Rich,
You are correct. Reverse polarity will apply a massive forward current through the diode bridge in the rectifier assembly. Usually the diodes melt forming a short circuit. That can actually be a good thing because it may protect other electronics by limiting the reverse voltage. Hope your friend was lucky and nothing else was on. It may well have killed the regulator IC too. I don't know who makes Yanmar's alternators (probably Hitachi or NipponDenso) but it is quite possible that a good auto-electric shop can replace the diode assembly and regulator and then test. Probably easiest solution is to source a new or rebuilt alternator. Here is one supplier he could try: <http://www.motorcityreman.com/marine-electrical-units-alternators.html> http://www.motorcityreman.com/marine-electrical-units-alternators.html Mike Dean C&C 27 Mk III Oakville, ON From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of David Paine Sent: April-06-13 9:24 PM To: cnc-list@cnc-list.com Subject: Re: Stus-List Yanmar panel problem ... Actually, I thought that the alternator diodes were a likely possibility. I told Steve (who really should join this list) that he should pull the alternator and have it tested at NAPA. Cheaper than a Yanmar wrench! On Sat, Apr 6, 2013 at 9:16 PM, Knowles Rich <r...@sailpower.ca> wrote: You may be right, Dwight, but someone knowledgable should troubleshoot it properly. Rich Knowles Indigo. LF38 Halifax On 2013-04-06, at 21:51, dwight veinot <dwightvei...@hfx.eastlink.ca> wrote: Rich I think that is good advice but would it not be reasonable to suspect something simple like the oil pressure sensor is causing the alarm Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS _____ From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Knowles Rich Sent: April 6, 2013 9:18 PM To: cnc-list@cnc-list.com Subject: Re: Stus-List Yanmar panel problem ... I strongly suggest your friend get someone familiar with things electrical to check out his boat. There are simply too many possibilities to discuss them sensibly here. Rich Knowles Indigo. LF38 Halifax On 2013-04-06, at 20:45, David Paine <paineda...@gmail.com> wrote: Folks, My friend, Steve, messed up this afternoon working on his cb C&C 35. He is too shy to post (kidding) but here (below) is his question. I am an A4 guy so I am clueless about what dangers the Yanmar horn that sounds when starting a Yanmar is even supposed to alert one to! Here is the question ... Hi David - I have a question for you ... this morning, while installing the boat batteries, I installed the big (engine) battery then proceeded to cross the wires on the second (house) battery ... resulting in a pretty spectacular spark. After the spark I noticed two other things - 1) the first battery was making pulsing noises that sounded like it might be shorting out internally - I disconnected it and, when it was tested later, the battery was dead ... it was actually having charging issues last summer so I guess the arcing did it in (?) 2) when I had the battery switch "on" (to any position - "all", "both", "#1" and "#2") the Yanmar engine start panel was making the same steady tone it makes when starting the engine ... for this, I tried replacing the ignition switch but that didn't correct the problem ... it still whines on all battery positions except for "off" ... do you have any ideas (or ideas where I could get some ideas)?? _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _____ No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2240 / Virus Database: 2641/5728 - Release Date: 04/06/13 _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
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