In article ,
"Sun Dragon" wrote:

I have a small Furuno radar where the echo return image is missing on the
left and right portion of the screen. The fore and aft images are fine.

I suspect the "brushes" or slip rings in the scanner unit are worn in the 2
o clock thru 4 o clock and the 8 o clock thru 10 o clock regions.
Am i correct in this assumption and if so, are kits available to renew the
contacts in the scanner?

Thanks,

Capt J. Vincent Collins
Master Oceans
F/V Sun Dragon



Depends on what model of Furuno display you have.... Most newer displays
have computer generated sweeps, and are Raster Displays. Should you
actually have a PPI with a real rotating Deflection Coil, do the
Range Rings, ALSO disappear along with the Targets? If Yes, then could
be the SlipRings, and or Brushes. If No, then it isn't the SlipRings
and or Brushes, as the Range Rings also have to go thru the same
connections as the target video. When you turn the "Gain" all the way
up, does the "Noise" also blank out in the same places as the Targets?
if Yes, then you have a Video problem. If No, then you have a receiver,
and or antenna problem. all the above is just basic Radar Repair
stuff....

Bruce in alaska an Old School Marine Radar Tech........
--
add a 2 before @

"Bruce in Alaska" wrote in message
...
In article ,
"Sun Dragon" wrote:

I have a small Furuno radar where the echo return image is missing on
the
left and right portion of the screen. The fore and aft images are fine.

I suspect the "brushes" or slip rings in the scanner unit are worn in
the 2
o clock thru 4 o clock and the 8 o clock thru 10 o clock regions.
Am i correct in this assumption and if so, are kits available to renew
the
contacts in the scanner?

Thanks,

Capt J. Vincent Collins
Master Oceans
F/V Sun Dragon



Depends on what model of Furuno display you have.... Most newer displays
have computer generated sweeps, and are Raster Displays. Should you
actually have a PPI with a real rotating Deflection Coil, do the
Range Rings, ALSO disappear along with the Targets? If Yes, then could
be the SlipRings, and or Brushes. If No, then it isn't the SlipRings
and or Brushes, as the Range Rings also have to go thru the same
connections as the target video. When you turn the "Gain" all the way
up, does the "Noise" also blank out in the same places as the Targets?
if Yes, then you have a Video problem. If No, then you have a receiver,
and or antenna problem. all the above is just basic Radar Repair
stuff....

Bruce in alaska an Old School Marine Radar Tech........
--
From Lynn, an even older marine radar tech (title under dispute)
I think the original poster suspected slip rings (and or brushes)
in the scanner unit. Unless there were some Furuno radars older than dirt
that had slip rings, none that I know of had slip rings up there. Furuno
seemed dedicated to fixed or stationary transceivers, shooting RF to and
from the antenna through a rotating or rotary wave guide coupler.
You are correct in that if the problem is in a display unit with
the "conventional"(?) rotating deflection coils, slip rings could easily be
the problem, as you pointed out.
The more recent (20 years?) Furuno's with raster scan displays
could have a video problem which would blank out 90 degree sections of the
video scan presentation at a time. The only one I ever saw with the port and
starboard quadrant targets (rings, snow and all) missing had a video
processor problem that could not be corrected (by me, anyway) without
replacing the board containing the video processor.
Heating and cooling around on that board, in the shop, running on a
simulator, would make the problem come and go. Seemed to be most sensitive
around a big ol' many legged surface mount chip not stocked at Furuno USA.
Board exchange fixed it quick enough, but not all that cheeeep.
Old Chief Lynn, 20 WPM Extra (and other wallpaper)

"Lynn Coffelt" wrote in
:

Seemed to be most sensitive
around a big ol' many legged surface mount chip not stocked at Furuno
USA. Board exchange fixed it quick enough, but not all that cheeeep.
Old Chief Lynn, 20 WPM Extra (and other wallpaper)


