Reverse Polarity- Stereo not working

[melby]

Hey all
I have a 71 Avion camper parked at an RV more or less year round. I have a car radio hooked up and shortly after I moved into the park, the stereo stopped working. My control panel read "Reverse Polarity". I know a little about the topic, but nothing else has been affected. No shocks, or appliances frying. Any clues?

[akronharry]

I have an Airstream that had a similar issue. When I turned on my stereo I would hear a loud humming sound. Turned out my house batteries were fried and once they were replaced, the humming sound went away.

[wa8yxm]

Likely not related.. The "Reverse Polarity" on the control panel refers to a swap of the hot and neutral leads on the shore power cord.. On a 30 amp rig (or a 50 amp adapted to 30) This will not harm the RV in any way.. Might harm you (anything from a mild shock up to and including death is a possible complication of reverse polarity) but it will not harm the RV or any device within it.

Now had it been the 12 volt side of life.. That can harm the radio.. but most likely blew a fuse.. However reverse polarity on the shore power (What your panel was telling you) is harmless to the RV.

[Chris_Bryant]

CA Traveler wrote:


But that light could come on due to bad connections cause abnormal voltage drop on one of the wires - that is enough voltage for the light to work.

That's my thought as well- the wiring hasn't changed (unless there was work done in the park), but connections get corroded.

For starters have the battery load tested at a auto store. Get the AC plug replaced, the reverse polarity light is off, make sure the battery is being charged and perhaps the radio will work.

That sounds like the plan.

[westend]

When the battery is charged, connect the radio to the battery terminals. That will tell you if there is a source issue and if the radio is functionable.

[CA_Traveler]

Chris Bryant wrote:
it's just a light hooked between neutral and ground.

True reverse polarity doesn't happen unless some wires are connected wrong.

But that light could come on due to bad connections cause abnormal voltage drop on one of the wires - that is enough voltage for the light to work.

For starters have the battery load tested at a auto store. Get the AC plug replaced, the reverse polarity light is off, make sure the battery is being charged and perhaps the radio will work.

[RoyB]

The campground/park should be wired up like this...



You can measure the three legs on the 30AMP side with a standard mulitmeter and should duplicate these readings. If not then the campground/park has a problem.

50 AMP SIDE


30AMP/20AMP SIDE


Use this pictorial on which wires go to which pins in the plugs...


Most definitely not a good idea to change your PLUG to match up with a miswired or campground/park problem. Then you will have problems when you go somewhere else... Make them fix their problem...

All of this info is available from GOOGLE SEARCH

Roy Ken

[RoyB]

bad news is going to be when you let the batteries get below their 50% charge state (12.0VDC) then they are not much good anymore when you try to charge them back... They may look like they have recovered ok but when you start using them again they die much quicker...

Roy Ken

[MEXICOWANDERER]

Yet I have seen lots of 12 volt accessories act totally nuts when voltage slumps to 10 volts or less. Best course of action is to wait, get things fixed, charge the batteries then start fresh.

[DrewE]

Don't rewire your shore power plug unless you can conclusively show that it is wired incorrectly (which would most likely be because someone incorrectly replaced the plug at some point). If the campground outlet is miswired or in poor condition, they need to fix that, and it sounds like you're on your way to get that taken care of if it needs work.

The radio may not have died from a power problem, but just happened to die. Maybe there's a cold solder joint, or an internal short, or an electrolytic capacitor that dried out, or a semiconductor that was being used barely within its ratings and didn't last well. Most RV makers put about the cheapest possible radios in.

[melby]

Thanks RoyB.

I unplugged from shore power and the reverse polarity indicator went off. However my battery appeals to be dead. I'm charging it now, but I still think it's a 120VAC issue. I did notice the plug to shore power looks like it has some damage on it. I'm going to check with the RV Park Manager now.
Am I able to re-wire the my shore power plug? Switch the Neutral and Hot. I suspect that would affect house my panel is set up. It sounds like the RV Park would have to do something on their end.

[RoyB]

REVERSE POLARITY on the 12VDC BATTERY setup has fuses to protect against things like this. The REVERSE POLARITY FUSEs betwen the battery terminals and the 12VDC distribution panel will immediately blow if the battery terminals are reversed accidentally..

Am not familiar with the panel you are referring to but it sounds like it is referring to REVERSE POLARITY on the 120VAC side of things... i.e. the three 120VAC conductors (HOT-NEUTRAL-GROUND) coming from the shore power cable side are seeing this problem and reporting at such...

I would use one of those 120VAC circuit tester plugged directly into a 120VAC receptacle and see what lights show on it...





If every thing is wired correctly only the two ORANGE LIGHTS on the bottom right will be lit up...


Roy Ken

[melby]

DrewE. Makes sense. The fuse on the stereo doesn't seem to be fried though. Is there a type of charge that can blast right past a fuse?

[DrewE]

If none of the other 12V systems are affected, I would very much guess it's unrelated. Reverse polarity in the 12V system could very reasonably kill a stereo, but it would also cause trouble with blowing converter fuses, probably causing fridge and furnace controls problems (though old ones might be unaffected in theory), and making many things with motors (like fans) turn the wrong way.

I would tend to guess that your radio just died, unrelated to other things.

Do have the outlet you're plugged into checked for swapped hot and neutral lines, though. If it's miswired, it can lead to dangerous situations, particularly in combination with other electrical faults.

[melby]

So maybe the radio is just fried, or wired wrong. It's just weird how it worked one day, then the indicator showed up, and it stopped working.