This is an old FM mobile unit but has 25W. Does anyone have the -service- manual or schematic? I already found the owners manual (no schematic).
I like tinkering with this old simpler stuff; as it has power adjustments via pots therefore presumably voltage, some AM experiment may be possible with the transmitter.
Icom never issued a service manual for the IC-255A. The schematic and board layouts are separate sheets that come with the operating manual. People who scan stuff probably never read the Table of Contents to see what comprises the complete manual.