Sharp 25R-M100 27" CRT, from 2002

Got it last week through work, from someone who broke off the antenna
and tried unsuccesfully to fix it. They already had a better one
anyway, so they were going to junk it.

I fashioned a new coax jack from a connector and a twist tie (for the
center pin) and soldered them in place.
For several days it worked 100% (well, it could use a de-guassing, but
its minor)

Then, all of a sudden, this morning upon turning on, it made the usual
noise and flash of a CRT first turning on, and then immediatly shut off
again.
The power strip it plugs into is shut off at night to save electricity,
so there is no chance that any part was too warm or that it needed to
be reset via disconnecting the power.

I have found that this only happens when the antenna is plugged in
(actually the coax line is from the ReplayTV, which in turn is plugged
into a 12v amplified roof antenna via coax)
If it is on channel "input" then it shuts off if there is a signal at
the composite input.

With coax and composite unplugged, I can go through all channels, I get
the normal blue screen, and I can access the built in menu. Therefor
there is clearly nothing wrong with its capacity to display an image.
But as soon as I plug it in to an incoming signal, it shuts off. I can
generally see an instant of what would be on the screen, and for that
instant it looks normal.

Once it has shut off, it must be unplugged for a few seconds before I
can turn it on again. Once I have done that it will operate from
either the front controls or the remote (assuming I unplug the signal
again).

I have searched the forums, and while there are several entries on
spontaneous shut down, none mention that it only happens if the antenna
(or cable or whatever) is plugged in.

Hopefully that condition will make it much easier to narrow down the
problem.

Thanks

Jacob Aziza wrote:
Sharp 25R-M100 27" CRT, from 2002

Got it last week through work, from someone who broke off the antenna
and tried unsuccesfully to fix it. They already had a better one
anyway, so they were going to junk it.

I fashioned a new coax jack from a connector and a twist tie (for the
center pin) and soldered them in place.
For several days it worked 100% (well, it could use a de-guassing, but
its minor)

Then, all of a sudden, this morning upon turning on, it made the usual
noise and flash of a CRT first turning on, and then immediatly shut off
again.
The power strip it plugs into is shut off at night to save electricity,
so there is no chance that any part was too warm or that it needed to
be reset via disconnecting the power.

I have found that this only happens when the antenna is plugged in
(actually the coax line is from the ReplayTV, which in turn is plugged
into a 12v amplified roof antenna via coax)
If it is on channel "input" then it shuts off if there is a signal at
the composite input.

With coax and composite unplugged, I can go through all channels, I get
the normal blue screen, and I can access the built in menu. Therefor
there is clearly nothing wrong with its capacity to display an image.
But as soon as I plug it in to an incoming signal, it shuts off. I can
generally see an instant of what would be on the screen, and for that
instant it looks normal.

Once it has shut off, it must be unplugged for a few seconds before I
can turn it on again. Once I have done that it will operate from
either the front controls or the remote (assuming I unplug the signal
again).

I have searched the forums, and while there are several entries on
spontaneous shut down, none mention that it only happens if the antenna
(or cable or whatever) is plugged in.

Hopefully that condition will make it much easier to narrow down the
problem.

Hi...

Fashioned a new coax jack from a connector and a twist tie for the
center pin? Don't understand what the twist tie does, but I'm scared

Start by getting ahold of a proper connector, and installing it
properly.

Then try it again.

Take care.

Ken

the connector is a coax male-male adaptor, for connecting two cables to
each other.
It was built assuming that each cable would have the little wire in the
middle. The TV side of it was broken off with the original connector.
The twist tie (with the paper stripped off) just serves as a thin piece
of metal to go in the middle. I don't think that is the problem
(wouldn't make any sense.) As to installing it properly, how would you
connect the coax jack except with solder? It needs to be a secure
electrical connection. If I had something designed for this purpose,
would it not be essentially the exact same thing, (except for a lot of
money), and wouldn't it still be soldered in place?

I thought of the possibility that I had shorted the coax by having a
bit of solder crossed between the two, but in that case, why would the
same thing happen from the RCA composite input even with the coax
unplugged? The RCA jacks aren't routed through the coax, they are
entirely different types of signal.

Any particular reason why building the part would cause this problem
but buying it wouldn't?

Ken Weitzel wrote:

Hi...

Fashioned a new coax jack from a connector and a twist tie for the
center pin? Don't understand what the twist tie does, but I'm scared

Start by getting ahold of a proper connector, and installing it
properly.

