I
bought this small TV from a Radio Shack back in my college days (1990s)
and recently (April 2020) powered it back on as I needed a portable
video monitor. I found that the audio worked ok, but there was
dim picture. Just a dim green haze.
I opened the unit
up and upon close inspection saw a stain on the power supply board
(connects to the batteries). I found a corroded 330uF 6.3V
electrolytic on the other side, marked C116. This was replaced
(large orange capacitor in image below) and the board was cleaned.
There was a corroded SMT transistor on the other side, and I was
not optimistic about it working.

Inside of the Pocketvision. The orange capacitor was replaced. I documented my work
with a silver Sharpie pen.

A test shows that the TV worked once again.

The A/V cable was a special order. The resistor is 46KOhm.
One
accessory I bought along with the TV was the A/V cable. The end
that plugs into the TV is a regular 'stereo' mini-jack. As you
can see above, the 'tip' is the Audio, the 'ring' is the Video, and the
'sleeve' is the reference return.
There is also an external
antenna connector. Not very useful these days, but I decided to
investigate that one as well. This is also the same type of
mini-plug as used above, but the 'ring' is the antenna (through a few
pF blocking capacitor in the TV), and both the 'sleeve' and 'tip' are
reference return.
Finally, there is a power input jack as
well, which I did not investigated. You can see it in the bottom
right in the first image above. I did notice a diode in series
with this input jack, so that is good protection. The connector
looked like a small barrel type. As an additional power note, I
tried using four fully charged NiMH batteries (about 1.3V each) and the
unit did not power up.
Value of this small TV at the time of
this writing is very low, about $30 on Ebay. However, I am happy
I did not junk this item and I may use this as a small monitor again.