Background:
I have a portable TV which I want to add a headphone socket to.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

thoughts anyone?
M.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

Be VERY careful! Lethal voltages can be present inside a TV hours after it
is turned off. Not a job for the novice.

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

The headphone socket will incorporate a switch. There are 4 terminals on it.

You break the speaker cable at a convenient point and reconnect them,
passing through the appropriate terminals (you may need to install
additional cable if there is insufficient slack to position the socket where
you want it. The terminals are -ve and +ve feed from the amplifier, and the
switched -ve and +ve outputs to the speaker. The internal switch disconnects
the speaker automatically when a plug is inserted.

Christian.

"Michael Murray" wrote in message
m...
Background:
I have a portable TV which I want to add a headphone socket to.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

thoughts anyone?
M.

Hi Michael,

Buy one of these : http://tinyurl.com/mcgf then drill a hole through the
plastic casing to suit the size of socket, in an area that will not
interfere with any of the innards. Find the speaker wires and trim them
down or add to them until you have enough wire to reach the new socket. The
black wire will be connected to the outer part of the socket (the socket
casing) and the red wire will be connected through the two lugs on the end
of the socket. When you insert the 3.5 mm Jack Plug, the action of pushing
the plug in will separate the connection of the red wire from the main
circuit board and the existing speaker and will make the connection to the
headphone jack plug only.

This is really a simple enough job but as others have said in their replies
" PLEASE BE CAREFUL OF THE HIGH VOLTAGES INSIDE THE TV "
and be careful not to touch any of the capacitors on the PCB or you'll get a
shock that will badly burn on both the entry and exit points of your body.

Good luck with it.

Plus you will need a resistor to make the volume acceptable in your
headphones, otherwise it will be too loud.

StealthUK wrote:
Plus you will need a resistor to make the volume acceptable in your
headphones, otherwise it will be too loud.

....or for bonus points add a headphone volume control too.

--
jc

Remove the -not from email

On 5 Sep 2003 06:12:39 -0700, (Michael Murray)
wrote:

Background:
I have a portable TV which I want to add a headphone socket to.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.


*** BEWARE CHARGE IS STORED IN A TV FOR A LONG TIME AFTER IT IS
SWITCHED OFF, STAY AWAY FROM THE BACK OF THE TV TUBE ***

I did this to my cheap Matsui TV 15 years ago.
No need for a switch the headphone socket cuts the sound to the
speaker as it has 4 terminals.
My TV died 5 years ago, sound played up just before it totally packed
in, don't think it was connected with my mod.

Chris

Background:
I have a portable TV which I want to add a headphone socket to.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

Is this just for your personal tv? If so you are probably ok with the advice
from the other posts. But I do remember the technician at my university
language lab telling me that when he did the tv's there, he had to install
isolating transformers between the headphone socket and the speaker wires (I
guess due to the possibility of live chassis).

On 5 Sep 2003 06:12:39 -0700, (Michael Murray)
wrote:

Background:
I have a portable TV which I want to add a headphone socket to.

Plan:
Open TV.
Find wires (probably just 2, I doubt it a 14", £80 TV has stereo)
Add chassis mounted switch to the live (?) wire.
Add chassis mounted headphone socket to the casing
Wire the socket to the other 'side' of the switch

This will (I hope) leave me with a TV which I can switch between
headphone and speaker modes.

I did this to a small portable TV 15 years ago - I used a 5 terminal
socket ( stereo & it disconnected 2 terminals when a plug was
inserted). As other people have warned, one or more of these contacts
could be at live potential, I didn't check, because I was using an
audio isolating transformer (I think it was from Tandys).
I had to move the loudspeaker connections to the other side of the
transformer (so the cut-out would work correctly). Trouble was the
transformer lost some power, so you had the turn the volume up louder
than before, which caused it to distort if you wanted it loud (but
normal viewing was ok).

Tony.

In article ,
Tony Mudd wrote:
As other people have warned, one or more of these contacts
could be at live potential, I didn't check, because I was using an
audio isolating transformer (I think it was from Tandys).
I had to move the loudspeaker connections to the other side of the
transformer (so the cut-out would work correctly). Trouble was the
transformer lost some power, so you had the turn the volume up louder
than before, which caused it to distort if you wanted it loud (but
normal viewing was ok).

I'd say the ideal cheap transformer would be a telephone line isolating
type if quality isn't that important. A good quality audio isolating
transformer won't be cheap.

--
Is the hardness of the butter proportional to the softness of the bread?*

Dave Plowman London SW 12
RIP Acorn

Hi


several people write:

Modern TVs tend to have a switched mode power supply which
isolates the
chassis from the mains.
If it doesn't then headphone socket is a no-no.

Millions of sets in use today dont have that, and do run with live
chassis. It is not an outdated practice at all.

I just gave away a 10 year old JVC and that had an isolated chassis
as does
my new Sony and the two 5 year old small bedroom sets.
BTW they all had/have headphone sockets too.

right. and millions dont.


How could they run modern electronics without a transformer of some
kind?

TVs have been running transformerless for decades. There is more than
one approach to it.

If there were no external connections, you could use a form of auto
transformer which is marginally cheaper?

you dont need any transformer. There are stacks of silicon based TVs
around running mostly on HT. I have 1 right here. The few bits that
can only be LT dont eat much power, and either HT circuits produce low
voltage at various points to run them, or a low voltage loptf wind is
used to supply them.

Another option is to use a self oscillating lop stage running on HT.
That starts up with no LT and the lop produces the LT needed for the
rest of the set. The LT circuits then pull the lop into sync. Flywheel
sync has been standard for a long old time. There are many approaches.


Millions of sets in use today dont have that, and do run with
live
chassis. It is not an outdated practice at all.

I just gave away a 10 year old JVC and that had an isolated chassis
as
does my new Sony and the two 5 year old small bedroom sets.

I'd agree that all the quality makes I've played with have been fully
isolated.

does that mean all TVs are isolated? Maybe you're overlooking the
consequences of 240v to the head.


BTW they all
had/have headphone sockets too.

Most quality makes do - and also AV connections, so they'd have to
have an
isolated chassis in practice.

those kind normally are, tho again exceptions exist. If 'most' is good
enough for you to apply 240v to the head in 5% of cases, I guess
that's your funeral.


I'd say the ideal cheap transformer would be a telephone line isolating
type if quality isn't that important. A good quality audio isolating
transformer won't be cheap.

I'd say the level of advice in this thread is just plain dangerous.

To connect a headphone to a chassis thats either live, or not live but
not particularly well insulated from live, is a /really/ stupid idea.


Regards, NT