I'm wondering if anyone out there can give me some advice about a
recently acquired TV. It's a Panasonic ct-31g30 (32").

When I first powered it up, all was well; all functions worked
properly. After about an hour, the following things occurred:

1. The volume would, at several-minute intervals, briefly blast at full
volume, then resume its previous setting

2. The OSD text became distorted and difficult to read

3. The power button stopped responding.

Once the set cools down, all functionality returns to normal.

I'm guessing that the issue is an ailing EEPROM, but I'd like
confirmation of this (or another guess as to what the problem might
be), and if known, the part number of the suspected chip.

Thanks very much!!
Sean

Pull out the chassis and turn it over ,get out your magnifying
glass ( A Large One )and look for bad solder connections
and resolder them. Reassemble and try...

kip
wrote in message
oups.com...
I'm wondering if anyone out there can give me some advice about a
recently acquired TV. It's a Panasonic ct-31g30 (32").

When I first powered it up, all was well; all functions worked
properly. After about an hour, the following things occurred:

1. The volume would, at several-minute intervals, briefly blast at full
volume, then resume its previous setting

2. The OSD text became distorted and difficult to read

3. The power button stopped responding.

Once the set cools down, all functionality returns to normal.

I'm guessing that the issue is an ailing EEPROM, but I'd like
confirmation of this (or another guess as to what the problem might
be), and if known, the part number of the suspected chip.

Thanks very much!!
Sean

Thanks for the reply Kip.

I had a look at the chassis last night, went over the entire board with
a magnifying glass, and resoldered all pins on the ICs, header pins,
and numerous other areas that looked suspicious. This morning, I ran
the TV for about 45 minutes, and the same behavior occurred again. It
seems as though it consistently takes 45-60 minutes for the problems to
begin to occur, after which they are constant.
One more thing- the TV was left on for a little over an hour yesterday,
and eventually shut down on its own. The power button did nothing at
that point, however I was able to get the set to turn on after
unplugging and plugging it back in.
Any recommendations on what else I could look at?

Thanks again,
Sean

kip wrote:
Pull out the chassis and turn it over ,get out your magnifying
glass ( A Large One )and look for bad solder connections
and resolder them. Reassemble and try...

kip
wrote in message
oups.com...
I'm wondering if anyone out there can give me some advice about a
recently acquired TV. It's a Panasonic ct-31g30 (32").

When I first powered it up, all was well; all functions worked
properly. After about an hour, the following things occurred:

1. The volume would, at several-minute intervals, briefly blast at full
volume, then resume its previous setting

2. The OSD text became distorted and difficult to read

3. The power button stopped responding.

Once the set cools down, all functionality returns to normal.

I'm guessing that the issue is an ailing EEPROM, but I'd like
confirmation of this (or another guess as to what the problem might
be), and if known, the part number of the suspected chip.

Thanks very much!!
Sean

Did you resolder the Horizontal sections ..like Drive Transformer,
Flyback , Drive Transistor etc etc etc ..Not to mention the Relay
regardless what those connections look like.

kip
wrote in message
oups.com...
Thanks for the reply Kip.

I had a look at the chassis last night, went over the entire board with
a magnifying glass, and resoldered all pins on the ICs, header pins,
and numerous other areas that looked suspicious. This morning, I ran
the TV for about 45 minutes, and the same behavior occurred again. It
seems as though it consistently takes 45-60 minutes for the problems to
begin to occur, after which they are constant.
One more thing- the TV was left on for a little over an hour yesterday,
and eventually shut down on its own. The power button did nothing at
that point, however I was able to get the set to turn on after
unplugging and plugging it back in.
Any recommendations on what else I could look at?

Thanks again,
Sean

kip wrote:
Pull out the chassis and turn it over ,get out your magnifying
glass ( A Large One )and look for bad solder connections
and resolder them. Reassemble and try...

kip
wrote in message
oups.com...
I'm wondering if anyone out there can give me some advice about a
recently acquired TV. It's a Panasonic ct-31g30 (32").

When I first powered it up, all was well; all functions worked
properly. After about an hour, the following things occurred:

1. The volume would, at several-minute intervals, briefly blast at full
volume, then resume its previous setting

2. The OSD text became distorted and difficult to read

3. The power button stopped responding.

Once the set cools down, all functionality returns to normal.

I'm guessing that the issue is an ailing EEPROM, but I'd like
confirmation of this (or another guess as to what the problem might
be), and if known, the part number of the suspected chip.

Thanks very much!!
Sean

Yep; all of the above.
Having Googled around a bit, it looks like the voltage regulators on
these sets are problematic. Would a faulty VR cause such erratic
behavior?

Yep ..Is it a STK730XXX..???? or one of its associated components.

kip


wrote in message
oups.com...
Yep; all of the above.
Having Googled around a bit, it looks like the voltage regulators on
these sets are problematic. Would a faulty VR cause such erratic
behavior?

Sorry for my ignorance, as I'm not that familiar with this model, nor
do I have the schematics. I went on Panasonic's parts site and found
the following IC's, each coming up as being a voltage regulator:

AN78M05
AN78L12
AN7809

I didn't see anythign with the prefix that you mentioned. Given how
cheap the parts are, I may just order all three and replace 'em...

I dont think those are your problem ...
Solder all as I suggested first
kip

wrote in message
ups.com...
Sorry for my ignorance, as I'm not that familiar with this model, nor
do I have the schematics. I went on Panasonic's parts site and found
the following IC's, each coming up as being a voltage regulator:

AN78M05
AN78L12
AN7809

I didn't see anythign with the prefix that you mentioned. Given how
cheap the parts are, I may just order all three and replace 'em...

Welp, I soldered everything as you suggested, and replaced the two
voltage regulator ICs, but no success. As I was working on the chassis
last night, I wondered aloud if the problem concerns a component that
is attached to a large heat sink-- the set is fine for 45 minutes to an
hour, then the problems begin.

Any suggestions about what to try next? I've resoldered just about
every point on the chassis (in addition to the spots that you
suggested).

Thanks again,
Sean

What is the part number on this large heat sink ?/

kip
wrote in message
oups.com...
Welp, I soldered everything as you suggested, and replaced the two
voltage regulator ICs, but no success. As I was working on the chassis
last night, I wondered aloud if the problem concerns a component that
is attached to a large heat sink-- the set is fine for 45 minutes to an
hour, then the problems begin.

Any suggestions about what to try next? I've resoldered just about
every point on the chassis (in addition to the spots that you
suggested).

Thanks again,
Sean

You were correct- the regulator is a STK730-020. I just replaced that,
and also found a service bulletin that recommended replacing the HOT
(Q551) and two ceramic caps (both are 2.4K/3W).

So, I replaced everything, and as bad luck would have it, I'm no longer
getting high voltage when I turn on the set- the replay clicks on,
however the tube does not fire up. I'm going to retrace my steps to
night and see what possible could have gone wrong. Arrrgh.

Sean

Sorry- ceramic resistors. Not quite awake yet...
And the upgrade kit for the HOT was TXANV0598SER. All parts are genuine
replaecments.

Sorry- ceramic resistors. Not quite awake yet...
And the upgrade kit for the HOT was TXANV0598SER. All parts are genuine
replaecments.