This is one of the RCA clones with SCR Hoz sweep.
Later they did sell Zenith with the System 3 chassis.
Convergence is easy. TIP turn color off & brite & contrast about half way.
In other words dont drive it hard. If its just the top give the top
controls a little bump first to see if one has a bad spot. Also
watch for cold PC on the board, it gets hot there !
73 Zeno
LFOD !