Red lines on Sony KP51HW40 Rear projection TV

Before you break down and have the tube repaired, it could be a faulty or mis-adjusted screen setting. These projection TV's have three individual CRT tubes. Each tube has a FOCUS and SCREEN adjustment on a block inside the TV. I have the 57" model of the same series of TV's and just had to do some work on it. If you remove the front panel and the small wooden panel behind that, you should see a block with 6 screw adjustments. On my TV the set on the right was for the red tube. The top screw adjusts focus and the bottom adjusts screen. Focus (as the name implies) makes the screen go in and out of focus. If your TV isn't blurry then don't touch the top knob. The bottom knob is SCREEN. This knob adjusts the brightness (power) of the tube. If this knob is turned up too high, red lines will start to develop across the screen. At first, they'll only be visible when the screen is black, but if you keep turning it up they'll become very visible. If you turn it up even higher the whole screen will become red. Running it at full power (the whole screen being red) will cause an electronic lockdown and shut off the TV (at least it did with the blue tube, I was playing with the knobs and accidentally made it turn all blue then click off. I waited a few minutes, turned the knob down, then turned the TV back on and all was fine again). What you need to do is simply turn down the bottom right knob until the red lines go away. Put the TV on a blank screen (all black, just having it on an unused video input works great) and then slowly turn down the lower right knob (red screen knob) until the lines go away. Then put the TV on a picture to make sure the red is still visible. Finally, turn off the TV and turn it back on and use it for a while (don't put it back together yet, but make sure the front panel buttons and LED's are connected). I had a problem where the TV gave me an error code 5 (AKB error, shown by the Standby light flashing in sets of 5). After some reading and experimenting I found out that it was giving me this because I had set the red TOO low. I turned it up until the lines showed up and then turned it just slightly until the lines just vanished (but no further down) and then reset the TV by going to the system menu (Display, 5, Channel +, POWER while the TV is off) and then pressing 8 then Enter (Factory Reset). If you simply follow my advice (don't turn the knob down any further than necessary, just to the point that the lines don't show) then you shouldn't get the error at all.

Yeah, seen that more times than I shoulda in the last 4 years. The red picture tube has a cathode to heater short. That means it's no good. That red picture tube is no longer availible. But all is not lost. There is a company that rebuilds those tubes reasonably. Most reputable tv shops will know this. The ones I've done cost around $450 out the door. One minor hitch is that with all the shipping involved the job usually takes about three weeks. That can be expidited but then the price goes up.