Come on, Chief! Haul out that big Weller that dims the lights when you
pull the trigger and unsolder those 80-wire ICs!...(c;

I took a Roland (keyboards and musical toys) tech certification course up
in Charlotte so I could get paid for doing warranty repairs on their
products. They were adamant at us troubleshooting these very dense
computer boards with surface mount technology down to the component
level. I asked, "Why? We're not going to replace anything that dense
out in the field...swap the boards and let Roland fix it." One of the
guys from NC wanted to go out in his truck and get HIS Weller so we could
swap out a few chips on the brand new expensive keyboards Roland was
showing off to the class. The Roland guy cringed and finally agreed
after the Good Ol' Boys showed their hands....(c;

ANY electronics, no matter how expensive, has become disposable after
about 4 years, some even less, now. The companies act as if a 5-year-old
electronic toy that cost $8000 never existed......corporate amnesia sets
in.

Larry
--
Democracy is when two wolves and a sheep vote on who's for dinner.
Liberty is when the sheep has his own gun.

"Larry" wrote

Come on, Chief! Haul out that big Weller that dims the lights when you
pull the trigger and unsolder those 80-wire ICs!...(c;

Geeze, Larry, now, as Bruce sometimes says, "I feel a story coming on".

Mike and I were in the pilot house of the Washington State Ferry "M/V
Vashon, performing
delicate surgery in the belly of a Furuno radar display. Transistor on a PCB
needed replacement.
I grabbed my trusty Weller D550 and Mike took the extension cord and
searched for an outlet.
He asked the Mate if he knew where there was 120 volts. Mate asked if 110
volts would do, there was an outlet
right behind that bench. Sure! Pulled the trigger on the Weller and nothing
happened. Just a little curl of smoke
from the gun's ventilation slots. Let go of the trigger and smoke, flames
and sparks came shooting out of all
the gun's vent slots. I threw the Weller gun on the pilot house deck and
started stomping on the fireworks display.
Mike looked terrified. I WAS terrified. Mate calmly pulled the extension
cord plug out of the wall socket.
Mike noticed then that the outlet on the bulkhead was labeled "110 Volts
DC". Sheesh. Be glad rocket science is
not our profession.

Old Chief Lynn (Larry, I touched a Roland once!)

In article ,
"Lynn Coffelt" wrote:

"Larry" wrote

Come on, Chief! Haul out that big Weller that dims the lights when you
pull the trigger and unsolder those 80-wire ICs!...(c;

Geeze, Larry, now, as Bruce sometimes says, "I feel a story coming on".

Mike and I were in the pilot house of the Washington State Ferry "M/V
Vashon, performing
delicate surgery in the belly of a Furuno radar display. Transistor on a PCB
needed replacement.
I grabbed my trusty Weller D550 and Mike took the extension cord and
searched for an outlet.
He asked the Mate if he knew where there was 120 volts. Mate asked if 110
volts would do, there was an outlet
right behind that bench. Sure! Pulled the trigger on the Weller and nothing
happened. Just a little curl of smoke
from the gun's ventilation slots. Let go of the trigger and smoke, flames
and sparks came shooting out of all
the gun's vent slots. I threw the Weller gun on the pilot house deck and
started stomping on the fireworks display.
Mike looked terrified. I WAS terrified. Mate calmly pulled the extension
cord plug out of the wall socket.
Mike noticed then that the outlet on the bulkhead was labeled "110 Volts
DC". Sheesh. Be glad rocket science is
not our profession.

Old Chief Lynn (Larry, I touched a Roland once!)




That's why I always carried a Weller Pencil Rsistance Heated Woodburner
in my Toolbox. didn't matter if it was AC or DC, as long as it was over
90V.

Bruce in alaska worked on to may converted WWII 110DC ships......
in my younger years.....
--
add a 2 before @

"Lynn Coffelt" wrote in
:

Mike noticed then that the outlet on the bulkhead was labeled "110
Volts
DC". Sheesh. Be glad rocket science is
not our profession.



