I’d be very grateful for your comments as the issue is still unresolved. I have to say that the calibrated modes I left him with (Pro 1 for night and THX for day) looked great regardless of what Chrompure had been telling me.

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  • #2382
    Gregg Loewen
    Keymaster

    hi Julian
    Nice Skyping with you.
    I am not sure what is going on. Perhaps the display is reading RGB vs 422.
    Try measuring off of a DVD and see if you get the same results.

    #2391
    Anonymous
    Inactive

    Julian,

    I have seen this before for the 2011 sets. The display is assuming a SD signal is being received and is decoding it as a SD signal (even though u r sending a HD signal). U can see it when u send the signal and check what matrix is being used in the service menu. I have also noticed that u might be better off sending a RGB signal to the display instead of a YCbCr it gets the identifies the signal correctly. It seems dependant on source and is prominent in the 2011 sets. I believe it is a handshake issue between the source component and the display and somewhere something gets mixed up.

    #2392
    Anonymous
    Inactive

    Thanks. Interestingly, I had exactly the same results this week when calibrating a VT30. I had two sets of everything with me so was able to verify that it wasn’t my equipment per se. Something is happening in the TV. I had put it down to changes I made in the service menu as in both occasions they I believe the issue began to occur after tweaking the THX greyscale, but is it really possible that I’m screwing up the colour gamut if that’s all I’m doing?

    #2407
    Anonymous
    Inactive

    @venkatesh_madhaven 3316 wrote:

    Julian,

    I have seen this before for the 2011 sets. The display is assuming a SD signal is being received and is decoding it as a SD signal (even though u r sending a HD signal). U can see it when u send the signal and check what matrix is being used in the service menu. I have also noticed that u might be better off sending a RGB signal to the display instead of a YCbCr it gets the identifies the signal correctly. It seems dependant on source and is prominent in the 2011 sets. I believe it is a handshake issue between the source component and the display and somewhere something gets mixed up.

    Hi, I thought I’d post an update. After the last visit when things didn’t go too well I bought a new laptop (my old one was really slow) and installed Chromapure afresh. I also purchased an Accupel DVG-5000. I returned to my client yesterday and finished off the calibration with the new gear. I began by taking pre-cal measurements from the TV with the settings I’d left it with. What can I say? Everything was fine right from the start. The greyscale in THX mode was fine and only needed a few tweaks in the Service Menu. The THX color gamut also measured well – with all colours being just slightly too bright. I was able to correct this for THX mode with a minimal decrease in Color setting. So I can only assume that there was some kind of mix up between my Sencore VP403c and the Panasonic TV – exactly as you describe Venkatesh.

    #2411
    Anonymous
    Inactive

    I have found more incompabilities with the new Panasonic series as well (also seen in the V20). The Dune Media Players show the same colour decoding errors (HD being decoded using SD matrix). There is no workaround, sending RGB is the same as YCbCr. I believe the Dune was the Sigma chipset. I am wondering if the issue is compatibility between Sigma chipset and the Panasonic decoding. Not sure if the Sencore used the Sigma chipset.

    The same Dune Media Player with the Pioneer 8G/9G sets did not show the decoding error. So there is something there. Maybe someone close to Panasonic can bring it up with them.

    The Dune Media Player had the problem with last years V20 and this years U30.

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