De Vere 504 MkV Twin Lamp - Bulbs Not Working

I have a De Vere 504 MkV Twin Lamp enlarger and I've recently had a recurring issue with the bulbs not working. I've checked the voltage at the terminal block, just before the ceramic bulb connector and there's no power getting to the bulb connectors.

I had this issue a while back and weirdly it fixed itself after a few days. I've since tried different timers and that didn't make a difference. I only have the one power supply so unfortunately I can't swap that out.

Has anyone had the same issue? Or any ideas on how to fix the issue?

Solved. If there is an issue with just one bulb, the other bulb wont work, hence there was no voltage on the bulb wiring. And the issue was one of the ceramic connectors was a little loose. Gave it a wiggle and the old girl fired back into life. Happy days.