The red/yellow striped wire ought to be the center tap of the high voltage winding, and as such I guess it should go to ground.
The black wires with stripes are probably different voltage taps for the primary.
There was an American standard for the colour codes:
(from the MEF's own archives )This ties back to the Radio Manufacturers of America (RMA) and that organizations follow on groups of RETMA and EIA and the milspec from Mil-T 27 Rev. E. Copyright? I'll transcribe it and give attribution to source. The RMA/RETMA/EIA coding was sourced from Audio Cyclopedia by Tremaine (Howard W. Sams publisher) and the MilSpec from Mil-T 27 Rev. E published by the USofA Government.
Power Transformer color codes (RMA/RETMA/EIA)
Untapped primary: Black – Black
Tapped primary: Blk – Blk/Yel – Blk/Red
Sec. HV: Red – Red/Yel – Red
Sec. Rect. Fil.: Yel – Blu/Yel – Yel
Sec. Fil. 1: Grn – Grn/Yel – Grn
Sec. Fil. 2: Brn – Brn/Yel – Brn
Sec. Fil. 3: Slate – Slate/Yel – Slate