Great story, Thanks! I was in NYC, back in the early 80's working on the
field change 10 and 14 of the main HF transmitters at the CG Electronics
School on Grosvenor's Island for a month. CG and Navy hired us (Tracor)
to do this critical field change to a big engineering screwup. The
multikilovolt DC from the PS to the main amp's pair of big ceramic
tetrodes used to explode the connectors and blow the main case cabling.
Some idiots also forgot to INTERLOCK the 3-phase, 400 Hz, 440VAC to shut
off the lethal AC line when sailors opened the cabinet. Some died.
440VAC will wake you up, temporarily. Sailors had installed these
changes, sloppily, and more died when the guide pins shoved the 440VAC
sloppy wiring into the guide pin socket. The explosions looked
impressive, but I digress, as usual.....(c;

We lived in a flophouse hotel on 8th Ave near 42nd St that dated back
into the 1930's, I'm sure. ($130/day) The building had 110VDC outlets in
every room with warning signs on them that it was DC and do NOT plug AC
appliances in, here. DC was required, still, because the old elevators
were all DC operated....

Well, my assistant technician knocked on my room and was REALLY ****ed
off. He'd plugged his BRAND NEW portable color TV he'd bought off Times
Square into the DC outlet and got a similar fire as you did! It was
TOAST...(c;

Larry
--
Democracy is when two wolves and a sheep vote on who's for dinner.
Liberty is when the sheep has his own gun.

Bruce in Alaska wrote in news:bruceg-
:

Bruce in alaska worked on to may converted WWII 110DC ships......
in my younger years.....


USS Everglades (AD-24) circa 1952 had 110VDC motor-generators in Radio II
on the TBK and TBL WW2-vintage LF/MF/HF transmitters. The DC genny was a
separate steam turbine-driven big old generator in the main engine room
running off the same steam as the main turbines. Our deck gear was all
DC motor powered, even the cranes. The control panel was a huge black
Bakelite panel with knife switches and huge fuse holders, all exposed to
anyone leaning over the wooden bar that was chest high to keep you from
falling into it in rough seas. It was like looking into the engine room
of an old 1930 movie.

If I keyed up all 4 TBKs and TBLs at full power, the big motors would
just max out the throttle on the steam generator, slowing the ship with
reduced steam pressure by about 2 knots as she had manual throttle
controls in the engine room. Radio II was 3 decks above the engine room
and I could hear the DC generator whine from the heavy load current
causing magnetic field distortion in the core...

They nearly killed me in Radio II's M-G compartment. I was comparing the
winding resistances in a good HVDC generator (3000VDC) to one that was
sick, trying to figure out what was wrong with it. The switches in Radio
Central were all tagged out properly and the logs signed, as required.
An RM3 ignored my tags and started the good 3000VDC generator my hands
were in. I woke up in Sick Bay, a couple hours later, to the face of a
very worried 4-stripe Navy Captain, my CO. I was still shaking quite a
bit but confirmed to my CO that I had found the problem in the deficient
genset and would have it fixed as soon as I could stand up and go back to
work. That took a couple of weeks as he ordered me off the ship for 2
weeks free leave as soon as the doc cleared it, telling me he didn't want
to see me anywhere near the ship for 2 weeks.

