I've got the classic single horz. line, (problem goes on and off). I understand that the issue is in the Vertical IC and possibly a bad cap or dry joint, etc. in that same vertical neighborhood.

Here the interesting thing - It works fine for a while, but will suddenly flicker and if you give the tv a good whack it will clear up. Or if it is "fine" and you whack it (to provoke the problem - it will flicker and sometimes completely collapse - until you bang a few more times).

Does this seem to favor a dry joint over anything else? Or could a dry / old cap or bad vert ic respond like this after jarring it?

Thanks,

David

yes it's a bad solder connection solder all the pins on the vert ic
doc

Agree with doc as far as it goes. If you are hitting the thing to get it to work, that will end soon, then you need a new IC, a feed resistor and perhaps a diode.

So instead of resoldering the pins - you'd recommend just purchasing a new veritcal IC and swap it out now? If there is a diode issue, could that damage the new IC?

Thanks,
David

I would suggest to resolder all vertical and horizontal components and connections.

One favours soldering around the neighbourhood of the vertical IC, check the yoke plug and test for voltage to the vertical IC.