Changover Trouble(120v-12v)

[73ANDY]

Okay, I just hooked the radio back up that was under the Control Center in the front of the trailer. It was included with the trailer from the original owner(3 years ago), but I never took the time to hook it up. Well it works and sounds great, however, when I unplugged the 120 volt 30 amp plug from shore power, my 12 volt power didn't kick in. Huuuuummm? Well I dinked around and pulled the 50 amp fuse (on the wall next to the univolt) on the negative side out and tested it and it was fine, but when I put if back in, walla, my 12 volt system was back. Weird???? Well I thought let's see that again, so i plugged the 120 volt line back in and everything was normal, then I unplugged the 120 volt line and my 12 volt disappeared again! So I pulled the 50 amp fuse out and put it right back in and everything worked! Soooooooooooooooooooo.


Any ideas on what is taking place here? Should I assume there is a problem with the Radio, should I disconnect it again and see if my 12 volt works normally. If at this point my 12 volt works normally, what do I do about the Radio wiring????

Help!!! I can sure do without the Radio, but it would be nice to have since there is a spot for it and there are already built in speakers.

Thanks in advance for any insight into this wiring problem!

[Pick]

Sounds like a dirty or intermittant fuse holder to me. In john hd's thread about the Univolt someone made mention of a "cooked" fuse holder, not sure if that is the same one you are talking about, but worth looking into. I do not believe the radio could be causing this.

[femuse]

Mike mentioned that the board the fuses were,ended up breaking down from cooking. But he never had a problem with the 50A, it was the fuses for individual circuits. Everything cooked over the years (1974 to 2000)

[73ANDY]

My 50 Amp fuse holder for the Negative leg is totally seperate from the other fuses, it is not even inside the univolt. It is mounted on the outside wall just to the left of the univolt.

I agree it seems unlikely that the radio is causing the trouble, but it didn't seem to happen until I hooked up the radio. I will take the time to disconnect the radio and see if this changes the scenario at all. I just have had the time yet to do this.

I will update as soon as I have taken the radio out to see if this stops the problem.

Until then(probably friday or saturday) if anyone has any other brainstorms please feel free to input.

[Chas]

Could it be that you have the radio connected to the wrong circuit, say the feed for the 120 volt indicator lamp on your control center, or one of the other devices in the control center? Seems there is something getting switched off whenever you disconnect the 120 volts, sorta like a transfer switch that is not kicking over to battery power? This is a weird one which at first I would attribute to intermittent problems such as the "cooked fuseholders" I had on my Univolt. They drove me crazy, lights, no lights, lights, no lights! But, yours seems too predictable for that.

Chas

[femuse]

They drove me crazy, lights, no lights, lights, no lights!

Well, Chas, Mike is very unhappy he did not "meet" you before.

You could have saved him a lot of trouble, while he tried to make those *%#@ lights work.....for a while.

He remembers fondly the many years he had to take the bed apart, then squeeze most of his upper body under there, to what looks to him like a very long narrow tunnel to under the bath tub.

Wasn't that fun?

We really miss our Univolt. It sits in a building near by, and we go and kick it from time to time.