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problem with simrad radar - or mount...
"Bruce in Alaska" wrote in message ... In article , David Rinnan wrote: Hi Jani, Lost Bearing, bearing pulse error etc. sounds to me like loose connection with the cable connecting transmitter and display unit. I would check the cable connections inside the radome at first. Secondly it could also refer to power outage at the transmitter, I have encountered this problem with both Raymarine and Simrad radars. Mostly it occurs in sailing boats when battery level is getting lower but is still enough to power the display. Only thing you get is the lost bearing pulse which means that antenna is not rotating. But back in to your case, with rough seas loose cables inside connectors can cause this problem. Try to pull each wire separately to see wheter they come out, but better if there is warranty you can let others do it. /Jani One thing to look at very closely, is the way the bearing information is being generated in the Antenna Unit. In the 2nd and 3rd generation Furuno Units, the antenna bearing information was generated by a "Chopper Wheel" with an LED OptoPickup looking thru the Chopper Wheel holes. This generated pulses, are equated to an angular rotation of the the antenna. If the seal leaked on these type units and some of the the Chopper Wheel Holes filled with moisture, they wouldn't allow the LED InferRed Light thru to the Pickup and pulses would be missed, and cause the Mechanical Servo Motor that turned the Yoke coil to slow down and the picture would rotate backwards. On 4th and 5th Generation Radars, with Digital Displays, if the Pulse Stream coming from the Antenna Unit is loosing pulses, the CPU that Generates the display can't figure out how to display the receive data, and has an Error Routine that does just what the OP discribes in his second post. Hitting the "Clear Button" causes the CPU to wait for the next "Heading Flash" and then start the routine that displays the Radar Data, from Heading Flash, clockwise at the angular Pulse Rate of the Bearing Pulses. Should some of those pulses come up missing, and the next Heading Flash, not come with the right timing, then the CPU will jump to the Display Error Routine again, and you start all over again. Sometimes "Older" is better, and the old analog display would at least give you a picture even if the display went backwards a few degrees per revolution. Digital Displays can't do that, because of the way the CPU has to display the data. Look at the way the Bearing Data is generated, and look for missing pulses in that system. Bruce in alaska I know Old Chief Lynn has seen the above senerio.... -- Hey, Bruce, or when the "toilet bowl" filled with water, rust flakes falling into holes in the encoder disk, or when the encoder disk was rubbing on the optical pickup and filled some of the holes with a little black plastic dust, or when the encoder wheel holes were round and were nearly impossible to align with the optical pickup's beam...... oh, yeah, Bruce.... those were the days when troubleshooting was easy money (not)! Old Chief Lynn |
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