Hola de nuevo.
Prueba esto:
Código PHP:
if(form.OBSCTA.checked == false) {
form.R1[0].checked = false;
form.R1[0].disabled = true;
form.R1[1].checked = false;
form.R1[1].disabled = true;
form.R1[2].checked = false;
form.R1[2].disabled = true;
form.D1.selectedIndex = 0;
form.D1.disabled = true;
form.T1.value = '';
form.T1.disabled = true;
} else {
Espero que te sirva. Saludos,