DC power systems on ships were quite neat, indeed. My calibration lab
was powered (at sea) by a GM 6-71 DC genset into a black bakelite control
board that used to power the after 5"-38 gunmount, until they installed
the DASH helo flight deck in its place. 110VDC from our own generator
powered a DC to AC M-G set off its output, providing me with 25KVA of 3-
phase 408VAC to the cal lab's tube-powered voltage stabilizers on each
phase. In the Med, where the TVs use 50Hz instead of 60Hz, I used to
turn down the M-G set's speed to 1500 RPM and increase the field current
to bring back the 408VAC, running the whole lab on 50Hz so our TV picture
wouldn't "modulate" with the 10 Hz difference waves. The Chief
Electrician's words to me were, "If you burn that damned thing up doing
this, YOU are going to be the one rewinding it, not US! (referring to the
Electrical gang)...(c; It ran fine as our load was never over about 6KW,
tops. The Cal Lab had incandescent lighting running directly off the DC
panel, which eliminated a lot of the AC hum in the air inside the lab.
The electricians would screw up main AC power in the ship, putting the
whole ship in the dark....except for that "Beacon In The Night" coming
out of the cal lab's X hatch...(c;

AC power was missing as Everglades approached Charleston in 1968. All
the receivers on the ship were ship AC powered, so we had no comms. ET1
Butler, WB4THE/MM2 at the time, had his ham radio station in the
separately-powered cal lab running...er, ah...1000 watts from his quad of
813 tubes in a homebrew amp Navy supply provided, but didn't know it. My
captain asked me if I could contact Cliff K4OKD, and get us a phone patch
to the base ops at the Navy base. Another ham I found got Cliff on the
phone and Cliff hurried home to provide the patch. At first, confused by
the phone call from a ship at sea, base ops refused to believe it was us.
But, the comm officer ashore recognized us and they sent out the pilot
and tugs to get us to the dock. My ham radio station aboard Everglades
was quite secure, both from running phone patches for my captain to his
wife, and from this one incident where my Heathkit HW-101 transceiver and
homebrew linear was the only comms on the ship!

Larry
--
Democracy is when two wolves and a sheep vote on who's for dinner.
Liberty is when the sheep has his own gun.

Great stories Larry and Bruce,

Just for reference. Many of the merchant fleet were DC until the advent
of variable frequency drives for AC motors (late 70's?). Until then
there were few ways to control and AC motor and the winches and lots of
my engine room equipment needed to be speed controlled.

Some NYC subway line was still DC when I wrote my first license in 1971
and yes some places were still feeding from that for elevator drives
even then.

Matt Colie

Larry wrote:
Bruce in Alaska wrote in news:bruceg-
:


Bruce in alaska worked on to may converted WWII 110DC ships......
in my younger years.....



USS Everglades (AD-24) circa 1952 had 110VDC motor-generators in Radio II
on the TBK and TBL WW2-vintage LF/MF/HF transmitters. The DC genny was a
separate steam turbine-driven big old generator in the main engine room
running off the same steam as the main turbines. Our deck gear was all
DC motor powered, even the cranes. The control panel was a huge black
Bakelite panel with knife switches and huge fuse holders, all exposed to
anyone leaning over the wooden bar that was chest high to keep you from
falling into it in rough seas. It was like looking into the engine room
of an old 1930 movie.

If I keyed up all 4 TBKs and TBLs at full power, the big motors would
just max out the throttle on the steam generator, slowing the ship with
reduced steam pressure by about 2 knots as she had manual throttle
controls in the engine room. Radio II was 3 decks above the engine room
and I could hear the DC generator whine from the heavy load current
causing magnetic field distortion in the core...

They nearly killed me in Radio II's M-G compartment. I was comparing the
winding resistances in a good HVDC generator (3000VDC) to one that was
sick, trying to figure out what was wrong with it. The switches in Radio
Central were all tagged out properly and the logs signed, as required.
An RM3 ignored my tags and started the good 3000VDC generator my hands
were in. I woke up in Sick Bay, a couple hours later, to the face of a
very worried 4-stripe Navy Captain, my CO. I was still shaking quite a
bit but confirmed to my CO that I had found the problem in the deficient
genset and would have it fixed as soon as I could stand up and go back to
work. That took a couple of weeks as he ordered me off the ship for 2
weeks free leave as soon as the doc cleared it, telling me he didn't want
to see me anywhere near the ship for 2 weeks.

