White Balance Failure - Sony KD-34XBR970

[user181]

I have a Sony KD-34XBR970, which is a modern HD CRT set. A couple weeks ago while in use, the standby/timer LED began blinking a diagnostic test code. The code is 5 flashes of the LED, which the service manual states is "White Balance Failure." The set has continued to function with no observable degradation to the picture. The LED flashes the diagnostic code even when powered off, but unplugging the power cord resets this until the next time it is power on.

I have attached an excerpt from the service manual which defines the error code and lists probable causes. Does anyone have any experience with repairing this issue? Of the probable causes listed, is there one which has been the most common?

Do any of these repairs require extensive adjustments to complete? Since this set is such a complicated system, I'm trying to understand if there would be more effort involved than merely replacing ICs or swapping a board.

Lastly, given that the set is working right now, what is the typical progression of this fault?