These sets had a screwy way of labeling parts. Ex. TP15 means
" Transistor Power supply #15" Every stage has a designation.
Most sets used numbers like Q801. The 800 series numbers were power supply.
IIRC TP15 was the on/off for the set. Hows about a pix of the chassis ?
Also if you have a schematic post that.
73 Zeno
LFOD !