JVC/NEC 42” plasma fault HELP PLEASE

[fredt]

Hi I have 2 jvc av42pd20es plasma TV’s which use a nec panel (NO. np42b2mf02 or 42nh-pdp-4).SET 1. The fault is when switched on you get a hiss sound and no picture. After trying a few times the screen lit up black with different color dots jumping around. I have tried testing fuses and voltages i.e. 170,60,5 and these appear to be correct. SET 2. The fault is when switched on you get a hiss sound and no picture. The Voltages seem correct. If anyone has any idea the help would be greatly received as I’m new to plasma repairs.
Gary