Wiring problems (I think)?

Coach T · Posted: Mon Dec 22, 2014 7:17 pm Post subject: Wiring problems (I think)?

Today I installed a stereo, two speakers, VHF radio and antenna. I connected the stereo and VHF to a dedicated circuit on the bus. The stereo played great and the VHF turned on and seemed to do well until I pressed the mic on the VHF. At this time the stereo went crazy, volume went up, channels changed and a weird sound thru the speakers. I tried to diagnose the problem by disconnecting the VHF from the bus and wired it direct to the battery. Same problem persists. I disconnected the VHF completely and the stereo works fine, until I turned on my Nav lights the unit then turns off. It also does the same when I turned on the Port wipers and the same when I turned on the bilge. The only thing I haven't tried is directly connecting the Stereo to the battery (not BUS). By doing some research I see that others on the Web have ran into this same problem but I cant find a answer. Most of the responses talk about installing a RF filter but they don't say anything about the other components being turned (such as the bilge) and having a power problem. Any suggestions? I know many of you have stereos and many more electronics. By the way I have a Garmin 740 installed and I haven't had any problems but It also turned off when I turned on the bilge. I plan to diagnose problems again tomorrow with my fingers crossed.
Thanks

Ray · Posted: Mon Dec 22, 2014 8:13 pm Post subject:

Sounds like maybe a ground problem. Did you connect a really good ground to the radio and/or it's case?

Coach T · Posted: Mon Dec 22, 2014 8:23 pm Post subject: wiring problem

I'm not sure if I did or not in hindsight. I don't think the unit has a direct ground it has a positive and negative wire which I connected to the bus. Do most stereos have another ground?

Ray · Posted: Mon Dec 22, 2014 8:56 pm Post subject:

If I remember right, most have a screw stud on the back of the case that is the main ground [used to get strapped right to the frame of a car installation] - but the newer units might be different.

ghone · Posted: Mon Dec 22, 2014 9:51 pm Post subject:

You can power the devices from a positive and negative buss bar without grounding the frame of the stereo (like a car). Two leads come off both units. Be sure the vhf antenna is several feet from the stereo. Some installs seem to want the antenna lead for the vhf separated from other equipment wires. Had a boat one time that had the vhf antenna lead beside the auto pilot wiring , boat would do a 360 when you pushed to talk. Exciting the first time it happened! Ran the antenna down the other side of the boat and fixed it. My vhf and stereo are side by side and wired to a pos and neg buss with the vhf antenna at the back of the pilot house and no external stereo antenna. It works just fine. I'd try moving your antenna (vhf) first to see if that helps.

ghone · Posted: Mon Dec 22, 2014 9:52 pm Post subject:

duicate post

jennykatz · Posted: Wed Dec 24, 2014 8:43 am Post subject: elec problems

We had an electrical problem We would be running at 4500 rpm and turn on trim tabs and the chart plotter would turn off .there was to much power being taken off the Pos. Bus bar . With additions of 2 chart plotters ,stereo,VHF radio, wipers, everything off that Bus bar . So I added a number 10 gauge wire to battery from Pos. Bus .No more elec problems .I did the same with the tundra fridge I upgraded the wire from 12 gauge to 10 gauge .BTW I have 2 105 amp hour batteries series 27.I usually run the battery charger about once a month its a 10amp charger 2 5 amps to each battery . We use the boat all year long put about 100-120 hours a year on it . I usually replace 1 battery every couple of years .

Coach T · Posted: Wed Dec 24, 2014 3:13 pm Post subject:

Thanks all for the help. I am still diagnosing the problem but I think I have one portion solved. Jenny Katz suggestion of low power maybe part of the problem, I didn't think about this but I ran the stereo for several hours while installing the vhf (low battery) could be the problem when I try and run too many circuits. For the other vhf amfm interference, I am going to wire the stereo direct to the battery and relocate the vhf antenna wire and hope for the best. Thanks again.