Bearing Pulse Error with R20X Radar

[Rainer]

I have an old Raytheon R20X radar, after warming up process it will start for 2 seconds and the array starts to rotate, but after this 2 second, there will be message "Bearing pulse error"!? I have understood, that this might be caused by damaged Bearing pulse generator or damaged Ship's heading marker switch? Does anybody knows which type of circuits these are and where they are located in the array??

[senormechanico]

Look for some type of pickup at the base of the rotating antenna.
Basically, each time the antenna completes a turn, it sends a momentary pulse to the electronics which tells the screen which way is up so it can display the information.

Some units use a switch, others have a Hall effect sensor (magnetic).

[fairbank56]

Do you get "Bearing Pulse Error" or "Bearing Zero Pulse Error"? Zero pulse error means a problem with the ships heading marker switch and/or associated circuitry on the power supply board in the scanner. Pulse error means no pulse from the pulse generator which is integral to the motor in the scanner. The pulse encoder is located in the lower housing of the drive motor. Bearing pulse is via the white wire in the scanner cable. Check continuity between the white wire from J101 in the scanner to pin 13 on the display plug.

Eric