From 1992 - 1997.I was a Tech for a consumer electronic company.There were 3 mini department.There's the TV dept.(Television repairs).There's Video dept.(VHS,Camcorder repairs) and Audio dept. where I was in repairing mini hifi,cd players,anything that emits sound without visual gets through here.Though I don't repair TV and Video stuff I tend to occasionally became a fly on their wall.
Long story short most of the Takamine Preamp failure was due to leakage of all the electrolytic caps.Make sure you use a very tiny and sharp soldering tip to remove those caps.If you were to buy the same type of caps,make sure you buy more of it.Use or unused your preamp will cease and the caps will leak again in a year or two.Trust me.
My Thanks to Hugo Vilela from Portugal for the pictures above.