Ballast Repair Kit for Panasonic PT-40LC12 and PT-45LC12

This thread is basically a continuation of http://www.avsforum.com/avs-vb/showthread.php?t=958640

Based on brogers' thread, I ordered the same ballast repair kit intented for the Panasonic PT-xxLC13 series and applied it to the Panasonic PT-xxLC12 series.

Please note that the following information is provided at your own risk. What worked for me may not work for you. This procedure involves soldering and electronic experience!

Apparently, after many ballast and bulb failures, Panasonic put out a kit of components marketed as the "Panasonic Ballast Repair Kit", #LSUC0022. This kit contains 1 transistor, 1 resistor, 2 diodes, 1 capacitor, and 1 fuse. The purpose of this kit was to replace probable defective components on the Ballast circuit board.

There are two versions of this repair kit. The older version, LSQL1865, contains the original parts supplied to the PT-xxLC13 family. The newer version, LSQL1865-1, contains newer equivalent parts that were supplied to the newer PT-xxLC14 and later families of Panasonic TVs. If you have a choice, I would get the newer version, as there may have been improvements to the componenents.

I received the older version (not by choice), whereas brogers received the newer version.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12a.JPG

The kit matchups are listed here, and where each component gets installed:


LSQL1865 LSQL1865-1 PT-50LC13 PT-40LC12 Description

1. B2ZAZ0000020 B2ZAZ0000020 D1315 D1317 Diode
2. D1FZ100E0001 D1F5100E0002 R1305 R1703 Resistor
3. MA2Q73600L MA2Q73600L D1301 D1701 Diode
4. LSSF0013B50T K5D502BNA005 F1301 F1701 Fuse
5. B1DEGQ000011 B1DEGQ000044 Q1306-9 Q1302-6 Transistor
6. F0CAH104A001 F0CAH104A001 C1330 C1314 Capacitor


The PT-40LC12 combines the LCD power supply (1700 series) with the ballast (1300 series) on the same circuit board. Therefore, the component locations are different on the PT-40LC12 than what is mentioned in the kit for the PT-50LC13.

Also note that this kit contains only one transistor, whereas the PT-40LC12 and PT-50LC13 has at least 4 transistors. It might be worthwhile to order additional transistors and replace them as a set.

Also to be noted, the ballast on the PT-40LC12 is buried underneath the bulb housing, unlike the PT-50LC13 which is located right at the rear of the set. Therefore, the PT-40LC12 needs major unassembly to get to the ballast.

Here are the steps needed to get to the ballast:

1) Unplug the TV you are going to work on.
2) Remove the TV rear cover by removing 20 screws.
3) Remove the AV flip-down front door.
4) Remove the front left and right speaker covers.
5) Remove the front center panel by removing 4 screws, and unplugging connector P6303.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12b.JPG

6) Remove the lamp cover door.
7) Remove the lamp housing (that contains the bulb).
8) Open the front base panel by removing 16 screws. Remove the ground strap screw so that the base front panel can lay down.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12c.JPG

9) Unplug connectors P1010 and P4504 from the main circuit board.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12d.JPG

10) Remove 4 screws that attach grounding straps and grounding plates to the ballast.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12e.JPG

11) At the rear of the set, remove the duct fan by removing 4 screws. Unplug connector P804 from the main circuit board.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12f.JPG

12) Remove the Audio Power unit by unplugging connector P1101 and removing 2 mounting screws.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12g.JPG

13) Remove the 10 screws as shown. Basically, you are removing 2 screws to release the lamp socket on the lamp housing. Then remove 2 screws to the temperature fuse on the lamp housing. Remove 1 screw to the ground plate and ground wire on the lamp housing. Remove 1 screw to the ground wire on the ballast. Remove 2 screws that hold the ground plate to the ballast. Unplug connector P1905 from the LCD Main circuit board. Finally, remove 2 mounting screws that hold the ballast cage to the base, and lift the ballast cage out of the set. See diagram.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12h.JPG

14) Pry off the cover to the ballast cage. Unplug connector P1703 and fully remove the cover.

http://www.elirion.net/~tomwil/Panasonic/PT40LC12i.JPG

15) Remove the ballast circuit board from the cage by removing the 3 mounting screws and lifting the circuit board from the posts.

16) Locate each component as shown. Each component name is clearly written on the circuit board. Replace the components with the new componenents from the kit. Note polarity especially with the diodes. This procedure involves soldering and electronic experience!

http://www.elirion.net/~tomwil/Panasonic/PT40LC12j.JPG

http://www.elirion.net/~tomwil/Panasonic/PT40LC12k.JPG

17) Reassemble everything in reverse order. Take your time, and pay attention to reconnecting all the connectors and grounding plates, straps and wires.

