In article ,
Puddin' Man wrote:

Panasonic 17" color tv, mnfgr'd 1987. Standard design, layout near as
I can tell.

Dog bumps tv stand, pic is still viewable, but goes snowy and has
pulsing waves across screen.

If I fiddle the power cord where it enters the box or bang on side of
box I can get the proper pic back, if only for a second or 2.

I'm not particularly skilled at electronics, but if I could get proper
access to where the cord connects to the power supply, I could likely
solder the connection or some-such. Access looks kinda problematical:
it's right under the nasty ol' CRT. The one that stores (what?) 20k
volts?

snip

Any ideas on how to approach it? Just workbench it and start
disassembling stuff? Cautions other than about the 20kv "gun" at the
back of the CRT? Etc, etc.

You're likely right to suspect a poor connection somewhere, possibly a
soldered joint that's cracked or similar.

It's almost certainly not the power cord connection, though, simply
because a poor connection there would generally cause the set to
intermittently turn itself off or not turn on, rather than cause snow.
Snow suggests something is amiss in the RF or perhaps video circuitry.

The first place I'd look is the RF or video input connection (on the
outside of the TV)--perhaps the connection is loose or corroded, or the
cable is breaking near the connector.

If that's not it, then it's some internal connection or solder joint in
the set. Positively do some research and reading up on how to safely
work around in a TV before thinking about opening it up. Besides the
high voltage for the CRT, there's high voltages in the power supply
circuitry and the danger of implosion. If you have any doubts, you'd
probably be better off taking it to a repair shop, assuming the set is
otherwise worth spending money on (i.e. the picture, when the set is
working properly, is bright and sharp and clear and generally well
behaved).

--
Andrew Erickson

"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot