First of all I want to thanks again Yustas for the informations I find in minilablaser.com/fujifilm-troubleshooting section regarding laser errors and symptoms....
I succeed to solve my problem folowing this steps :
1- after swapping the RED AOM with GREEN AOM , I find both in working state - so the problem was in optical block (red laser - optical surfaces - AOM RED crystal or electrical connections)
2- disassembly the laser box and box covers to have acces inside
3- visual evaluation of interior and optical surfaces (lenses-mirrors)
4- surprisingly I find lot of dust especially on the small rectangular mirror coresponding to SOS optical sensor, but also on all internal surfaces of assembly
5- carefully clean everithing I can triyng to remove dust everywhere I can, with special attention to SOS signal reflecting mirror and the path of Red laser
6- Contact spray applied on all laser assembly conectors
And to my delight the Frontier work again like new.
Hope my story will help someone in similar situation