If you notice anything missing or inaccurate with these instructions, please let me know. Sorry for the watermark on the pictures; they are to help prevent the sale or misuse of these instructions. Thanks to brogers for initiating this process!

Thank you VERY much for re-posting this

Greetings. First of all, many thanks for the excellent assistance offered in this thread. It savedme much panic and hair pulling.
I have a PT-45LC12 TV, and yes, I hate the low life of the bulb. Yesterday I turned on my TV to find flashing green light, no picture. Upon investigation on the web, I found your site (among others) talking about the thermal fuse and the ballast repair. I popped the back of the TV off, checked the obviously placed thermal fuse with my multi-meter, sure enough, no continuity. Snipped it off, temporarily crimped the wires together, TV works. My local electronics store has a similar thermal fuse (117 c instead of 115c) which I will pick up tonight on the way home and crimp into place.
Questions.
1. Any evidence out there that a blown thermal fuse is an indication of further problems? I deal with thermal fuses in my work, so I know sometimes they just die, for no good reason, just "your time is up"

2. Is there any compelling reason to go through the hassle (and possible danger of damaging components) to replace the components in the LSUC0022 repair kit (best price I have found is tristatemodule $15.89 plus shipping, minimum shipping $7.95) Will replacing the components (specifically the capacitor,which I read has a different value than the one stock in the board) possibly avoid future problems or extend the life of my bulb?

Thank you again for all the great helps, photos, instructions and hand holding for these problems. (I wonder why they didn't include a thermal fuse in the ballast repair kit)

1. Any evidence out there that a blown thermal fuse is an indication of further problems? I deal with thermal fuses in my work, so I know sometimes they just die, for no good reason, just "your time is up".

It probably just blew from age and usage. However, if the new one you install blows, then it might need more investigation.

2. Is there any compelling reason to go through the hassle (and possible danger of damaging components) to replace the components in the LSUC0022 repair kit? Will replacing the components (specifically the capacitor,which I read has a different value than the one stock in the board) possibly avoid future problems or extend the life of my bulb?

I believe the repair kit was offered to solve the "bulb not lighting" problem. Whether it protects or extends the life of the bulb is not really known.

As far as the capacitor, according to the Panasonic parts list the replacement capacitor in the kit is the same value, but probably bigger and beefier.

If your set works normally after the thermal fuse replacement, it would probably not be worth the risk of installing the ballast kit.

d1701 is not marked on the old diode or on the board for the relay. I know a diode is needed to keep current going to ground when the field breaks down so which way is south? I should'a measured it first before jumpimg in. I'm trying to get it running by Christmas. in ref to gnd the line goes where? North
Edit
OK, made me look. service manual is usless here. "unit replacement" I see gnd on one side only. I am assuming the line is not on gnd.

d1701 is not marked on the old diode or on the board for the relay.

Reference here (http://www.avsforum.com/avs-vb/showthread.php?p=15372540#post15372540).

I just inherited a PT-40LC12 after a friend gave up on it. He replaced the bulb a couple of times and then it started flashing codes to him.

When the unit is first turned on, the green light flashes a few times and then the warning message is displayed that the lamp has to be replaced. This is shown for about 20 seconds, and then the lamp shuts down. The TEMP lamp flashes 4 times every 5 seconds or so. I've tried resetting the lamp timer, but the lamp shuts down before the timer is reset. Looking at this and other forums, I tried replacing the thermistor located on top of the lamp cage, but still get the same response.

Any suggestions?

The TEMP lamp flashes 4 times every 5 seconds.

The service manual indicates that the code means the air filter needs cleaning, or replacement.

The service manual indicates that the code means the air filter needs cleaning, or replacement.
The air filter looks nearly brand new. Is there a sensor that might be bad?

The air filter looks nearly brand new. Is there a sensor that might be bad?

You seem to be experiencing the same problem as this post (http://www.avsforum.com/avs-vb/showthread.php?p=14447605#post14447605).

His solution was to unplug and replug the connector to the lamp thermistor (the small circuit board mounted above the lamp cage).

The purpose of the lamp thermistor is to detect overheating of the bulb. If the thermistor is bad, it can be replaced ($4 part #D4CE31330001).

The part you originally replaced was the temperature fuse, which is different from the thermistor.

