Another Samsung plasma issue

[YamahaFreak]

This time I have a PN60F5500 (AF) that came to me with the following symptoms: TV goes through the motions of powering up, but there are no relay clicks or other noise, no power to the panel, and (as far as I can tell) no sound from the speakers. When you press the power button, the front standby LED flashes slowly several times, like it normally would while the set is powering up, then goes out, as it would once the panel comes up. The standby LED illuminates when the remote is pointed at the TV and buttons are pressed, so the TV is 'awake' enough to see the remote. You can power the set off and the power/standby LED comes back on, as it's supposed to when the TV is off. Inside the set, the green LED on the mainboard flashes at a rate of once every 4 or 5 seconds while the power is on. Various research has told me that the problem most likely lies somewhere on the Y-main (Y sustain) board, Samsung part number LJ41-10331A. I have replaced the small 7-pin IC after being told this could be the issue...this did not fix it. (I installed a socket, just in case.) Some threads online state that replacing three ceramic capacitors on the Y board inside the 64-inch version of this TV fixes the problems, but that size TV uses a different Y board than my 60-inch one, and I was unable to find any similar caps on my Y board. Everything inside my TV looks clean and tidy, no bulging caps or burned/smoked parts, blown fuses, etc. I'd love to repair, rather than replace, the Y board (if it's the culprit), since that is of course the most expensive board in the TV. I can of course answer questions and provide detailed photos, if they will help. I invested in a stand for this set already, so really hoping I can fix it!