LG 42pc1dv picture gone

[oggy]

Hi. Picture gone on an LG 42pc1dv-ec plasma. Sound OK, inputs OK.
Vs fuse blown on y-sus board. Replaced it but still no pic.

Checked voltages from PSU when switched on from cold.
Vs>300v Va>80v. Label says they should be Vs=185 and Va=60.
Noticed voltages slowly dropped to about their correct levels after 20 mins.
Is this normal as the set warms up ?

Read that the y-sus can give problems on these models.
The replaced fuse has not blown again so now I am confused (no pun intended)!
Only a novice so any help appreciated. Thanks.