Tom,

Thanks for the suggestion. I had replaced the fuse instead of the thermistor. I just replaced the thermistor, but still don't have a working unit. The behavior has changed slightly, however. Now, after the lamp turns off, I get 4 quick flashes of the temp light, then a few seconds later one long flash. That cycle repeats. Any ideas?

Thanks again!

Paul

Paul -

You have two errors going. I am going to give you what is mentioned in the service manual.

Temp LED flashes once every 5 seconds

Cause: detects open or short of the Temperature Sensor (R2911) on Front Thermistor C.B.A.

Resolution: Replace the Temperature Sensor (R2911) on Front Thermistor C.B.A. If still No Good, replace the Projection Unit. Note: The Projection Unit includes LCD Main C.B.A.

Temp LED flashes 4 times every 5 seconds

Cause: detects the temperature attached near the Lamp by the Temperature Sensor (R2901) on Lamp Thermistor C.B.A., then indicates the error when the temperature becomes more than 60 C (140 F).

Possible causes:

1. Clogged air filter.
2. Blocked air intake.
3. The surrounding temperature of the place of use may be too high.

Resolution: Cleaning the Air Filter.


The above is what is mentioned in the service manual.

The least expensive repair is the check or replace the front fan thermistor, ~$3.50, #D4CA35030002. The projection unit is very expensive.

You might also want to check the filter and the way it seals, to insure no blockage. Also, check both the front fan and lamp fan, and be sure both are spinning at a reasonable rate.

Hope this helps!

I have a PT45LC12 and replaced the bulb (not the entire lamp assembly) in September with an Osram bulb I got from River Valley Electronics after the original bulb blew (worked for 4-5 years). Recently I've started to get the problem where the picture will come on for 10-30seconds and then the lamp shuts off, the fan keeps running, and the lamp light flashing 4 times, pause, flashes 4 times which keeps repeating until I hit the power button again.

I've done quite a bit of searching on the net for this problem and have found people mentioning it but no indication of a fix. A post on another forum gives this info (which comes from the repair manual):

"That is the blink code for the lamp ballast. Here is the more complicated explanation from the service manual.

IC2301(pin11) detects the error of LCD Power C.B.A. and Lamp,
then indicates the error when an inner malfunction of LCD Power
C.B.A. occurs, the Lamp voltage becomes more than 130V or
less than 30V, Lamp current becomes more than 5A, or the Lamp is blown."

I don't exactly know what the above means...So my (uneducated) thoughts:

1)The lamp itself? There's alot of discussion on the pros and cons of OEM/non-Panasonic bulbs vs the entire lamp assembly direct from Panasonic so this could be the problem. I also assume that a bad bulb could be the cause of the error that seems to be propagating to some board somewhere. I'm just wary as a)someone in one of the other threads I found mentioned that putting in a new bulb did not fix this problem, b)the lamp itself does work for about 30secs until the TV decides to shut it off, and mainly c)shelling out 300bucks on the chance it fixes my problem isn't that desirable while there are cheaper methods to try.

2)Alot of people mention that similar problems (but not this exact one) have been fixed by replacing the thermal fuse or the thermistor. Could a bad/old fuse or thermistor make the system think there is a problem with voltage or amperage? After opening up the back of the TV and finding these parts, this definitely looks like something I can do so I'll be trying this as soon as the parts come in.

3)Using the ballast repair kit detailed in this post? This also seems cheap enough to try but seems to be well past my skill set to attempt. This one may take a while to attempt while I round up a skilled electronics guy. As this TV is on the old side, I don't want to take it to a repair shop and get charged hundreds of dollars to fix it when this post makes it sound like a electronics enthusiast could do the work in an hour or so...


So, I guess I'm posting to see if anyone on these forums has any other suggestions for things I could try?

Or if someone checking these forums has found a fix for my problem?

Jwburt -

Never had your problem.

But you seem to have figured out most of the possibilities.

It is probably your lamp that is causing the problem. For some reason your TV circuitry is detecting abnormal voltages with your bulb; it's probably drawing too much current to keep lit. If it was temperature related, the temp light usually flashes instead.

I don't think the temperature fuse or the thermistors are causing your problem, but they are inexpensive to replace.

That leaves pretty much the lamp or the power supply (ballast).

You could try reseating the connections between the thermistors, lamp, power board, and the main board. Maybe a high-resistant contact is causing the problem.

Not sure if the ballast repair kit would help your problem. Usually the kit is used to solve a non-starting lamp, although other benefits are not known at this time.

