Adjusting the crt voltage (red) on my sony rear projection tv turned screw and tv shut off and will not turn back on help

The Problem you are having is a Cathode to Grid Short in the Red CRT,When it Shorts the screen will Go all Bright Red and shut Down,The Best fix Would Be to Replace the Defective CRT (GUN)

Check High voltage Block.After replacing ic's (STK convergence ic's) you need to adjust Black&White scale.Turn ALL screen adjustments to min.Turn TV on and adjust screen slowly for each gun (I would start with Red first ) when you came to point that you see red background with white lines across, at that point G2 is too high (that will cause TV to shut down,don't worry just lowered adjustment and turn tv back on) so adjust to proper voltage and do the same for each gun.After that, adjust focus for each gun (again all controls are on High Voltage Block and HVB is mounted on front of your tv after you take speaker gril out) black box with 6 controls' screen RGB, focus RGB .
You should do that in dark room in order to get perfect Black&White scale,when all guns are adjusted properly you will see grey picture.Make sure 'Color" adjustment on your display is down to 0. Another step is convergence adjustment ,Flash Focus etc.If TV stil shuts off after all, your Red picture tube is short inside,take crt pcb from tube,make sure TV is unpluged from power before that, and turn Tv on .If stays On tube need replacment...good luck)

You can try adjusting the Red color output. (Very touchy adjustment)

If you take off the front cover/speaker cover, there should be a access panel. Behind that, there should be a small square black box with 6 screws on it. This is the focus block. (At least this is where most of them are located)

It sounds more like you may need less red in the mix. There is a screw for each color. R, G, and B. Do not mess with the focus screws, just the ones labeled 'SCREEN.'

Go to an unused input where the screen should be dark. Barely turn the red down in a dark room so that the red spot is at the same level as the Blue and Green.

Use an insulated screwdriver and DO NOT TOUCH the focus block and ESPECIALLY NOT the back of it.
Very HIGH VOLTAGE. I found that out the hard way.

Do not turn any of these up too high or damage may occur and the TV may detect a short and shut off.

I have found that if the three colors are adjusted in a dark room to where the 3 color spots (R/G/B) are just barely visible on the screen at equal levels, there is a pretty good color balance.

I hope this helps! Just be careful.

i have a sony rear projection TV, model number kp43t70 screen went black and there was still volume but no pic so I turned it off and now won't turn back on

The adjsutment that you turned down was the G2 voltage to the red tube which is just a temporary fix for a CRT which has a short developing in it. Try turning up the red adjustment again only slightly to see if the red CRT ( tube) will light up
if it does and then the set shuts down its most likely the red CRT which is bad . If it lights up but you get retrace lines but doesnt shut down it possible that its the CR board ( Red CRT Drive Board) which is at the very bottom of the red tube.

I have the same set, I was able to get the set working doing what was suggested on the site I posted below. Unfortunately I have other problems now. These sets are notorious for having failing CRT's (Guns, Tubes). These adjustments "should" help you buy more time out of the set. Sony doesn't make the CRT for these TV's any longer. You can get refurbished ones for around 200.00. Keep in mind there are 3. It is not really worth it, not to mention the time it takes to do the adjustments on the new tubes. If the set won't stay on long enough to do the adjustment, back the appropriate color knob back slightly then try again. I hope this helps.



http://www.somelifeblog.com/2007/06/sony-projection-tv-red-line-repair.html

I think problem is in Protection circuit itself. Protection seems unstable in your tv that's why it doesn't give you chance to diagnose problem.
Try to isolate protection command and check tv.
Its an idea and hopefully it will work.

Replace HV block when self-diagnostic LED blinks 8 times =
Sony part # 8-598-955-32....if that doesn't cure it, the red CRT
would be next..................T.

Mine just did the same thing.  Except for it was green instead of blue.  The service manual states 8 flashes from the light stands for an overvoltage.  After reading the manual for a bit I realized the bottom row of 3 adjuster screws from behind the speaker grill adjust the output for the red, green, and blue colors.  BEFORE OPENING ANY TV OR MONITOR PLEASE KNOW THAT THE VOLTAGE INSIDE CAN KILL YOU EVEN IF UN-PLUGGED so please be careful and only adjust what is mentioned here.  I un-plugged the tv, removed the grill and the board covering the internals, and carefully turned the 3 adjustment screws all the way down.  I then waited about 10 minutes (don't know if this made a difference).  I turned on the tv, turned the channel to an auxilary input (for a black screen), and slowly raised each of the 3 bottom screws one by one up clockwise until i could see a faint green, blue, or red line (depending on the screw), and then turned each one back a hair until the screen was black again.  Only adjust one at a time, the order for colors are blue, green, then red from the left.  I hope this fixes your problems.  Be careful when working inside a tv,  I suggest not using a screw driver to adjust the screws due to the possibility of it slipping and someone getting hurt.

cold solder on yhe red crt drive.u can find it at the back of red crt try to solder cold joint..or much better if u can refresh all the solder joint. also ,a corrosive terminal of red yoke might also be the culprit. hope this help u...