apc smarts 900 ups supply circuit is showing short

[ghulam_hussain]

Hi guys.
I am using ups apc smart900 for a long time but one day supply was gone ups giving backup correctly when electric supply came the supply lead burnout i again change its also burnout mean some problem in supply circuit.
So please can any one guys obtain schematcs of apc smart900 or advice to check by myself

 

[amanan]

the VDR is short in the main section

 

[santucj]

check rf3205 fet