The true Panasonic lamps appear to solve most problems. The other "OEM" lamps seem to be a crap-shoot ... maybe they work, maybe they don't. And, those "OEM" lamps seem to have a very short lifespan if they do work initially.

Please let us know how you solve this. Thanks!

Hello,

I have read through nearly all of this forum starting with Broggers original post. But, I have not seen my specific set of symptoms.

The television will not turn on at all, which seems to indicate the ballast repair is needed. In which case the first diagrams on this forum for the 45LC12 would be great, thank you!

However, it is not just throwing the lamp error light. The specific sequence is:

1) Upon plugging it in the power led goes from green, to two yellow flashes, to red.

2) The temp led flashes

3) after a few seconds of gap, the Lamp LED lights and stays lite for 5 seconds

4) the power led flashes red again

5) then the temp led flashes once followed by a four second gap then the lamp led for 5secs

6) the total cycle takes 15secs

Does this mean it is both the front Thermoster and ballast need to be replaced? Or is this beyond fatal?

Thanks! :eek: :confused: :eek:

I have a PT-40LC12. This morning I tried to turn it on I can hear it powering up but after awhile of the green light flashing it turns to flashing red then powers down. What can this be?:confused:

I have a PT-40LC12. This morning I tried to turn it on I can hear it powering up but after awhile of the green light flashing it turns to flashing red then powers down. What can this be?:confused:

Usually it is either the bulb or the ballast.

There is a chart of the blinking lights here (http://www.avsforum.com/avs-vb/attachment.php?attachmentid=141714&d=1241461185).

Hello,

My in-laws have a Panasonic PT-40LC12. And im trying to get to the bottom of why its not working! I tried powering it on yesterday and the GREEN POWER LED light keeps on flashing and nothing would display on the screen. So i went to go look at the service manual, they said to check the to see if the Rear fan was on. And the fan was, so they directed me to the temp. fuse. But after reading this Thread im kinda stump on what to do now.

Please let me know on what i need to do???????

Anyone please????

There have been many posts here about this model. Could be lamp or could be Ballast. Lamp is TY-LA1000 for about $100. Ballast is $600 - $300 parts/$300 Labor. or a You Fit it kit #LSUC0022 for about $20 which you would be soldering 6 diode/resisters to circuit board.

I have a PT-60LC13 for 5 years and have replaced 3-4 bulbs. Just replaced the bulb two weeks ago and then went out again. 140 Green blinking LED lights - then 5 Red - 1 Yellow, means light and ballast bad. Thread above has
service manual page explaining the blinking lights. Good Luck.

I have the PT-45LC12 Panasonic. I was watching the unit just shutoff. Didn't make the dreaded pop from the bulb blowing. It just shut off. I looked at the bulb it seems to be fine. Now the Green light just flashes and thats it. I don't hear the fans or anything... Please help I would hate to throw this tv away if it's something simple.
Thanks

We just replaced the bulb in our PT-45LC12 and now it takes up to 4 minutes for the TV to turn on... we get a blue screen when turned on and then the tv picture finally turns on... any ideas of why this may be happening?

Hello,

My in-laws have a Panasonic PT-40LC12. And im trying to get to the bottom of why its not working! I tried powering it on yesterday and the GREEN POWER LED light keeps on flashing and nothing would display on the screen. So i went to go look at the service manual, they said to check the to see if the Rear fan was on. And the fan was, so they directed me to the temp. fuse. But after reading this Thread im kinda stump on what to do now.

Please let me know on what i need to do???????

Exact same issue with the PT-45LC12 with one side effect... the front fan on the right if looking at the front of the TV doesn't spin.

Where can I throw away this tv? I bought it used from a friend for 300 bucks... there's no way I'm paying 600 bucks for a part, the lamp was the most I was going to spend, but if I can get away with just replacing the fan cool, but if I get it replaced and it still doesn't work. bah.

I have a PT45LC12 and replaced the bulb (not the entire lamp assembly) in September with an Osram bulb I got from River Valley Electronics after the original bulb blew (worked for 4-5 years). Recently I've started to get the problem where the picture will come on for 10-30seconds and then the lamp shuts off, the fan keeps running, and the lamp light flashing 4 times, pause, flashes 4 times which keeps repeating until I hit the power button again.

I've done quite a bit of searching on the net for this problem and have found people mentioning it but no indication of a fix. A post on another forum gives this info (which comes from the repair manual):

"That is the blink code for the lamp ballast. Here is the more complicated explanation from the service manual.

