Need help! compatibility among combos?

my combo (qsi sbw 241) is out of repair now. i can not find a new one in the market.

i would like to know if there is any identical combo (any brand, any model) which is 100% compatible to my combo.

i write to this forum because i was told that thas was a highly technical issue and there was a high risk of a wrong replacement.

anybody to help?

thank you.
hasim