# another electrical puzzle



## cabby (May 14, 2005)

We have two 12v sockets in the van,( never enough is it), when I plug an insect killer into either of the sockets the nice blue light comes on and I know it is working. However when I plug our Avtex TV into one of the sockets, which happens to be the one in the TV cupboard, it does not work, but plug it into the other and hey presto it works.Now has anyone got ideas as why those little gremlins could manage this. :roll: :roll: 

cabby


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## DABurleigh (May 9, 2005)

Yes, too thin wiring or poor connection in the leisure-battery-to-socket cable.

Dave


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## cabby (May 14, 2005)

Thank you Dave, I did wonder that, but I have never used both sockets together.will get dealer to fix it when we have habitation check soon.with other niggardly items.

cabby


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## cabby (May 14, 2005)

Thought I had better add that the rest of the van is lovely, just in case everyone thought I was not happy with it.

cabby


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## clodhopper2006 (Aug 13, 2006)

If your telly works in the second socket but not the first it suggests to me that the first socket is faulty. maybe just a loose wire in the terminals.

Bob


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## DABurleigh (May 9, 2005)

What powers the insect killer light then Bob?


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## clodhopper2006 (Aug 13, 2006)

Ooops missed that bit. Ok then, when you have the telly plugged in are you able to measure the voltage at the plug to the telly. It's probably as the others are saying - too much volt-drop caused by too thin cables


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## legend654 (Mar 28, 2006)

Could one socket be connected through an inverter? We have four sockets, two of which run from the inverter. Just a thought.


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## Codfinger (Jan 11, 2008)

*gremlin*

Just a thought...........................have you checked the polarity of faulty socket?? :idea:


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## cabby (May 14, 2005)

Now there is an interesting thought,codfinger, but would it make any difference on a 12 volt socket.
this was only using one socket at a time during this test.so to re-cap,
both sockets will work the fly killer, and give me that lovely attractive BLUE light. :roll: :roll: one socket will power the TV, but the second socket fails to power the TV.batteries have over 12.6v reading.nothing else is switched on. :idea: :idea: :idea: :idea: more than welcome.

cabby


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## Codfinger (Jan 11, 2008)

I was just thinking that a light will work no matter what the polarity is (unless its l.e.d) but the tv wont work with the wrong polarity do you follow? btw i hope there is a voltage stabiliser inline for the tv?


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## rayc (Jun 3, 2008)

There is a high resistance in the socket e.g a poor joint / bad connection or faulty socket .
When you use the flykiller very litttle current is drawn so there is minimal volts drop. When you use the tv much more current is drawn through the high resistance and there is a large volts drop.


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## Codfinger (Jan 11, 2008)

Sounds technical :? call in the a-team :!:


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## rayc (Jun 3, 2008)

cod finger, I live in Corfe Mullen, nice to see another member on here living locally.
Ray


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## Codfinger (Jan 11, 2008)

Hi ray,is that you near the thatch cottage?


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## rayc (Jun 3, 2008)

cod finger, No I know where you mean but I am further up towards Springdale Road. Ray


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## aido (May 17, 2005)

*post subject*

I intend to fit a second tele. in the MH My question is can I chop off the transformer and wire up the rest of the wire to the 12 volt circuit. 8O

Aido


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## pneumatician (May 1, 2005)

*Electrics*

Could the polarity be wrong ?? With some items polarity is irrelevant perhaps with your TV it isn't.

Check with a meter.

Steve


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## AberdeenAngus (Jul 26, 2008)

*Re: post subject*



aido said:


> I intend to fit a second tele. in the MH My question is can I chop off the transformer and wire up the rest of the wire to the 12 volt circuit. 8O
> 
> Aido


Afraid this falls into the category of...."if you have to ask the question, you're not qualified to do it".


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## aido (May 17, 2005)

*Re: post subject*

[
Afraid this falls into the category of...."if you have to ask the question, you're not qualified to do it".[/quote]

Do you have an answer to my question or are you just the MHF expert on qualifitations 
Aido


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## hilldweller (Mar 8, 2008)

*Re: post subject*



aido said:


> > Afraid this falls into the category of...."if you have to ask the question, you're not qualified to do it".
> 
> 
> Do you have an answer to my question or are you just the MHF expert on qualifitations
> Aido


He just happens to be right. You don't know what is coming out of that "transformer" and if you ask the question it indicates that you don't have the tools or knowledge to to check it out.

The only answer, given your facts, is MAYBE. So "are you feelin' lucky punk?"


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## aido (May 17, 2005)

*Re: post subject*

[q
He just happens to be right. You don't know what is coming out of that "transformer" and if you ask the question it indicates that you don't have the tools or knowledge to to check it out.

If it's a 12 v transformer one would not have to be a rocket scientist to know that the power coming out is 12v.
AIdo


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## 103356 (Mar 11, 2007)

*Re: post subject*



aido said:


> [q
> He just happens to be right. You don't know what is coming out of that "transformer" and if you ask the question it indicates that you don't have the tools or knowledge to to check it out.
> 
> If it's a 12 v transformer one would not have to be a rocket scientist to know that the power coming out is 12v.
> AIdo


It may be 12v, but the 'transformer' you cut off may do more than just changing the voltage - it may have regulators and smoothing and ripple filters in. Take those away and the straight vehicle power (which can also be higher than 12v, as well as fluctuating when other devices are switched on, or the charger kicks in) may not necessarily be suitable for the device being powered. Is the existing power supply a 'constant current' one, or an 'unregulated' one? These are the sort of questions you need to know the answers to - hence the previous comment.


