I have a Furuno 1700 radar displayng strange symptoms.
The display is not complete in terms of a full circle. Always a small
sector of the display is missing. Somtimes it is a 90 degree sector
missing and other time two small sectors of say 15 degrees are
missing.Changing the range causes different sectors to be ommitted.
After beng powered up for some time with the scanner rotating and in
standby mode pushing transmit causes a brief display of several
seconds followed by a power down presumably because somethng is taking
excessve current.
Any help or advce gratefully recd.
Tony

In the "old" days, a synchro motor followed the rotation of the antenna and
turned the yoke on the CRT so the beams stayed in sync. That was then, this
is now. There still has to be some form of rotary encoder up at the antenna
that sends a signal back down to the display so the display knows where the
antenna is pointing. I'd say there's something wrong at the antenna, like it
is binding, dirty, or the encoder is intermittent. The electronics might
sense problems like no rotation and shut the unit down before it ends up
baking someone on a mast three boats away.

There are certain things you, as an unlicensed person, can do to a radar
system, but playing with things that affect the frequency and power output
require an FCC license with a radar endorsement, and probably some
fancy/expensive test equipment. Taking the cover off the antenna drive
mechanism and cleaning it might be all it takes, but I'd guess there's more
going wrong, especially since you're missing segments of the display. That
points back to the encoder that follows the antenna. Either the gears are
slipping or the sensor itself is going bad.

Bob M.
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"Tony Dix" wrote in message
om...
I have a Furuno 1700 radar displayng strange symptoms.
The display is not complete in terms of a full circle. Always a small
sector of the display is missing. Somtimes it is a 90 degree sector
missing and other time two small sectors of say 15 degrees are
missing.Changing the range causes different sectors to be ommitted.
After beng powered up for some time with the scanner rotating and in
standby mode pushing transmit causes a brief display of several
seconds followed by a power down presumably because somethng is taking
excessve current.
Any help or advce gratefully recd.
Tony