Sony KDL-32S5500 Backlight issue

[Turnip]

Hi folks,
Have one in where with inverter SSI320-8C01  Lamp on and Lamp detector are both around 3.5v and I get a brief rather dim flash then inverter cuts.

Suspect maybe old cold tubes as 24v supply is OK. Drive chip is an 0Z9972ASN  but I can find no pinning info. Wonder if there's a pin I can bias to keep it running ? - Thanks - Chris.