16' Series Blown tv

coys 53

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Hi guy's
I have just fitted a cigarette lighter socket to the van direct to the van battery complete with an inline 10amp fuse. When I plugged the tv into the socket it blew the tv. Checked the socket with another appliance it worked fine. Do you think it could be the 12v lead not being compatible with the tv that caused the tv to blow
 

mikerezny

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Sep 11, 2016
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Hi guy's
I have just fitted a cigarette lighter socket to the van direct to the van battery complete with an inline 10amp fuse. When I plugged the tv into the socket it blew the tv. Checked the socket with another appliance it worked fine. Do you think it could be the 12v lead not being compatible with the tv that caused the tv to blow
Seems more likely that you reversed the polarity when you wired the socket.
How did you check that positive was on the centre pin and negative on the outer sheath?

Otherwise:
Has the TV ever been plugged into any cigarette lighter socket and worked correctly?
Was the lead that went from the TV to the cigarette lighter plug supplied with the TV?
What sort of connector was on the end of the lead that plugged into the TV?

cheers
Mike
 

coys 53

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Hi Mike
Yes the socket is correct I plugged a separate unit into the socket and tested with a multimeter clocked 13.2 v. What is baffling me is why the fuse didn't blow yet the tv did
Alan
 

Boots in Action

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Mar 13, 2017
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Hi Mike
Yes the socket is correct I plugged a separate unit into the socket and tested with a multimeter clocked 13.2 v. What is baffling me is why the fuse didn't blow yet the tv did
Alan

@coys 53 , another "silly" question possibly: is the tv set a 12 volt stand alone type ie. is it suitable for 12 volt operation only?? Or can be operated on 240 volt WITH a stepdown 12 volt DC transformer?? As @mikerezny stated, correct polarity is absolutely essential although the good tvs have diode protection to prevent damage in the event on incorrect connections. Checking with a multimeter is great, but it is not the voltage in this case. Is the centre pin contact on the plug positive?? The 12 volt plug usually has a quick blow fuse inside. What was the value of that fuse? For a small tv, I would think that it should not be more than 5A if tv only draws 3A. A 15A fuse may not blow before a lot of damage can be done to tv internals. The voltage and current (either amps or probably watts) will be shown somewhere.
 

mikerezny

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Sep 11, 2016
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Hi Mike
Yes the socket is correct I plugged a separate unit into the socket and tested with a multimeter clocked 13.2 v. What is baffling me is why the fuse didn't blow yet the tv did
Alan
I wasn't there and the TV is not in front of me. So, it is hard to diagnose what happened and what might have caused it.
Don't worry about why the fuse didn't blow. That would appear to be the least of your worries. Automotive fuses are slow blow, which means a much larger current can go through them for a short period of time and they won't blow. Electronic components can be damaged long before an automotive fuse will react.
Sometimes, there is a fuse in the cigarette lighter plug. It might have been a lower rating and has blown instead of your 10A fuse.

Now, back to your problem. I asked quite a few other questions in my previous post to help eliminate what might have been the cause.

cheers
Mike
 

mikerezny

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good tvs have diode protection to prevent damage in the event on incorrect connections
That is indeed true. However, manufacturers typically don't put a diode in series with the lead since that would result in a voltage drop and require a diode rated high enough and require heatsink to keep it cool, increasing the cost. More often, they put a diode ACROSS the power supply lead so normally it isn't conducting but conducts if the polarity is reversed. The resulting high current means that any protecting fuse blows very quickly. In some instances, that diode is damaged in that instance and becomes a short circuit.

cheers
Mike
 
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coys 53

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Thanks Mike
I have purchased a new tv along with the 12v lead to suit, it is also 240v, I will change the inline fuse to a 5amp as suggested and will double check the port.
Alan
 

coys 53

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Sorry Mike
Did have a lead never used it
Never had it plugged into a cigarette lighter socket
Was a round (4/5mm) think they call them a 2.1
Never planned to go off grid, now do.
 

mikerezny

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Sorry Mike
Did have a lead never used it
Never had it plugged into a cigarette lighter socket
Was a round (4/5mm) think they call them a 2.1
Never planned to go off grid, now do.

Those 2.1mm or 2.5mm plugs do not have a standard. +ve can be on either the centre or the outer. Have a look at the socket on the tv, it should identify the polarity of the centre pin. Then use your multimeter to confirm that the lead is the correct polarity when plugged into your car socket and again in your caravan socket.

cheers
Mike
 
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Boots in Action

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Those 2.1mm or 2.5mm plugs do not have a standard. +ve can be on either the centre or the outer. Have a look at the socket on the tv, it should identify the polarity of the centre pin. Then use your multimeter to confirm that the lead is the correct polarity when plugged into your car socket and again in your caravan socket.

cheers
Mike

Yes Mike @mikerezny , the use (or misuse?) of a 2.1mm or 2.5mm plug changes everything as there is normally no room for a fuse at that end. The normal cigarette plug is much bigger and can fit a fuse inside plug, but not a diode which would be on the input circuit inside the tv. Incorrect polarity is usually the problem as some leads have interchangeable tips which allows one to change pins around to suit. I have a couple of these in my van spares in case I have a lead where polarity has to be changed to suit appliance although most now require a USB type plug.
 
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Boots in Action

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Thanks Mike
I have purchased a new tv along with the 12v lead to suit, it is also 240v, I will change the inline fuse to a 5amp as suggested and will double check the port.
Alan


Hi @coys 53 ,
No need to change fuse if purchasing new tv and proper lead. You can check the current draw by looking at the spec plate or instruction booklet. What might be worth looking at is the fuse protecting that particular circuit in your van. In my van, I removed two of the 10A fuses at the main distribution point and replaced them with a 5A for the water pump circuit and a 3A for the circuit protecting the computer fans in my 3 way fridge. Pump draws 3A and computer fans, if all running at the one time, a total of 1A.
 

Drover

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Just to be curious, you said the TV blew, How ?? Did it flash and smoke or just didn't run ?

Plug the old lead into cig socket then stick the multi meter probes in the other end and see if there's any juice....... New TV probably a good idea anyway so its all singing and dancing, I would get one of the Aldi ones they work very well and don't cost a fortune like the ones advertised for vans.
My TV, STB's are all running on 12v all the time so not stuffing around changing set ups, though they will have the cig sockets changed in the fullness of time as they are a rubbish connecter.
 

Drover

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Well thats a sure sign, once upon a time I know someone plugged in the wrong lead and similar happened with a VHF radio, mucho smoke.
My next TV for van will have an optical cnx, 2xUSB and at least 2xHDMI then everything can plug in and no ginning around with cables, at present I use a HDMI splitter which is good but means another damn remote........
 

coys 53

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Thanks Drover
When you say you are changing the cigarette ports, what are you changing to
Alan
 

Drover

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Thanks Drover
When you say you are changing the cigarette ports, what are you changing to
Alan

That is the question, I just don't know I've thought of just hard wire the TV and cables for the Vast and Fox boxes or a 2 pin socket or a Uni/DiN/Merit Plug whatever you like to call them, they provide better fitting and contact than a cig socket, just the cost of buying a heap of them puts me off...not a drama if the item stays in the one place but if you use them elsewhere like in a vehicle then you need to be able to plug in, but they are heaps better..
..http://www.12volt.com.au/redirect.html?a=/General Htmls/webcat2003/plugs2.html


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