Jefa DD1 screeching and fuse blown

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   11 hours into a 14 hour motorsail yesterday (Yarmouth (IOW) to St Peter Port), the DD1 started making intermittent loud screeching noises and shortly after the autopilot computer went offline. I had to hand steer the last 3 hours showed me how hard the DD1 had been working!Investigation today has identified a blown 15A fuse in the autopilot computer (not the external in-line fuse but the one on the circuit board). Replacing this fuse with a 20A has brought the autopilot system back to life but the noise remains. It sounds like dry bearings in the motor. The helm without the autopilot engaged is finger light and silent.
Question - can the top of the motor be easily removed (8 hex drive bolts) and does it reveal the suspect bearings?
Second question - can these bearings be greased to solve the immediate problem or can they be easily replaced while away from base?
Third question - any ideas who could provide the best JEFA support in Guernsey?

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High Time Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 04 September 2012 Location: Portsmouth UK Status: Offline Points: 819	Post Options Post Reply Quote High Time Report Post Thanks(0) Quote Reply Topic: Jefa DD1 screeching and fuse blown Posted: 30 June 2024 at 17:43
	11 hours into a 14 hour motorsail yesterday (Yarmouth (IOW) to St Peter Port), the DD1 started making intermittent loud screeching noises and shortly after the autopilot computer went offline. I had to hand steer the last 3 hours showed me how hard the DD1 had been working! Investigation today has identified a blown 15A fuse in the autopilot computer (not the external in-line fuse but the one on the circuit board). Replacing this fuse with a 20A has brought the autopilot system back to life but the noise remains. It sounds like dry bearings in the motor. The helm without the autopilot engaged is finger light and silent. Question - can the top of the motor be easily removed (8 hex drive bolts) and does it reveal the suspect bearings? Second question - can these bearings be greased to solve the immediate problem or can they be easily replaced while away from base? Third question - any ideas who could provide the best JEFA support in Guernsey?
	Roger High Time (415 #038)

S&J Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 30 August 2014 Location: Perth WA / Med Status: Offline Points: 1371	Post Options Post Reply Quote S&J Report Post Thanks(0) Quote Reply Posted: 30 June 2024 at 20:18
	You have my sympathy. My autopilot DD1 recently failed 8 hours into a 3 day passage. Not wanting to hand steer for 3 days, we turned back into a building storm and then faced 8 hours of 40kts gusting 50kts before finding a sheltered anchorage. Jefa diagnosed clutch failure and we ordered the parts, but after removing the base of the drive it was apparent that a small white plastic cog had shattered. With crew flying in to Malta, I decided to replace the DD (€3,000). I intend to try opening from the top to get access to the damaged part, but haven't done so yet. Access from the bottom was straight forward although I needed an impact driver for a couple of reluctant bolts. Jefa assure me the unit is designed for owner maintenance. Jefa don't have a service network so everything has to be sent back to Denmark for repair. You may find someone who is willing to effect a repair, but it won't be authorised by Jefa. Note that you are unlikely to have something as simple as a bearing requiring grease. I think you may find similar issues to mine with a gear cog badly worn or broken. I would strongly advise you to get this fixed unless you have a crew if gorillas willing to hand steer through the night! Edited by S&J - 30 June 2024 at 20:20
	H458 #159 Primal Mediterranean cruising

engineroom Members Profile Send Private Message Find Members Posts Add to Buddy List Sub Lieutenant Joined: 28 June 2024 Status: Offline Points: 24	Post Options Post Reply Quote engineroom Report Post Thanks(0) Quote Reply Posted: 07 July 2024 at 00:34
	BTW, was that 20 A fuse replaced with a 15 A fuse at some point? It is generally bad to replace a lower rated fuse with an higher value one, unless 20A was the original spec.

S&J Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 30 August 2014 Location: Perth WA / Med Status: Offline Points: 1371	Post Options Post Reply Quote S&J Report Post Thanks(0) Quote Reply Posted: 07 July 2024 at 06:21
	In my experience, the fuse that usually blows is the online furectonthe DD1 which on my boat is in the port cockpit locker, near the NAC3 computer. This fuse protects the DD1 in situations when the drive cannot counter the pressures on the rudder. I had it blow in a 56kt sqall in Sardinia in my first year and it blew a couple of times on the day the autopilot failed due to broaching. Strangely the fuse did not blow when the DD1 actually failed when I was too slow (otherwise occupied with a sandwich) to take the pilot off to hand steer through a gust resulting in the DD1 failure. I would also advise against increasing the rating of these fuses. I believe that Jefa recommend a 10A online fuse for the DD1. I have never had the autopilot fuse blow on the main switchboard so not sure what rating I have there.
	H458 #159 Primal Mediterranean cruising

