Kelvin Hughes VDR APT
Sperry VMFT radar image capture by KH VDR
Kelvin Hughes Mk4 downmast 25Kw Radar
Kelvin Hughes Mk5 upmast 10Kw Radar
Kelvin Hughes VDR / SVDR
Kelvin Hughes Mk5 upmast 10kw X-band radar
This ship has requested for a VDR annual performance test. Attend on board and found that the VDR give an alarm showing radar capture failed. Checked and found the X-band port radar has recently been replaced from old KH X-band to new Sperry VMFT radar. I was lucky as i have commissioned quite a lot of sperry VMFT radar so i know how to add VGA output to KH VDR image capture. Due to short time stay of the vessel, i have to find a quick solution so i asked whether i could have a spare vga cable from ship. Ship crew passed me a spare vga cable with 15pin d-sub on one end. So I cut the other end and measured the R,G,B,H,V signal together with ground, joint them together and conduct a autodetect follow by captured the radar image. It was successful with good radar picture. Please see below the VGA 15pin pinout. Only pin 1,2,3,6,7,8,10,13,14 need to be connected.
Kelvin Hughes Mk4 downmast 25Kw Radar
This ship complaint no sync, no video, no H/L, no azimuth alarm shown on nucleus 2 6000. First switch on the system and measured magnetron voltage across the magnetron lead green and yellow found 8.5Vac.
System show radar echo quite weak. So decided to replaced magnetron which already work for approx. 18months. A 25Kw magnetron will last for approximately 10,000hrs. After replacement of magnetron, switch on system and found no power on the modulator. Measured 27Vdc and 8.5Vac at power input of CTX-A4 power supply not present. It seems to me is an intermittent fault. So after replacing CTX-A4 power supply, switch on the system and found modulator was powering up normally. Since new magnetron MG5424 has been replaced, carry out setting up of magnetron current for S/P and M/P to -250Vdc. carry out setting up of magnetron current for L/P to -350Vdc.
During the adjustment, i could hear the magnetron firing sound smoothen when adjustment were carry out.
This process is necessary to prolong the life span of magnetron and prevent damage to modulator pcb as well.
Kelvin Hughes Mk5 upmast 10Kw Radar
This ship complaint display show No H/L, No Azimuth, No Sync, No video alarm on Nucleus 2 6000 Display unit. Most of the fault on No H/L and No Azimuth alarm were related to Azimuth PCB and Slotted Disc. Go up to scanner, open up the cover and found slotted disc has misalign and hit the opto couple on the azimuth pcb causing it to damage. After replacing Azimuth pcb, tested the radar and found the No Azimuth alarm gone. But other three alarms still present. Climb up the scanner again, this time i would replace the modulator pcb as no sync alarm seems telling me that magnetron has not fire. So after replaced modulator pcb, the no sync alarm has gone. Now left with no H/L, and no Video alarms. Again climb up the scanner to check for gap between slotted disc and azimuth pcb, found 2mm gap too large causing no H/L alarm. Add washers behind the mounting of azimuth pcb to reduce the gap to 1mm. So this time, no H/L alarm gone. The last alarm was the most difficult to solve. Climb up the mast again to replace receiver pcb. I was quite lucky consider i have change the correct spares by guessing what could be wrong. All alarms were gone, but not the end of the story yet. I could not tune the radar and weak echo was shown on screen. LNFE(Low Noise Front End) seems to be the choice since no tune control was observed. This time i hit the jet pot. After replaced the LNFE, full pictures with strong echo had appeared. The reason for so many parts failed at the same time not because Kelvin Hughes radar were unreliable. It was because ship owner had used third party technician who were not trained to service Kelvin Hughes equipment. The disaster started when the technician installed a new magnetron not compatible with the mounting on the MK5 upmast radar. Please see pictures of JRC magnetron fitted on MK5 upmast. Looks weird.
Kelvin Hughes VDR / SVDR
I am very glade during my career with Kelvin Hughes between year 2003 and 2007 i was given a chance to commission, service and attend APT for one of most stable VDR / SVDR in the world as compare to other maker. As Kelvin Hughes has entered into VDR / SVDR market very much early than their counterpart when IMO regulation takes place. It has make Kelvin Hughes secure a wide market share for VDR/SVDR in the shipping industry.
The capsule or CSM(Crash Survival Module) has a wide range of different types from Smith module to L3(HVR) to Jotron Floatfree module. Please see attached pictures of CSM.
Kelvin Hughes Mk5 upmast 10kw X-band radar
This ship complaint that radar keep rotating even operator select standby mode.
Attend and found that when switches the radar off and on, it takes 3mins warm up for magnetron to heat up. Then selecting transmit will only make the scanner rotate and transmit the pulse out. So measure at display input pcb for any state change on Tx/Stby line. Found that state change is present. So the problem may not be at the display side. Went up to scanner unit, open the front cover, observe the soft start pcb physically. Found burnt mark on one of the resistor. Also found IC1 faulty using multimeter to measure in diode mode.
Replaced soft start pcb and restart the system. This time, the scanner will only rotate when operator select transmit mode. Switch off and on several times to make sure it works well.
Please see attached pictures of soft start pcb.
