Ruby Question popping noise

I have my ruby for 9 months and 500 hrs on blub. but now it seems when i start the unit i here it popping when trying to start. some times it will take 20-25 pops before bulb comes on. other times it's 3 pops. the room is air cond controlled and temp is about 65 degs . seems the colder it is the longer it takes. but sometimes it happens when it has been on for a couple of hours and i shut it down then come back in an hour and start it back up and room temp is up to 75 degs. I looked at some posts about this but nobody says if this is normal or not. they say it could be power supply/bulb etc. has anybody had the same thing. thanks for any info. the unit has been sent back for service once due to a fan issue ( with this issue unit would not come on but overheat light came on and fan ran at high speed at start up) since repair have not had this issue again any info would be appreciated

No your right it's more of a ping sound and that's what i was afraid of having to send it in again but thanks for the info and link.