Riddled TV Repair Forum

jpamp · Joined: 30 Jun 2008 Posts: 3

Long time reader first time poster.

Hello i have a 2.5 year old jvc rpt #av48p776. i have two questions about problems i am having.

1. This tv is supposed to have HDMIwith HDCP support, but i finally bought a Toshiba A3 HD-DVD player and when using the HDMI port with a HD-DVD the screen goes blank. Video works with component, just not over HDMI. I have updated the player to firmware version 3.0 but that did not help. JVC tech support said maybe the HDMI board is bad, but non HDCP content displays fine. Anyone have any suggestions as this stinks since i also just bought a HK AVR 247( which does not seem to like SD or HD content over HDMI to the TV) specifically for use with HDMI as well.

2. I was checking out the service menu self check on the advice from a friend to see if it showed any errors on the HDMI port, and i do not think i touched anything but now i see a small green plus sign or crosshair in the center of my screen, it does not mater what input i am on it is always there. Do you think i must have hit something to turn it on, i have not noticed it until i had these HDMI issues? Anyone know how to turn it off? I also had an error show up in the self check for the AIO and the IP areas they both said NG and then a number. Does anyone know what these codes mean or have a list with the NG numbers as well?

thanks,

Google

Jesse Mack · Joined: 22 May 2008 Posts: 600 Location: The Last Frontier

Just about all HDMI tv's within the last 4 years have HDCP (High-bandwidth Digital Content) protection. This feature is to prevent YOU from trying to copy the content.

That being said, there are a couple of things that come to mind. First: Have you had the back off of the set? If you have, you very likely will have to reset the HDMI to get it to work.

I resist telling you to enter the service menu as it is very easy to make things worse if you do not know what you are doing. However, since you know how to enter it, do the following to reset all error codes and the HDMI circuits.

After entering the service menu, enter the #4 key on the remote to enter the self test.
While in the self test, push the Power key on the remote.
This will reset the HDMI and possibly the error you may have inadvertently entered. (the green crosshair sounds like you entered the geometry or convergence alignments. Unless you know what you are doing this is not a good place to be as the results can make a mess of your picture.)

Question: Does the sound work using the content protected HDMI?
Question: Does the on-screen display work when the screen is black?

If the answer is yes to these questions you either have some bad connections on the surface mount connectors that are on the digital pcb or the digital pcb is most likely defective. You will have to remove the Digital pcb to examine the connectors. You will have to have the shields removed, a Loup (magnifying glass), and a bright light to examine the connectors. A new board costs $185.00 Wholesale at a distributors and a $100.00 core charge.

To access the the digital pcb you do have to remove the back and the HDMI will have to be reset.

I hope this helps.

Jesse

jpamp · Joined: 30 Jun 2008 Posts: 3

Thanks for the info.

The back was never off on the tv (that i know of since buying it new in 2005). i have tried to reset the tv using the self check with no luck (that was all i looked at in the service menu originally).

I will have to check to see if the sound works over HDMI through the tv as i have only tested the sound through my receivers with optical or hdmi. That does work while the dvd is playing. When the protected content starts the screen goes black but i can still see the JVC menu's and OSD such as the input name etc.

One more thing that i was discussing with JVC Tech support is that it must be working for part of the HDMI handshake as the hd-dvd player is supposed to display an error message if it can not get a signal over HDMI, which it does not display. The tv screen also switches from black to green for a split second every time you try to switch chapters over the HDMI input. Standard deffinintion dvds play fine as well as the dvd players setup menu over the hdmi as long as it is not connected through my HK AVR 247 receiver.

The problem with the green cross actuall looks more like a tiny 1/4" diamond on the screen as i look at it more it is on every input and not very noticable from our seatiing area unless you are on a blank input or something where the whole screen is a solid color (like a lake on a weather map). It is exacttly in the center of the screen vertically and horizontally. And i know think that something else is going and that it has nothing to do with me trying the self check.

thanks again for your ideas.

you do not happen to have a copy of the service manual for this model do you?

jpamp

Jesse Mack · Joined: 22 May 2008 Posts: 600 Location: The Last Frontier

I do have a copy but I cannot release it due to copywrite and propritory restrictions place on me by the manufacturer. Another thing, The field servicers like me do not have access to the schematics of the digital pcb anyway and even if we did the micro's do not have legs and are point-solder mounted by a VERY expensive machine. Also know that the micro's, unless purchased in very large quantity's, cost more than the complete circuit board.

Since it has become obvious that the green is not a convergence problem, and it is exactly in the center of the screen, I would suggest that you remove the screen and look directly into the crt's of the blue and red (while the set is on, and in a blank white screen if possible) to see if there has been a burn or pixel issue on these two crts. (it will be a black spot in the exact position on either the red or blue crt's as your resulting color is left at green.) If there is a burn or pixel issue, the only correction would be crt replacement and if it is not too noticeable it may not be worth it.

I have had several bad digital pcb's causing your symptom. but before running out and buying one I would definately use the loup and check out the connections on the connectors. (they are VERY tiny surface mount connections.)
Just remember, if you take off the back you have to reset.

Good luck

Jesse

jpamp · Joined: 30 Jun 2008 Posts: 3

Hello thanks for the help my tv is now fixed it was a bad hdmi board and a burnt spot on the blue tube.

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