I have four Yn560IVs and have been really happy with them. Two have taken more bumps than other others, and now those aren't working. both seemed to have worked after any drops or bumps so its odd that they would just stop working after finishing their last shoot. They're receiving and even transmitting, and the flash zoom will respond to the commander , but they wont fire. Not in Manual, with the pilot, as a slave, etc. Yes, I changed the batteries. They're about a year and a half old so I can go with the extended warranty from my credit card but I'm wondering if anyone has opened them up to just change the bulb or whatever might be wrong with them.
Thanks.
