RCA mod# F31317 (svc# F31317-YX53), Chassis# CTC203CA6 This is another try for any other possible checks or solutions. One prior submitted solution to check several resistors on the CRT board failed to find any problem. I am still open for any suggestions. Is it just a boat anchor or a repairable unit (within reasonable costs)? Does anyone have a schematic? Unit is approx 6 years old (per prod. date). Lost blue in picture. Picture has a sepia-like appearance. Reds are still good and green is there also. No noises occurred and there was no indication of a failure prior to the loss of blue in picture. Found service mode label inside case. Checked the blue control parameters. No adjustment can be made to the blue switches that have any effect on picture color quality. The red and green can be adjusted. The first 3 parameters are codes and each one shows code 24. I cannot find any info to define these codes. Checked the circuit board attached to the rear of the tube for cracked solder joints. No cracks visible but I touched a solder iron to each to attempt a possible fix to no effect. Checked all plug-in connections for tightness and cleanliness, NPF. I have not removed the main board to check for solder joint integrity. There are no visible damages or failures on the main board.
This symptom is characterised by the loss of one or two primary colours. this symptom can be classified into three cases: 1) loss of red colour, 2) loss of colour blue,3) loss of green color. this symptom may be caused by a trouble in the colour demodulator, in the color amplifier or in the colour subtraction amplifier circuit. in your case loss of blue colour. this is a very complicated problem that you need some special test equipment like oscilloscope and color pattern generator in order to trace the signal. tune the receiver to a color broadcast station(a colour bar generator can be used to transmit a colour signal to the set). check the Z-axis demodulator, z-axis amplifier and the B-Y output circuit for the chroma signal. observe the signal process with an oscilloscope. if the color signal is not present use a VOM to locate the defective component in any of the above circuits. check the transistors and the resistors in the collector circuit. good luck!
Posted on Feb 14, 2007
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I have a 36" Toshiba Tube TV that is about 9 years old now. Here is what seems to be the trouble. First the TV had a terrible blue tint for about two days and then fine blue lines in the picture. Now the blue has gone away completely and I have the choice of a picture that is too Red or Too green. No idea what to do. Don't really think it's worth repairing even though the picture is still sharp and clear.
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