DC power systems on ships were quite neat, indeed. My calibration lab
was powered (at sea) by a GM 6-71 DC genset into a black bakelite control
board that used to power the after 5"-38 gunmount, until they installed
the DASH helo flight deck in its place. 110VDC from our own generator
powered a DC to AC M-G set off its output, providing me with 25KVA of 3-
phase 408VAC to the cal lab's tube-powered voltage stabilizers on each
phase. In the Med, where the TVs use 50Hz instead of 60Hz, I used to
turn down the M-G set's speed to 1500 RPM and increase the field current
to bring back the 408VAC, running the whole lab on 50Hz so our TV picture
wouldn't "modulate" with the 10 Hz difference waves. The Chief
Electrician's words to me were, "If you burn that damned thing up doing
this, YOU are going to be the one rewinding it, not US! (referring to the
Electrical gang)...(c; It ran fine as our load was never over about 6KW,
tops. The Cal Lab had incandescent lighting running directly off the DC
panel, which eliminated a lot of the AC hum in the air inside the lab.
The electricians would screw up main AC power in the ship, putting the
whole ship in the dark....except for that "Beacon In The Night" coming
out of the cal lab's X hatch...(c;

AC power was missing as Everglades approached Charleston in 1968. All
the receivers on the ship were ship AC powered, so we had no comms. ET1
Butler, WB4THE/MM2 at the time, had his ham radio station in the
separately-powered cal lab running...er, ah...1000 watts from his quad of
813 tubes in a homebrew amp Navy supply provided, but didn't know it. My
captain asked me if I could contact Cliff K4OKD, and get us a phone patch
to the base ops at the Navy base. Another ham I found got Cliff on the
phone and Cliff hurried home to provide the patch. At first, confused by
the phone call from a ship at sea, base ops refused to believe it was us.
But, the comm officer ashore recognized us and they sent out the pilot
and tugs to get us to the dock. My ham radio station aboard Everglades
was quite secure, both from running phone patches for my captain to his
wife, and from this one incident where my Heathkit HW-101 transceiver and
homebrew linear was the only comms on the ship!

Larry

--
target of diversity
victim of affirmative action
refugee from the war on poverty
minimized by political correctness

Thanks for the replies, I took the scanner unit apart and found the problem
to be the waveguide coupling bearing was siezed up. Because the waveguide is
rectangular in shape and oriented with the long dimension fore and aft
produced the target display problem of not seeing targets port and stbd!

thanks again.


"Sun Dragon" wrote in message
...
I have a small Furuno radar where the echo return image is missing on the
left and right portion of the screen. The fore and aft images are fine.

I suspect the "brushes" or slip rings in the scanner unit are worn in the
2 o clock thru 4 o clock and the 8 o clock thru 10 o clock regions.
Am i correct in this assumption and if so, are kits available to renew the
contacts in the scanner?

Thanks,

Capt J. Vincent Collins
Master Oceans
F/V Sun Dragon

Oh, for gosh sakes, I thought as an "Old Timer", I'd seen or heard of
everything!
I've never seen that bearing froze up!
Thanks for reporting back.

Old Chief Lynn


"Sun Dragon" wrote in message
...
Thanks for the replies, I took the scanner unit apart and found the
problem
to be the waveguide coupling bearing was siezed up. Because the waveguide
is
rectangular in shape and oriented with the long dimension fore and aft
produced the target display problem of not seeing targets port and stbd!

thanks again.


"Sun Dragon" wrote in message
...
I have a small Furuno radar where the echo return image is missing on the
left and right portion of the screen. The fore and aft images are fine.

I suspect the "brushes" or slip rings in the scanner unit are worn in
the
2 o clock thru 4 o clock and the 8 o clock thru 10 o clock regions.
Am i correct in this assumption and if so, are kits available to renew
the
contacts in the scanner?

Thanks,

Capt J. Vincent Collins
Master Oceans
F/V Sun Dragon