Technical documentation of some transcievers from YAESU:

FT-817 service manual is here  (20MB)

FT-847 service manual is here (5MB) and here (15MB)

FT-847 user manual, schematics are here (9MB)

FT-847 block diagram in higher quality is here (1MB)

More information about FT847 are here

FT-857 service manual is here (13MB)

FT-897 serivce manual is here (12MB)

FT-1000MP Mark V. service manual is zde (120MB)

Discussion about technical matters such transcievers can be lead here

Technical doumentation of some other transcievers:

Snezka TRX210 - diagrams and documentations are here

BMT226 - Allamat 88 - diagrams and documentations are zde

R2CW - diagrams and documentations are zde (3,8MB)