Bulb replacement will only repair reduced brightness or contrast problem. Sometimes shadows or lines (usually curved or circular) appear in the image if the bulb is weak or faulty. This will show with the color turned off and a black and white image displayed.
Most visible color faults are caused by optical engine failure. Big cost, as the complete assembly has to be replaced.
Occasionally there are video processing or tuner problems that require serious troubleshooting to determine what board has to be replaced.
If the fault is not visible on the customer menu and appears only with input signal viewed, you may have a cable box or other signal input problem. Check various input signals to see if the problem is visible with all inputs.
Running the channel scan with vhf input signals sometimes clears up a lot of problems. Your cable company may have changed or adjusted rf modulators or other equipment and the tv needs to be aligned to the changed signal. Auto tuner scans will take care of these problems. easyab