Riddled TV Repair Forum

dennyg · Joined: 10 Nov 2008 Posts: 4 Location: NE Ill

Sony KDL-V40XBR1 loses cable card authorization

My 3 year old Sony 40" LCD TV with cable card has a weird problem. It randomly loses the cable card channel authorization and the screen goes blank and says "not authorized." I first thought it was the cable card and had it replaced but it still happened. I found that when it goes out if I recycle the power with the line cord - not the power switch - it will again work OK for awhile until it again randomly goes out. It is now going out several times a day.

I have the service manual but it doesn't tell me much. If I had a clue what part might be the problem I could try replacing it.

Anybody have any ideas?

Thanks, denny

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kuhurdler · Joined: 28 Dec 2006 Posts: 2879 Location: Overland Park, KS

I'm not certain this is your problem, but I would check into the signal strength of your cable. It may just be a weak signal. its harder to tell when you're receiving a digital one.

dennyg · Joined: 10 Nov 2008 Posts: 4 Location: NE Ill

Thanks for your reply. Signal strength is high according to the instrument the cable folks used to check out the system when they replaced the cable card.

The TV has a linux operating system and I'm assuming that on bootup it loads the authorizations from the cable card into memory. It seems as if cycling power reloads the card data. But this is just a guess.

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

You might check the diagnostics display on your TV. Just because you have think you have good signal strength does not mean you have good signal.

Check the In Band (FAT) on the diagnostics page of the tv.

If you have errors (normally = 0) and the signal to noise ration is low (20~27DB)(normal = around 34) amd the tv tuner amplification = 55 you have bad signal.

Don't know where you came up with the linux idea. I have never heard that said, even by the trainers from Sony. I believe you will find that the operating system is a very discreet propriatory system control microprocessor system that run's on firmware, not software and can be upgraded via USB port.

You could have a bad "Q" box, but the diagnostics are too deep for this forum.

But, what do I know, maybe you are right and all TV's can talk linux.

Jesse

dennyg · Joined: 10 Nov 2008 Posts: 4 Location: NE Ill

Here is what I see on the diagnostics page with everything working. I'll check it again the next time it goes out if that is any help:

In Band (FAT)

Phy. Ch: 0
Freq. (KHz): 543000
Modulation: QAM256
Status: Lock
Errors: 0
SNR (dB): 36
AGC (%): 37
Interleaving: I=128, J=4

I believe linux was mentioned on the instruction sheet that Sony sent along with a firmware update on a USB chip - I likely read far too much into it.

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

That looks good,

The "Q" box does the following.
Channel maps and decodes.
Stores the Unique identifier from the cable company.
Inputs are: CATV air input, analog air input, memory stick input, pod/cablecard/PCMCIA input, USB port input.

Within the Q box: OOB,Tuner,VSB,QAM,IF Pack, POD controller, Digital micro signal processor, LVDS.

Outputs are: Analog CV from tuner, Audio, Analog Audio, Analog Video Y,Pb,Pr ,Data to TV Micro, Digital graphics, Analog graphics .

This is all within the "Q" box and has been know to do some very strange things. Unfortunately, the "Q" box is Very Expensive and if you replace the "Q" box you will have to reactivate your cablecard.

Q box cost = $250.00 + $920.00 Core charge.

Digital Processing: Ain't it great

Jesse

dennyg · Joined: 10 Nov 2008 Posts: 4 Location: NE Ill

Thanks so much for your help. What you describe - the "Q" box - certainly sounds like a likely culprit. With the cost, it seems to boil down to two choices - either live with it or buy a new TV, preferably one without a "Q" box.

Thanks again, denny