Cloth covered wiring is fine. I try not to replace things unless there will
be an improvement. Power cords can be unsafe, but the cloth usually does
not deteriorate.

Once caution about using an S-38 in the basement. Remember the chassis is
ac-dc and there can be some conduction through the floor. More than one
amateur has been killed working in a basement, when insulation failed. One
of the league's heavy hitters was killed in the 30's when his ac transformer
shorted out to a chassis and he became the path to ground.

A GFI would be a good investment in a basement when working with the old
gear.

Colin K7FM