Goodmans ld3261hdfvt standby light flashing?

I have a goodmans ld3261hdfvt that when you turn it on it starts up on dtv then goes to standby and flashes blue red 13 times. Not able to get tv up even to an av port. I know it's a protection facility but what do I need to replace to get tv back up and running again. I'm a tv engineer but cannot get service manual anywhere. Comet refer me to call engineer out but I refuse to pay hefty call out charges for what appears to be a common fault with these sets....

Any assistance gratefully accepted