That last explanation most closely resembles what is happenning and I would
say that is probably the problem except for one thing. This problem was
also occurring while I was night fishing and I wasn't in the land of the
midnight sun either. :-)

I'm curious about one more thing that you might have an answer for. With
the transducer submerged in a 5 gallon bucket of water, when I turned on the
unit, I can hear a clicking sound coming from the transducer. The frequency
in which it clicks is in sync with the movement of the display from right to
left. When I first turn it on, the clicks occur at roughly 2 times per
second and then suddenly changes to a guesstimate of 40 times per second
sounding a lot like a cricket. When it is clicking at 2 times per second
the screen seems to look okay but the intermittent vertical black line and
the erratic display seems to happen when it starts clicking at the 40 times
per second. The unit operates at 200/50 kHz so I know I'm not hearing the
sound of either of those frequencies as they are well above the audible
level of all living animals with the possible exception of bats. My
question is, should the transducer be making an audible clicking noise at
all? Could there be an arc going on inside the transducer as that is what
it sounds like?

I'm really dissapointed with Raytheon as I already sent it back once and had
to pay for the repair. It's now acting up the same way again and I know
they won't replace it because they've already refused to the first time and
insisted on a repair only. I just ordered a Garmin 250C Fishfinder but
would like to salvage and sell this one if possible or scrap it if it isn't.

Jerry


"Larry" wrote in message
...
"Jerry" wrote in
:

Thanks Larry for the very informative feedback but the problem goes
further than that and maybe I didn't explain myself clearly enough.
If I'm watching the screen scrolling by with fish or not, all of a
sudden the display ends with a dark vertical black line and just a
clear empty screen following it. I can stay clear for a 1/4" width or
a 1" width up to a full screen width before I see another dark
vertical line followed by the normal display of the bottom and fish if
there are any. It has gotten so bad that I'm now getting a 1/2" of
display, a vertical line followed by a 1/2" of blank screen, a
vertical line, then another 1/2" of display, then a vertical line
followed by a 1/2" of blank screen, a vertical line, and this may go
on repeatedly forever. Sometimes if I shut it off and wait awhile it
may work okay for a minute or so and then it starts to act up again.


Another thought came to mind. The display is stored in a memory IC for
the display. It is being written in order from top to bottom along the
right side of the display as you look at it, then on each time the
display moves, those little jerks they all do, that line and all the
lines before it are jogged one line to the left, making room for the next
line. If that memory chip, or the driver to it, is overheating, it will
also make a moving blank or black vertical section for as long as it's
blanked out.

Tell the factory to HEAT this unit up when you send it back to them.
They'll have a heat box to try to create the overheat condition I think
you have. They may simply choose to replace the whole unit, rather than
attempt a repair at all, saving the company more money in technician
labor costs than the unit costs them to buy from China or wherever the
slaves make them. Garmin, Eagle and the others do it all the time on
difficult, intermittent problems.



--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.