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Old 07-18-2021, 01:39 PM   #1
jkb242
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Default Vizio M3D470KA 3d 47” tv no color

This set works fine in every way except there is no color. Off air and HDMI sources all work but no color. The model number is M3D470KA obviously no schematic. The goal for this set is an HD monitor ONLY. I have never encountered this issue in all the sets i have worked on but in general, believe the loss of color is associated with the HDMI controller chip. I don’t believe in just changing parts so I would very much appreciate comments about troubleshooting this issue. In older analog sets I would be looking at the color burst oscillator but not sure this is where to begin investigating a chroma issue.

Thanks so very much.
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Old 07-18-2021, 06:47 PM   #2
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Default Re: Vizio M3D470KA 3d 47” tv no color

What about the osd menu? Are the on air channels via the coax in color?
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Old 07-20-2021, 09:22 AM   #3
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Default Re: Vizio M3D470KA 3d 47” tv no color

Thanks for your reply, they are not.
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Old 07-20-2021, 09:26 AM   #4
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Default Re: Vizio M3D470KA 3d 47” tv no color

Sorry I did not answer your question regarding the onscreen menus. Yes, since these are generally bitmaps with overlays, they show up in color.

It seems to be with video decoding from inputs HDMI and off air.

Thanks!
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Old 07-20-2021, 12:20 PM   #5
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Default Re: Vizio M3D470KA 3d 47” tv no color

I think replacing motherboard is one of the only solutions to this problem.
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Old 07-20-2021, 02:56 PM   #6
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Default Re: Vizio M3D470KA 3d 47” tv no color

No way am i going to buy a main board, its not worth that. This can only be a chip or supply missing to the chip which is no big deal. I do micro soldering and have the skills just hoping someone else here is familiar with where the chroma is recovered. I think its in the HDMI CHIP but was hoping for familiarity with HDCP AND chroma recovery. Thanks
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Old 07-20-2021, 05:21 PM   #7
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Default Re: Vizio M3D470KA 3d 47” tv no color

If the on air channels are also black and white, then its not the HDMI IC.
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Old 07-21-2021, 06:27 AM   #8
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Default Re: Vizio M3D470KA 3d 47” tv no color

Thats is my suspicion as well and thanks for confirming my suspicion.
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Old 07-21-2021, 09:12 AM   #9
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Default Re: Vizio M3D470KA 3d 47” tv no color

Quote:
Originally Posted by jkb242 View Post
Thats is my suspicion as well and thanks for confirming my suspicion.
doesn't this tv has component video?


https://www.ebay.com/itm/33254650570...gAAOSwWZtgylmt

Last edited by ivtec; 07-21-2021 at 09:20 AM..
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Old 07-22-2021, 08:03 AM   #10
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Default Re: Vizio M3D470KA 3d 47” tv no color

Thanks for the link to this replace board. Indeed less than i’ve seen but I’m confident i can replace the HDMI surface mount. It does have component video as well as composite but for preferred using an HDMI single connection opposed to the 5 connection required with component including audio of course.

Thats an interesting approach and thanks for that suggestion but without even a block diagram of the video chain for this set, not to mention a schematic, I’m not familiar with where the chroma processing would occur if outside the HDMI processor/switch. I’m thinking this would be right at the input to the LCD driver matrix but would appreciate any input you could share.

Thanks again!
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Old 07-22-2021, 08:38 AM   #11
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Default Re: Vizio M3D470KA 3d 47” tv no color

You don't have a block diagram or schematic, we don't even have photos.
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Old 07-22-2021, 09:49 AM   #12
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Default Re: Vizio M3D470KA 3d 47” tv no color

Quote:
Originally Posted by jkb242 View Post
Thanks for the link to this replace board. Indeed less than i’ve seen but I’m confident i can replace the HDMI surface mount. It does have component video as well as composite but for preferred using an HDMI single connection opposed to the 5 connection required with component including audio of course.

Thats an interesting approach and thanks for that suggestion but without even a block diagram of the video chain for this set, not to mention a schematic, I’m not familiar with where the chroma processing would occur if outside the HDMI processor/switch. I’m thinking this would be right at the input to the LCD driver matrix but would appreciate any input you could share.

Thanks again!
https://www.service-manual.net/?down...service-manual
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Old 07-23-2021, 07:45 AM   #13
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Default Re: Vizio M3D470KA 3d 47” tv no color

Thanks for the link to the schematics. I have purchased from folks like this before and received worthless unreadable prints. Fool me twice…. But thanks for the suggestion.
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Old 07-23-2021, 07:47 AM   #14
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Default Re: Vizio M3D470KA 3d 47” tv no color

Quote:
Originally Posted by diif View Post
You don't have a block diagram or schematic, we don't even have photos.
Would a photo help? What photo would be helpful?
Thanks.
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Old 07-23-2021, 08:02 AM   #15
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Default Re: Vizio M3D470KA 3d 47” tv no color

Quote:
Originally Posted by CapLeaker View Post
If the on air channels are also black and white, then its not the HDMI IC.
So you are sating the recovered video from the tuner has a separate chroma path to the LCD video driver? Wouldn’t that mean the HDMI chip is bypassed for video demodulated from the tuner? That would be interesting to troubleshoot but since there is a good video signal being delivered to the LCD driver, then it would seem there is a separate chroma injection as well. The transmitted RF signal is all digital which captures chroma information as well. Unless the signal is converted to analog, as in the former analog NTSC format, where a burst oscillator is used to reinsert and demod the transmitted chroma signal. Correct? If there is an analog conversion in HD sets to recover video, I would be appreciate knowing this.

Thanks!
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