Flat Screen Computer Monitor Repair Question

I was given a power supply board for a computer monitor to repair. I hooked up flourescent light strip to it and tied the on/off pin to + 5.25 volts from the board itself. I wanted to see if the light would illuminate. It did but only for a couple of seconds, then it turns off. The +5.25V supply goes to 5.37 while illuminated then back down to 5.25 after lamp goes off. I have tested the transformers with blue ring tester and the test ok. I also put an ESR meter on all the electrolytic caps and they appear to be ok. Any ideas?

Thanks