I currently have my KV-27FS120 Sony TV connected to a cable box, which is receicing 100% signal. However, my television when powered on, the picture will tend to flash at times for a half a second and then reappear. I also recognized that the timer/standby light will flash 5 times. Is there any link between the two? Does my Trinitron tube need changing? Please advise. thx Bob

5 times flashing standby light is an error code that related with picture tube, basically it shows incorrect white balance (ik) problem. Your tv needs Screen volt adjustment and local tv repairman will fix it in minutes.
Let me know if you have electronics knowledge/ experience and interested to do it yourself.

Check whether the issue occurs with all the external devices like DVD Player, VCR, etc. If the issue is occurring with all the devices then the issue is with the TV.
Try these steps to check whether the issue is resolved.
1.Disconnect the power cable and connect it to a different working wall outlet.
2. Disconnect surge protector if you are using any.
3.Power reset the TV by turning it OFF for atleast one minute.
3. Reset the TV to the Factory defaults.
To reset the TV, turn it ON.
Press the RESET button on the Remote and press the POWER button on the TV at the same time. Now, TV will turn OFF and then back ON automatically.
Now, proceed with the Auto Program.
Check whether the issue is resolved after the Auto Program is finished.

All Sony TVs have a self-diagnose mechanism where the Standby light blinks to indicate that there is an internal malfunction in it.

Note: Your TV does not have the replacable LAMP.

If the issue persists TV requires service. Contact nearest Sony authorized repair center,