CRT TV vert section

Question

In one 21"color CRT tv vertical linearity is lost suddenly and picture is streched from upper side and compressed from bottom side (no rolling and we can see the movie but streched.In vertical section preset could not change the error.Vertical IC 7830.I replaced 1000Uf and 220 UF capacitors with new one but didnt solve.(i donthave oscilloscope )what can i do now.Thanks in advance