First your model is not in the Y-line catalogue. It is a drop in. The
high model number usually means its a high end set. BUT the
9-181-00 does not have a comb filter. Post a pix of the front & I can
match it to other models.
You can use any 9-181, 9-186 schematic to start, they are close enuf.
The retrace is probably the filter cap for the 200V that supplies the
3 video outs. Its a 5 or 10 mfd, replace with a 450V. Maybe its the whole
problem.
For subs you need to find someone with a CRSP or parts price list.
73 Zeno
LFOD !