I have a Panasonic TV that is about a decade old that has developed an
intermittent loss of raster. Only once could I get it to respond to a little
judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the
transformer itself and would be more convenient than doing a disconnect at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

The nature of the raster loss leads me to believe that it is NOT the loss of
high voltage, but some other signal. The picture just blinks out sometimes
making a couple of steps toward darkness. The sweeps do not change and the
focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.


Charlie

Only once could I get it to respond to a little
judicious percussive maintenance.

"JPM". Wonderful. I will remember that.

"Meat Plow" wrote in message
...
On Fri, 21 Dec 2007 12:17:32 -0500, Charlie Bress wrote:

I have a Panasonic TV that is about a decade old that has developed an
intermittent loss of raster. Only once could I get it to respond to a
little
judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the
transformer itself and would be more convenient than doing a disconnect
at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

I've seen some that can be removed and some that can't. If yours looks as
if it unplugs and is locked to the fly by a cap then it may be removable.
This is something I can't give a yes or no answer to.

The nature of the raster loss leads me to believe that it is NOT the
loss of high voltage, but some other signal. The picture just blinks
out sometimes making a couple of steps toward darkness. The sweeps do
not change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.



If the HV drops in many cases the picture will shrink as some voltage
supplies are scan derived. (well at least they were back when I repaired
tv) I doubt via your description of the symptoms that the HV is at fault.


I doubt it too. That's why the question I posted. I am looking for the
simplest way to disengage the flyback and HV cable from the CRT

Charlie

"Meat Plow" wrote in message
...
On Fri, 21 Dec 2007 15:28:10 -0500, Charlie Bress wrote:


"Meat Plow" wrote in message
...
On Fri, 21 Dec 2007 12:17:32 -0500, Charlie Bress wrote:

I have a Panasonic TV that is about a decade old that has developed
an
intermittent loss of raster. Only once could I get it to respond to a
little
judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the
transformer itself and would be more convenient than doing a disconnect
at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

I've seen some that can be removed and some that can't. If yours looks
as
if it unplugs and is locked to the fly by a cap then it may be
removable.
This is something I can't give a yes or no answer to.

The nature of the raster loss leads me to believe that it is NOT the
loss of high voltage, but some other signal. The picture just blinks
out sometimes making a couple of steps toward darkness. The sweeps do
not change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.



If the HV drops in many cases the picture will shrink as some voltage
supplies are scan derived. (well at least they were back when I repaired
tv) I doubt via your description of the symptoms that the HV is at
fault.


I doubt it too. That's why the question I posted. I am looking for the
simplest way to disengage the flyback and HV cable from the CRT


What are you hoping to accomplish by removing the HV from the CRT?

Then I can slide the circuit board out (all the other connectors are
straight forward) and inspect for bad solder.

Charlie

"Charlie Bress" wrote in message
. ..

"Meat Plow" wrote in message
...
On Fri, 21 Dec 2007 15:28:10 -0500, Charlie Bress wrote:


"Meat Plow" wrote in message
...
On Fri, 21 Dec 2007 12:17:32 -0500, Charlie Bress wrote:

I have a Panasonic TV that is about a decade old that has developed
an
intermittent loss of raster. Only once could I get it to respond to a
little
judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from
the
transformer itself and would be more convenient than doing a
disconnect
at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

I've seen some that can be removed and some that can't. If yours looks
as
if it unplugs and is locked to the fly by a cap then it may be
removable.
This is something I can't give a yes or no answer to.

The nature of the raster loss leads me to believe that it is NOT the
loss of high voltage, but some other signal. The picture just blinks
out sometimes making a couple of steps toward darkness. The sweeps do
not change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.



If the HV drops in many cases the picture will shrink as some voltage
supplies are scan derived. (well at least they were back when I
repaired
tv) I doubt via your description of the symptoms that the HV is at
fault.


I doubt it too. That's why the question I posted. I am looking for the
simplest way to disengage the flyback and HV cable from the CRT


What are you hoping to accomplish by removing the HV from the CRT?

Then I can slide the circuit board out (all the other connectors are
straight forward) and inspect for bad solder.

Charlie




Taking it out of the picture tube isn't that difficult. Usually you just
have to squeeze them a little and they come out.. If you push the rubber
"suction" cup up you can see how it is in there and how to get it out.. It
is usually rather simple. Oh and of course be sure to discharge it first..
Those things have a nasty bite.

Mike

"Charlie Bress" wrote in message
. ..
I have a Panasonic TV that is about a decade old that has developed an
intermittent loss of raster. Only once could I get it to respond to a
little judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the
transformer itself and would be more convenient than doing a disconnect at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

The nature of the raster loss leads me to believe that it is NOT the loss
of high voltage, but some other signal. The picture just blinks out
sometimes making a couple of steps toward darkness. The sweeps do not
change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.



Some can be removed, it's easier to just disconnect it from the CRT though.
Slip a grounded screwdriver under the anode cup until you touch metal, then
lift up the edge of the rubber cup and disengage the clip from the tube.

Don't over-complicate the situation. Just resolder the vertical output.
Very common on these sets. You may have to replace the IC and a couple of
related caps, but most likely just bad solder connections.

Leonard

"Charlie Bress" wrote in message
. ..
I have a Panasonic TV that is about a decade old that has developed an
intermittent loss of raster. Only once could I get it to respond to a
little judicious percussive maintenance.

It has been along time since I have explored the guts of a TV. I have
experience in board level repairs an want to pull the circuit board to
inspect for poor connections.

The flyback looks as if the high voltage lead can be unplugged from the
transformer itself and would be more convenient than doing a disconnect at
the CRT. Is this feasible? Is the connection at the flyback a simple
straight plug in or is there a locking feature.

The nature of the raster loss leads me to believe that it is NOT the loss
of high voltage, but some other signal. The picture just blinks out
sometimes making a couple of steps toward darkness. The sweeps do not
change and the focus and contrast do not change.

I no longer own a voltmeter with a suitable high voltage probe.


Charlie