Blank screen audio ok. Picture tube has a line only going up and down

Hi Jaime.
Well it seems you have a dry joint or loose connection somewhere
in or to this receiver. Faults of this nature may at first seem straight forward but they can be very frustrating and often send you on a wildgoose chase.
The most valuable tool you posses will be patience and if you are still reading this then this virture in you is onfirmed. So let us continue.
We first need to narrow down the suspect area where the problem may be hiding. You say the picture is intermittent so I'm assuming
you still have sound. If you still have a raster (brightness on the screen) then the line oscillator, line drive, line output and EHT circuits are all functioning and your attention should be drawn to the composit video circuits in particular dry jionts on the rca video input socket your a/v cable is connected to (it's the yellow one)..
If you have only a blank screen did the disappearing picture
go to a horizontal line across centre of the screen just before going blank. If yes then the problem probably lies in the
frame output stage. Resolder all pin connections to the frame output ic (even if they look ok) and all pin connections on the flyback transformer (Line output transformer to some of us).
If the picture fades away rather than flashing off then look to see if the tube heaters are still glowing, If not resolder the heater pin connections on the tube base socket and all pins on the flyback
transformer. Stll haven't cured the problem ? Have a nice cup of tea before poceeding, you've earnt it by now.
OK once more into the breach dear friend, it's time to get violent
with this stubon beasty and start tapping the circuit board to find the most sensetive area and resolder all the joints you can find within a two inch radius of this point. The most common points for dry joints to occure are in the power supply, line output stage and
frame output stage (vertical stage to even more of us)
Good luck Jamie. Best regards from Vintie

The picture tube is right on the edge of working with the set's AKB, or auto cathode balance. All Sony tube TV's use AKB. AKB is a circuit that attempts to compensate for aging of the picture tube (among other things), and if the tube isn't conducting enough (due to age), it will intermittently blank the screen or, in severe cases, not allow the picture to come on at all. But if you are comfortable taking the back off of the set and making a minor adjustment, you can probably restore the picture for a while longer. Take the back off, turn the set on to a blank channel (receiving snow). You will see a large gizmo with a thick red wire coming out of it going up to the glass on the picture tube. That's the high voltage (a.k.a. flyback) transformer. On this transformer will be a small knob labeled "Screen." If you turn this control ever-so-slightly counterclockwise, the screen will blank off immediately. But if you turn it just a bit clockwise, it may fix your problem. Don't go too far with this control, just enough to make it work. This is DANGEROUS FROM HIGH VOLTAGE, so make sure you have a qualified tech help you do this.

Sony sets have several protective circuits that blank the screen if something happens that might damage the picture tube. One of the more common causes is trouble in the vertical output circuit. Given the age of your TV (the XBR models have been around a while), this might also be a symptom of a picture tube starting to fail. Most of these sets have circuitry (called AKB) that adjusts the color drive signals to the picture tube to keep them balanced. If one of the colors is enough out of range the screen will blank. It might be the tube itself, or failure of some part in that AKB circuit. The set might also have defective parts in the input switching or video processing stages.

Unfortunately, I can't suggest any place you might look if you want to try repairing this on your own. This kind of trouble usually needs to be diagnosed and repaired by a professional TV technician who has the service information to track it down.

Hope this has been helpful. Thanks for using Fixya!

TV Parts Universal TV Stands DLP Chips ShopJimmy Your T-Con board is toast. You can get another from here.

It's normal for Sony TVs to have a delay in the video. The screen stays blanked until the circuitry in the set has decided that the picture tube is operating correctly. The screen can remain blanked due to a number of causes. Bad solder connections or components in the vertical output stage are common. Also, Sony sets automatically adjust some tube voltages. If the tube has aged enough or component values in the set have changed and the adjustments don't keep the values in the correct range, the screen will blank out. Intermittent components or connections in the set's video stages or source switching can cause screen blanking. Unfortunately, this is one of the tougher Sony problems to troubleshoot. It usually requires the schematic and an oscilloscope to track down.

If the screen works for a short while and then completely fails once the TV warms up you have a problem with the main unit video board or the LCD control logic board. Most often if the picture cuts out but audio continues to work the logic board is over heating and should be replaced. However if the picture cuts out and audio shuts off as well then its your video input board.

Try unplugging for 36 hours. I had the same problem but with no sound and picture

Hi, u have clearly mentioned that u are able to hear the sound from ur television. So the audio port of ur tv has no problem. The problem is that the picture tube of ur tv has damaged totally. Video output port has lost its ability to display on screen. If u are in a option of repairing ur tv its better to get a new picture tube or else if u opt for purchasing ur new television its well and good. but the cost for replacing ur new picture tube costs more.

Please check 1000 volt at CN703 on C board fixed on picture tube.

could be down to the tube in side the tv that is what create the picture