IMHO the 9-160 gets a bad rap. Remember those sets had
the most complex Hoz/HV design ever. Having it on a
board was a blessing to the tech & customer. Under warranty
changing it was REQUIRED unless they were out of stock.
Out of warranty we fixed many for the common problems
but if it had a shorted HOT we changed the board. In home
almost all were changed. You cant work on one laying
on the floor in the dark with a little dog snapping at you !
Never had the piles of bad ones some had. Once in a while
a bad one but not that many. We kept 4 of each. Two in the
van & two in the shop. Replenishment was 3 times a week if
needed. Two distributors hand delivered back then & we
made a weekly trip to Zenith. Never out more than one day.
BTW sounds like you have an SM1971P. I had one, fantastic
set & sharp looking cabinet. Never liked plastic.
73 Zeno