Just because the measurements out of circuit were different, doesn't necessarily mean the diode isn't the issue. What measurements did you get?
If the diode is not in fact the issue, I would have a good look around for anything that looks damaged. Check to make sure any fuses are intact (should get electrical continuity across them, or a resistance close to 0 ohms)
I did find [link|https://www.manualslib.com/manual/1251610/Philips-32pfl8605h-12.html#product-40PFL9705H/60|the service manual for this model|new_window=true]. It's very lengthy, but there is a ton of good information in it for fault finding.