How to backup/transfer Android Calendar for HTC Incredible running Android v. 2.3.4?

[AkronM]

I have Verizon HTC Incredible ADR6300. Running Android 2.3.4 -- the latest this phone will support. I rely on the Android calendar but cannot find a way to back it up. Google calendar will not import any events at all - nothing at all. I'm not even sure the calendar till transfer to a new Android phone. The problem has become real since I dropped the phone a few day ago. The digitizer/screen is fine but the LCD (AMOLED) is busted with no display at all. Going to try to transplant the motherboard to another ADR6300 I found on ebay with bad ESN. If ESN is on motherboard, I should be OK -- right? If it goes well, I have to find a way to backup my calendar so this doesn't happen again. Anybody know how I can do this and whether this calendar from v. 2.3.4 will transfer to new phone without having to manually reenter all past events, appointments, notes, etc.. I have a lot of income tax info on this calendar and can't afford to lose it. Appreciate any suggestions.