SCT is way out of collimation how can I get it back into alignment?

My Meade 12 inch classic lx200 is so far out of collimation I cannot focus on anything.  my Zwo asi290mm mini  cannot reach focus. pictures from it are just blown out white.  no matter how I adjust the scope nothing can be seen (not even shadows).  How can I find a reference point between the focuser ,the corrector plate position and the secondary mirror position.  I am at an impasse.  Any ideas you may have are appreciated.  Tom Jackson

Page 52 & 53 of the owner's manual

https://www.ou.edu/lunarsooners/index/files/members/LX200_Classic_Manual.pdf

When I had a LX200 many, many years ago, I used a reflective round Christmas ornament placed in the sun and used that as a target if you can find one. Makes it very easy to see the diffraction rings and get it perfect.

great idea Ill give it a try when the clouds clear up , thanks tom jackson