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Furuno Radar Problem

Discussion in 'Boat Electronics' started by Bruce in Alaska, Jan 22, 2007.

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  1. 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

    Bruce in alaska an Old School Marine Radar Tech........
  2. Lynn Coffelt

    Lynn Coffelt Guest

    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)
  3. Larry

    Larry Guest

    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

  4. Lynn Coffelt

    Lynn Coffelt Guest

    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!)
  5. 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

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

    Larry Guest

    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 pissed
    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

  7. Larry

    Larry Guest

    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, 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!

  8. Matt Colie

    Matt Colie Guest

    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
  9. Sun Dragon

    Sun Dragon Guest

    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.
  10. Lynn Coffelt

    Lynn Coffelt Guest

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

    Old Chief Lynn
  11. That really makes no sense Lynn. If the Bearing was froze, the antenna
    wouldn't Rotate, and it wuld be evident externally. Now if the Rotory
    Joint was froze, the Alignment Keeper on the top of the T/R Pan, would
    have to be missing, or broken to allow for the miss-alignment of the two
    Flanges. It should only give a very narrow widow of passable RF. Just
    a couple of degrees, plus or minus, at each correct alignment.

    If the later, is the case, then I am with you, very strange occurance,

    Bruce in alaska that would be one for the Books.......
  12. Lynn Coffelt

    Lynn Coffelt Guest

    Yup, once in a while the scanner bearing seal or water in the motor
    housing would let the scanner main bearing get corroded or filled with gunky
    stuff, but never saw the rotating joint freeze up!
    I have, a couple of times, managed to successfully break, bend or
    otherwise defeat the waveguide alignment scheme. Targets were not all that
    lively, and wiped out the crystals in fairly short order. Probably didn't do
    the maggie too much good either. Head hanging in shame. Again.

    Old Chief Lynn
  13. No shame required, I amagine that it just wasn't totally thought thru...
    and I actually went over and looked it up in the Service Manual.....

    Bruce in alaska
  14. Lynn Coffelt

    Lynn Coffelt Guest

    ..> > Yup, once in a while the scanner bearing seal or water in the
    Good grief, is that something made from aunts or cousins?..........

  15. Larry

    Larry Guest

    Our SPS-6 aboard USS Everglades (AD-24 may she rest in peace) ran on a
    pair of Fallopian tubes. Every new ET aboard was sent down to After GSK
    with a supply chit in his hands for a new pair for the radar as soon as
    possible, to welcome him aboard.

    The supply guys in After GSK were in on it. They'd act non-interested
    and take the paperwork, stamping it properly, then go in the back and cut
    off two 6" lengths of rubber surgical hose specially planted for the
    newbie ETs. Of course, they'd make him SIGN for the new tubes before
    leaving so we could publish proof of his stupidity in the ship's next

    There were two fittings on the SPS-6 antenna mount and one on the
    Raytheon Pathfinder's mount that required relative bearing grease. It
    came in a green government tube marked "Jelly, Petroleum" from Forward
    GSK, a different series of ladders into the bilge level storeroom in the

    Between the bogus supply runs and the mail bouy watch on the bullnose,
    after a couple of weeks, it was real hard, for some reason, to get young,
    green technicians to make any real supply runs....Until that time, it was
    great fun!

    Larry ET1
    Supervisor - Shop 67B - Metrology Laboratory
    USS Everglades (AD-24) '66-'69
    Cruisin' the Med for Uncle Sam
  16. Sun Dragon

    Sun Dragon Guest

    A roll of aluminum foil and a "green" deckhand made for good humor, I would
    instruct the deckhand to wrap himself in foil, stand upon the foredeck, as
    we would command him to hold himself in rather odd body positions while the
    chief and myself up in the wheelhouse "tuned" the radar. If possible we
    would do this in port, prefferably so the crews of other vessels could be
    witness to the charade. The tinfoil hat was always the crowd pleaser.
  17. Larry

    Larry Guest

    Darn. I never saw that trick.....(c; Thanks.

