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First, try a hard reset.
You must unplug the power cord (turning off the set or the strip will not do it) for a couple of hours, then try again.
This will sometimes correct the problem
When it blinks off: Does the raster go dark or just the picture and the raster remain? If the raster goes dark when it blinks off it means there is a loss of high voltage to the picture tube. High voltage repair is expensive. It may be a failing flyback transformer that is functional inside the horizontal deflection circuits. If the raster stays on and you just lose video (picture information) then it may be a simple intermittent IC chip in the video board area. It may require a technician to determine which IC and how to replace it or the parts associated with it, but probably not terribly expensive to repair.
The vertical ICs on this particular model have by now bad grounds. You will have to resolder this, and check any and all grounds on ICs mounted on heat sinks! Bad grounds are common and plentiful. Good Luck and thanks for asking!
check the high voltage with the screen control turned up high where there is no raster. suspect problem within the video circuit where there is no high voltage or defective picture tube.some time when the screen is black and the screen control advanced,you can see if the tv has video or vertical or horizontal problems on the screen.service the high voltage circuit if there is no raster or high voltage is seen.no raster can be caused by the no heater or filament in the CRT.----
a defective picture tube can cause many problems, such as, poor brightness ,missing colors,intermittent picture,poor focus,a single-colored raster,arching in the gun assembly,retrace lines in the picture,negative picture,chassis shutdown,noheater or filament lit and no raster to name a few.an open filament or heater can cause no picture or no raster symptom.a defective CRT can have an extremely bright screen.loose particles of the cathode element can lodge between the grids and cause an intermittent black and white picture. simply tap the ends of the CRT gun assembly and notice if the picture begins to flash off and on.----
with a leaky picture tube after turn on the raster dims and get extremely bright.a dim picture with no green in the raster can result from a bad green assembly. a heater-to-cathode short can cause a raster to change colour or a result in no raster at all.replace the picture tube if there is severe arching in the neck of CRT.
excessive brightness with retrace lines and a vertical collapse to a thin line can be caused by a bad coil on the neck board of the picture tube.rejuvenate the picture tube when there is very bright green screen.
check for the resistance change on the resistors of the CRT neck board for an excessively bright picture with retrace lines.excessive dust inside the CRT spark gaps within the picture tube socket can cause the very bright raster and the chassis shutdown.a defective video amp,luminance buffer,or reference transistor can cause a bright picture with retrace lines.
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first you check the signal cable continuty by multimeter then correct it if faulty .if ok then give -ve click at red cathode on crt base in on condition if red raster comes on screen then red cathode is ok same thing for green and blue cathode if green cathode do not shows green raster after -ve click then crt is faulty then give -ve click at R point at color raster ic which has heat sink if red color comes then ic is ok same thing for green and blue if ic is faulty then replace it if not then check bipolar capacitor if faulty then replace it
check Vertical IC out (LA78..) and resistor voltage supply from flyback transformer to this ic. Check the STR main power supply(and resistor near, change value), some times seems good out main board,but in operation not good
What you have described there is a classic example of the jungle IC failure. Ic301 Sony p/n 8-752-101-04. A pic with no color, and lines or grainy texture in the picture. Not a project you want to tackle if you don't have the proper soldering equipment or skills. And not a costly one at a good repair shop.. Only real hurdle is getting that heavy monster into the shop.
To answer your question, yes what you described there is raster. Even the salt & pepper looking screen with no real decernable image is described as raster. In fact any image generated on the CRT is raster.
And yes, these sets are prone to solder joint problems, usually ring cracking in circuits that generate the most heat.