My samung spn4235 powers up, I have sound but no

Sounds like the inverter board for the lights is dead. You can verify this by taking a flashlight and shining it on the screen up close while its running to see if you see picture. If you do then the inverter board is dead. Rare occasions will the inverter board be fine, but the bulbs die.
If you don't see a picture then your power supply might have a problem with the rails supplying the video and light.