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## sallytrafic (Jan 17, 2006)

*Re: post subject*



aido said:


> [q
> He just happens to be right. You don't know what is coming out of that "transformer" and if you ask the question it indicates that you don't have the tools or knowledge to to check it out.
> 
> If it's a 12 v transformer one would not have to be a rocket scientist to know that the power coming out is 12v.
> AIdo


Don't take offence Aido but to say the 'power' coming out is '12V' shows that your electrical knowledge *may* be a bit limited. Power is as you probably know measured in Watts. Current comes out of a transformer. However that may be harsh because I have heard plenty of time served electricians use phrases like that.

However the others are right as well if you don't know the spec of your television with regard to the acceptable range of voltage that it can be connected to you may do damage. In an unlikely extreme this may cause the set to catch fire.


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## hilldweller (Mar 8, 2008)

*Re: post subject*



aido said:


> If it's a 12 v transformer one would not have to be a rocket scientist to know that the power coming out is 12v.
> AIdo


Some people just don't know when a hole is deep enough 

Rocket scientist, no, electrician yes.

Your 12V "transformer" could be outputting:

Regulated 12V DC

Raw 12V DC.

Smoothed 12V DC which will be nearly 20V.

12V AC - This is all a true transformer can output.

Only one of the above is compatible with your MH "12V" which is not 12V at all.

So the answer is still MAYBE.

Sorry, but just because it looks easy does not mean that it is.

=====================

Anyway, this is MHF not a boxing ring, lets try and be helpful.

>> I intend to fit a second tele. in the MH My question is can I chop off the transformer 
>> and wire up the rest of the wire to the 12 volt circuit.

This wire of yours, does it plug into the TV ? Does the TV say 12V DC next to the socket ? If it does there is a regulator you can buy that plugs into the MH 12V ( which is 11 to 15V with occasional spikes much higher ) this outputs a regulated 12V DC which is safe for the TV.


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## AberdeenAngus (Jul 26, 2008)

I smell a Troll !


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## clodhopper2006 (Aug 13, 2006)

*Re: post subject*

quote]

Don't take offence Aido but to say the 'power' coming out is '12V' shows that your electrical knowledge *may* be a bit limited. Power is as you probably know measured in Watts. Current comes out of a transformer. However that may be harsh because I have heard plenty of time served electricians use phrases like that.

.[/quote]

Hmmm, well actually Frank if we talk about current coming out of a transformer we have to say power does too. Firstly current is a product of a voltage applied to a resistance (we'll not complicate it by mentioning inductance or capacitance) and so you get a higher current if you have a low resistance. Now given a specific current flow in a circuit - say 1A and 12V we have a power draw of 12w. The resistance would be 12 ohms (R=V/I)
Now if our circuit has two 6 ohm resistors in series then the total power would be split evenly between the two (I squared R) so the power is delivered to the load and so must come out of the power supply.
The voltage is also applied to the load and in the case of our two 6 ohm resistors volt drop across each is 6v (Vd=IxR).

Sorry for being a smarta**e 

Bob


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## ICDSUN (Oct 10, 2006)

*Re: post subject*



aido said:


> I intend to fit a second tele. in the MH My question is can I chop off the transformer and wire up the rest of the wire to the 12 volt circuit. 8O
> 
> Aido


Aido

The answers are all relevant, it depends on the true output etc.

I tried the same as you propose, 17" LCD with a 110/220VAC 12VDC transformer, split the cable and it all works from 12v sockets when on hookup but tv won't power up, only to standby when on batteries 2x 110amp alone. Panel display =12.8VDC & battery at terminals 12.9VDC voltage with no load on cable connector is 12.75 VDC, so in theory it should work but it does not.

Just use a small 150w inverter for the telly less hassle

Chris


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## sallytrafic (Jan 17, 2006)

*Re: post subject*



clodhopper2006 said:


> sallytrafic said:
> 
> 
> > Don't take offence Aido but to say the 'power' coming out is '12V' shows that your electrical knowledge *may* be a bit limited. Power is as you probably know measured in Watts. Current comes out of a transformer. However that may be harsh because I have heard plenty of time served electricians use phrases like that.
> ...


You might like to read my post again more carefully  at no time do I say that the power doesn't come out of the transformer. My placement of punctuation was quite deliberate. However if I had said 'Current not voltage comes out of a transformer' that might have been better.

PS I've corrected your 'quote' BBCode in my quote so it looks right.


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## AberdeenAngus (Jul 26, 2008)

Current out of a transformer is zero (on average), volts out is zero too (on average), therefore surely average power must be zero too             


and before the pedants put me right.........I'M ONLY JOKING !


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## aido (May 17, 2005)

*post subject*



AberdeenAngus said:


> Current out of a transformer is zero (on average), volts out is zero too (on average), therefore surely average power must be zero too
> 
> and before the pedants put me right.........I'M ONLY JOKING !


I was also joking having got a new Camos and 15" TV fitted by wwwAertec.net who does a great job.
But as they say here in Ireland It was good to see the reaction.

Aido :wink:


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