Then try it again.

Take care.

Ken

"Jacob Aziza" wrote in message
ups.com...

I have found that this only happens when the antenna is plugged in
(actually the coax line is from the ReplayTV, which in turn is plugged
into a 12v amplified roof antenna via coax)

Sounds like you are grounding the set out - this is very bad and possibly
dangerous.

Could you explain what this means, what it would cause, and how I can
fix it?

Why would it happen only when connected to a video source?

The same exact wires plugged into my other TV set works 100%, so they
are not grounded. But if it were grounded internally, it shouldn't
matter if a video source is plugged in or not. Right?

Homer J Simpson wrote:
"Jacob Aziza" wrote in message
ups.com...

I have found that this only happens when the antenna is plugged in
(actually the coax line is from the ReplayTV, which in turn is plugged
into a 12v amplified roof antenna via coax)

Sounds like you are grounding the set out - this is very bad and possibly
dangerous.

"Jacob Aziza" wrote in message
oups.com...

Could you explain what this means, what it would cause, and how I can
fix it?

It may mean that you have a live chassis (which is strange these days) and
that you have bypassed the safety system built into the set, which is very
dangerous.

Why would it happen only when connected to a video source?

Because that's when you are grounding the antenna input.

The same exact wires plugged into my other TV set works 100%, so they
are not grounded. But if it were grounded internally, it shouldn't
matter if a video source is plugged in or not. Right?

Right. Something is wrong.

Check for voltage between the antenna port and your antenna wire with a
voltmeter. Also check between your antenna and earth for voltage and the
antenna port and earth.

This should give you some idea where to start looking for problems.

- Mike

"Homer J Simpson" wrote in message
news:Rtu7h.15170$C94.1683@edtnps82...

"Jacob Aziza" wrote in message
oups.com...

Could you explain what this means, what it would cause, and how I can
fix it?

It may mean that you have a live chassis (which is strange these days) and
that you have bypassed the safety system built into the set, which is very
dangerous.

Why would it happen only when connected to a video source?

Because that's when you are grounding the antenna input.

The same exact wires plugged into my other TV set works 100%, so they
are not grounded. But if it were grounded internally, it shouldn't
matter if a video source is plugged in or not. Right?

Right. Something is wrong.

Thank you for your responce.
Should there be voltage between any of those places?
When you say "earth" you mean the ground wire at the outlet, right?


Michael Kennedy wrote:
Check for voltage between the antenna port and your antenna wire with a
voltmeter. Also check between your antenna and earth for voltage and the
antenna port and earth.

This should give you some idea where to start looking for problems.

- Mike

"Homer J Simpson" wrote in message
news:Rtu7h.15170$C94.1683@edtnps82...

"Jacob Aziza" wrote in message
oups.com...

Could you explain what this means, what it would cause, and how I can
fix it?

It may mean that you have a live chassis (which is strange these days) and
that you have bypassed the safety system built into the set, which is very
dangerous.

Why would it happen only when connected to a video source?

Because that's when you are grounding the antenna input.

The same exact wires plugged into my other TV set works 100%, so they
are not grounded. But if it were grounded internally, it shouldn't
matter if a video source is plugged in or not. Right?

Right. Something is wrong.

"Jacob Aziza" wrote in message
ups.com...

Thank you for your responce.
Should there be voltage between any of those places?
When you say "earth" you mean the ground wire at the outlet, right?

'Earth' is British for 'Ground'.

Jacob Aziza wrote:

Could you explain what this means, what it would cause, and how I can
fix it?

Why would it happen only when connected to a video source?

The same exact wires plugged into my other TV set works 100%, so they
are not grounded. But if it were grounded internally, it shouldn't
matter if a video source is plugged in or not. Right?

Homer J Simpson wrote:

"Jacob Aziza" wrote in message
roups.com...


I have found that this only happens when the antenna is plugged in
(actually the coax line is from the ReplayTV, which in turn is plugged
into a 12v amplified roof antenna via coax)

Sounds like you are grounding the set out - this is very bad and possibly
dangerous.


try this unplug your coax and turn the set on, then touch only the
shield of your coax connector to the outside of the ant coax, if you
see a spark or the set turns off then you indeed do have a ground loop
problem...and if so check your ace plug to see if someone might have cut
off the ears of the plug, meaning the wide termianl of the plug if so
them look closely and replug the plug into a wall outlet making sue the
wide term goes into the wide side of the outlet