High Time Members Profile Send Private Message Find Members Posts Add to Buddy List Vice Admiral Joined: 04 September 2012 Location: Portsmouth UK Status: Offline Points: 819	Post Options Post Reply Quote High Time Report Post Thanks(0) Quote Reply Posted: 07 July 2024 at 09:21
	I stripped the DD1 a couple of days ago and found nothing broken, in fact it was all pretty clean and we'll greased. However there were 2 issues that may account for the noise. Firstly the lip seal on the output shaft was very dry and may account for the screech. Secondly there were small specks of what could be rust on the top of the motor. I carefully oiled/greased these and it now run much quieter. I had the same thought re the fuses and put a 15A back on the board before retesting.The inline fuse to the autopilot computer was originally 10A IIRC and, on advice on this forum, changed it to 15A some years ago. The 15A board fuse must have been a quick blow.
	Roger High Time (415 #038)

32mike Members Profile Send Private Message Find Members Posts Add to Buddy List Commadore Joined: 26 March 2020 Location: FLorida, US Status: Offline Points: 453	Post Options Post Reply Quote 32mike Report Post Thanks(0) Quote Reply Posted: 07 July 2024 at 15:47
	I have had the one on the DC panel blow one time. There were some inexperienced sailors at the helm at the time, so I’m not exactly sure what happened there. It could have just been an instance of operator error. It hasn’t happened since and I DID NOT replace it with a bigger fuse although it was suggested. Haven’t had a problem yet with the one in the cockpit locker.
	Mike S/V Dulces Sueños 458 #087 Tampa, FL

DJgun Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 04 April 2020 Location: SydneyAustralia Status: Offline Points: 287	Post Options Post Reply Quote DJgun Report Post Thanks(0) Quote Reply Posted: 22 May 2025 at 14:50
	I Installed a brand new DD1 Jefa, a.k.a. Simrad DD15 in my 400e in about August 2020 after buying the boat and finding the drive was missing. Covid was happening at that time and so the first use was in December 2020 for about 70 hours on passage from Brisbabne to Sydney, and it worked very well, in some very windy conditions. Since then because of COVID restrictions and I'll health the boat has done a lot less sailing, and the Autopilot used for less than maybe 10 hours. Most sailing was racing, all hand steered. Late in 2024 the steering was a bit "lumpy" which I assumed was organic growth in the lower rudder bearing, which has happened before, but this time much worse. An inspection showed the Jefa DD1 was jumping when boat was steering manually. I removed the link arm and immediately the hand steering was perfectly smooth. It was not possible to manually move the output level on the DD1 with the Autopilot turned off. It should move quite easily. I removed the DD1 and checked that the drive clutch seemed to not disengage when power was off. I disassembled the Jefa DD1 and found a lot of corrosion, even though it has never been directly exposed to rain, seawater or high pressure cleaning. -Lower output bearing seized from corrision -Clutch pins seized in housing because of rust on iron bushes -Planetary annulus ring could not be rotated in housing, because of rust and no lubricant used - Pancake motor seized.. It cannot be rotated by hand. -gearing generally in excellent condition, no sign of overload or wear. -other bearings very rough turning -Electrical glands not properly tighted, and no sealant used as supplied by the factory, which they recommend for motor replacement, but don't do themselves from new. If there is any rust in the motor or other parts like clutch pins, planetary annulus,, bearings etc then it will overload the pancake motor, or at least make a lot of noise and may make hand steering more difficult. It seems Jefa design and assembly just doesn't seal the unit, so normal atmospheric changes in barometric pressures, , temperature, and humidity causes water to be inside the drive and cause havoc with corrosion. It is very disappointing. Cheers DJ Edited by DJgun - 23 May 2025 at 14:31
	DJ.....Sailor Ordinaire HIN DE-HANJ0331J708

DJgun Members Profile Send Private Message Find Members Posts Add to Buddy List Captain Joined: 04 April 2020 Location: SydneyAustralia Status: Offline Points: 287	Post Options Post Reply Quote DJgun Report Post Thanks(0) Quote Reply Posted: 23 May 2025 at 14:32
	Deleted duplicate post Edited by DJgun - 23 May 2025 at 14:39
	DJ.....Sailor Ordinaire HIN DE-HANJ0331J708



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