Looking forTV board layout

[Charlie Bress]

I have been chasing an intermittent failure (or a series of failures) in a
1998 Panasonic TV. It is Model CT-27G13W, Chassis #AEDP303.

At first it was loss of raster while maintaining normal audio. I did a
little probing and a magnifying lens search and found a couple of poor,
probably cracked joints, on a pair of heat sinked transistors. I resoldered
those and the set worked for about a week.

Then it failed again. This time it lost vertical sweep and audio. It did
show a single horizontal line that that had enough variation in intensity to
show that video was working. After some more probing (I still have a couple
of old alignment tools) everything is restored again.

Now the big BUT. But tapping the printed circuit board produces a quick
flicker on the picture that says something else is not quite right.

I haven't been doing much with TV since discrete components and tubes went
away so I cannot identify what parts of the board perform what functions. I
can find the obvious like flyback, HOT and tuner.

If some kind soul could scan the board layout and post it to one of the
sites like Flickr it would be a great help. I am not sure if a schematic
will be of great help in this case, but I wouldn't turn it down. If you
prefer to email the scans I will post my real userid so that it can be read
by humans but not by a system that is just harvesting addresses for their
spam.

Charlie

 

[Chance]

I have been chasing an intermittent failure (or a series of failures) in a
1998 Panasonic TV. It is Model CT-27G13W, Chassis #AEDP303.

At first it was loss of raster while maintaining normal audio. I did a
little probing and a magnifying lens search and found a couple of poor,
probably cracked joints, on a pair of heat sinked transistors. I resoldered
those and the set worked for about a week.

Then it failed again. This time it lost vertical sweep and audio. It did
show a single horizontal line that that had enough variation in intensity to
show that video was working. After some more probing (I still have a couple
of old alignment tools) everything is restored again.

Now the big BUT. But tapping the printed circuit board produces a quick
flicker on the picture that says something else is not quite right.

I haven't been doing much with TV since discrete components and tubes went
away so I cannot identify what parts of the board perform what functions. I
can find the obvious like flyback, HOT and tuner.

If some kind soul could scan the board layout and post it to one of the
sites like Flickr it would be a great help. I am not sure if a schematic
will be of great help in this case, but I wouldn't turn it down. If you
prefer to email the scans I will post my real userid so that it can be read
by humans but not by a system that is just harvesting addresses for their
spam.

Charlie

I had a panny of similar vintage with a similar problem. Check the
solider joints on the Vertical output IC, it's located on a heatsink
and has sevral legs. Hope this helps.

Regards,
Chance

 

[AJ]

If you have an ESR Meter it may be a good idea to check the caps in the
deflection and power supply circuits. While doing that check the solder
connection on those devices also.

I have been chasing an intermittent failure (or a series of failures) in a
1998 Panasonic TV. It is Model CT-27G13W, Chassis #AEDP303.

At first it was loss of raster while maintaining normal audio. I did a
little probing and a magnifying lens search and found a couple of poor,
probably cracked joints, on a pair of heat sinked transistors. I
resoldered
those and the set worked for about a week.

Then it failed again. This time it lost vertical sweep and audio. It did
show a single horizontal line that that had enough variation in intensity
to
show that video was working. After some more probing (I still have a
couple
of old alignment tools) everything is restored again.

Now the big BUT. But tapping the printed circuit board produces a quick
flicker on the picture that says something else is not quite right.

I haven't been doing much with TV since discrete components and tubes went
away so I cannot identify what parts of the board perform what functions.
I
can find the obvious like flyback, HOT and tuner.

If some kind soul could scan the board layout and post it to one of the
sites like Flickr it would be a great help. I am not sure if a schematic
will be of great help in this case, but I wouldn't turn it down. If you
prefer to email the scans I will post my real userid so that it can be
read
by humans but not by a system that is just harvesting addresses for their
spam.

Charlie

I had a panny of similar vintage with a similar problem. Check the
solider joints on the Vertical output IC, it's located on a heatsink
and has sevral legs. Hope this helps.

Regards,
Chance

 

[Heinz Schmitz]

I have been chasing an intermittent failure (or a series of failures) in a
1998 Panasonic TV. It is Model CT-27G13W, Chassis #AEDP303.

Did you check how the deflection current gets to the deflection
coils?
I once met a TV where this was done via a very tiny connector plug,
that proved to give bad contact. Cleaning this plug and the pins
resulted in a perfect picture.
As I was told, the previous owner had dumped this device in fear
of too high repair cost.

Regards,
H.