Horizontal wobbling like that, in absence of sync input issues, suggests power supply or horizontal deflection issues.
So first thing to do is check your B+ voltage (I think for your chassis is at R301, big ceramic 220 ohm 15 watt resistor?).
Next, do an online search with your favourite engine for "k7000 chassis repair flowchart".
EDIT: I missed that you checked B+ above. Anyway, follow the flowchart and which suggests you check C57 and IC4.