Thanks for replying Keith, and sorry for delay in responding. I have checked supply lines and all seems ok. I have some more information that may help in indentifying the circuit. The mainboard is PLV9121E13 and the eeprom is 24C04A, tuner DT58WT-2B-E (or TCL0031390). The supply to the eeprom is 3.27volts so this may be the problem but cannot chase the circuit through to see where it is coming from. The main 5v regulator is giving 5v ok so i guess the supply to the eeprom may be switched when the set comes out of standby.