A great copy of the manual, and the only one I could find anywhere on the net! The circuit diagrams are easily readable, all component values marked and easy to see. A highly appreciated download!
The TEAC A-1500's Service Manual was instrumental in reviving this classic reel-to-reel. Not only does it have the schematics, exploded parts diagram and parts list, it also provided mechanical adjustment information that approximate factory default settings.
Text excerpt from page 20 (click to view)
5) Drive circuit The STR-S5707 applies the proportional drive system in order to minimize turn-on and saturation loss, and storage time. In the conventional RCC system, turn-on loss and switching noise due to the surge current appearing when the power transistor turns on are high as because the transistor is driven by the drive current shown in FIg. 10-1. In addition, since is decreases linearly when the transistor turn off and a peak value of lB2 is not large, the storage time is long and the VCE(SAT) voltage is high, which results in large turn-off loss. The circuit and the waveforms of the proportional drive system which is applied to the STR-S5707 in order to reduce these switching loss and shorten the storage time are shown in Fig. 10-2 respectively.