    Bored to tears crossing the Atlantic for Naples at our breakneck speed of
    17 knots, some of the boys in the DASH helo hanger got the bright idea to
    screw with the CIC watch (an oxymoron in a tender with 2 3" cannons the
    gummer's mates have to break out the manual to fire). They built a tin
    foil kite out of Reynolds Wrap stolen from the galley, a really nice box
    kite with fiberglass spars. The DASH helo deck was above our fantail and
    a great place at sea to fly kites, which up to this point was no problem.
    They had about 3 miles of some exotic monofilament line with an amazing
    tensile strength, but little weight/mile.

    After darken ship (why we did that was always a mystery), when you
    couldn't see it, they flew the kite behind Everglades and payed out lots
    of this tiny line. The kite was quite large and had a lot of lift. It
    would fly back until you could hardly see it, its line seemingly trailing
    off to nowhere. Flying above the fantail watch, who was looking at the
    horizon, not for the Luftwaffe above, he reported nothing. Not so the
    radar operator in CIC. He sounded the alarm of a UFO trailing the ship
    on the Raytheon Pathfinder (SPS-21) display at about 2 miles. The watch
    reported no sighting as the kite was too far away by the time he looked
    for it. The ship's log was duly noted and everyone aboard, mostly the
    enlisted ratings who knew all about what was going on, was told to keep a
    sharp eye.

    Every night, for over a week, this "thing" would show up on radar in the
    dark and trail the ship for hours...Then, just after midnight, it would
    approach the ship and disappear, suddenly, off the radar less than a mile
    away, undetectable.

    Finally discovered what it was by the Comm Officer who observed its
    launch from the deck outside Radio Central one night, the jig was up.
    The airdales on the helo deck apologized and said they'd been flying many
    kites. This one was just new. They pleaded innocent, which they
    weren't. Our captain decided it was a great test of CIC efficiency, an
    unintended drill of great success. The kite continued to fly, but with a
    new Saran Wrap covering that was radar transparent, compliments of the
    Chief Radarman and cooks....(c;

  18. Jack Erbes

    Jack Erbes Guest

    Sea stories? Oh boy! Now this one is a no shitter. In 1965, up on one
    of the westernmost islands in the Aleutian chain, we used to send guys
    outside with a compass, a pair of binoculars, and a notepad, to watch
    for the Russians making overflights.

    They were told the aircraft would be either GU11's or B1RD's and to note
    the number of aircraft in the flight, relative bearing, and approximate
    distance. Sometimes we'd use two guys and one of them would be a runner
    to bring the reports back in where they were plotted and tracked on a map.

  19. Larry

    Larry Guest

    If you ever get access to a milspec AN/xxxxx chart that shows what the
    letters stand for in AN/ electronics, look up:

    AN/ABB-(put your fav number-letter here)

    ABB amounts to the model designation for a carrier pidgeon....(c;

    Just to see if anyone ever really READ the data from a 2Kilo, we did some
    maintenance on AN/ABB-3A, S/N B283845 located at the frame number/deck
    level of our flag storage locker atop the main deckhouse. We even turned
    in 2Kilos announcing we had completed Field Changes 1 through 12, but not
    13, 14 or 15 due to deployment (we hardly left the dock as a tender).

    The computer added it to the ship's equipment listing on the Z-fold
    printout and listed it as needing 6-month updates, which we always filled
    out 2Kilos for and turned into the 2Kilo center...trying to keep a
    straight face.

    I often wondered what the decommissioning outcome was when they couldn't
    locate this expensive piece of equipment to toss into the dumpster. We
    never reported he died or was lost at sea flying back to Charleston...(c;

    Oh, obviously, noone ever actually READ any reports we sent in.....

  20. Jack Erbes

    Jack Erbes Guest

    That was it. I worked out at the AAFJOG on Shemya for about 8 months in
    1966, we were a small detachment from NAVCOMMSTA Adak.

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