IC2301(pin11) detects the error of LCD Power C.B.A. and Lamp,
then indicates the error when an inner malfunction of LCD Power
C.B.A. occurs, the Lamp voltage becomes more than 130V or
less than 30V, Lamp current becomes more than 5A, or the Lamp is blown."

I don't exactly know what the above means...So my (uneducated) thoughts:

1)The lamp itself? There's alot of discussion on the pros and cons of OEM/non-Panasonic bulbs vs the entire lamp assembly direct from Panasonic so this could be the problem. I also assume that a bad bulb could be the cause of the error that seems to be propagating to some board somewhere. I'm just wary as a)someone in one of the other threads I found mentioned that putting in a new bulb did not fix this problem, b)the lamp itself does work for about 30secs until the TV decides to shut it off, and mainly c)shelling out 300bucks on the chance it fixes my problem isn't that desirable while there are cheaper methods to try.

2)Alot of people mention that similar problems (but not this exact one) have been fixed by replacing the thermal fuse or the thermistor. Could a bad/old fuse or thermistor make the system think there is a problem with voltage or amperage? After opening up the back of the TV and finding these parts, this definitely looks like something I can do so I'll be trying this as soon as the parts come in.

3)Using the ballast repair kit detailed in this post? This also seems cheap enough to try but seems to be well past my skill set to attempt. This one may take a while to attempt while I round up a skilled electronics guy. As this TV is on the old side, I don't want to take it to a repair shop and get charged hundreds of dollars to fix it when this post makes it sound like a electronics enthusiast could do the work in an hour or so...


So, I guess I'm posting to see if anyone on these forums has any other suggestions for things I could try?

Or if someone checking these forums has found a fix for my problem?


I am having the same problem with my PT40LC12, did you find a solution?

What a great forum; this is exactly the type of sharing that makes the web such a wonderful tool.

I have the same issue: lamp comes on, the green power goes red and blinking constantly, and the red lamp led blinks four times.

After reviewing this post, I dug into the unit with some hesitation but determined, thinking I would tear it down and do the ballast fix. I got to the point where I was pulling the two screws for the lamp socket in step 13 and discovered the lamp socket was broken. Basically, the socket has "ears" that these two screws use to secure it to the chassis. Well, one of my ears was broken.

The question is this: if that socket was not pushed on securely, could it mimic the symptoms of the ballast problem? I am tempted to put it back together now that I have fixed the socket ( a little super glue did the trick) before ordering the kit, to see if perhaps a minimal connection was the fault.

ANY ADVICE???

Thanks for the help!!

i have a pt-40lc12 and i just replaced the bulb and it worked for about four months and now it turns on for just 30 seconds then it turns off and the temp ligth flashs 4 times every few seconds can any one help me with this problem

Hey everyone,

I have a PT45LC12 that is also acting weird. It turns on fine but it turns it self off for a minute or two (while the green indicator is flashing). After a minute or two it goes back on as if nothing happened. Sometimes it never does this, most of the time it does it twice in a matter of 5 minutes thats it and sometimes it does it 3, 4 or even 5 times. Image is good, sound is good but this is definitely driving us crazy.

I replaced the lamp about 8 weeks ago and it was fine until about 3 weeks.

Any suggestions?

Thanks!

W

Check the thermal cutoff if you read towards the middle of this thread you will find the "short out Test". These sets are very easy to fix and parts are available. The only problem I could not fix was the green square problem which was a firmware issue fixed by a Panasonic rep.

Found a copy of the Panasonic PT-40LC12 and PT-45LC12 Service Manual here (http://www.my.electronicshelponline.com/uploads/PT40LC12.zip).

LSUA0041 Cover Switch Defeat Cable Note:
A replacement part (LSJA0476), which is shorted, can be used for this
service tool.

LSUA0003 Thermistor 1 Defeat Cable Note:
Replacement part (LSJA0477), to which a 68k ohm resistor has been
attached, can be used for this service tool.

LSUA0013 Thermistor 2 Defeat Cable Note:
Replacement part (LSJA0533, LSJA0478), to which a 47k ohm
resistor has been attached, can be used for this service tool.

you cannot just short the thermister on those sets.
cheers.

I recently received a PT-40LC12 from a friend who was moving. 3 weeks after, I think the lamp has gone out. I power it on and just get the same blinking light. I asked him about it and he told me he had the bulb replaced about 2 years ago. From what I have read it sounds like it was due. I have purchased a replacement bulb but can find NO instructions on how to remove the bulb and housing from the TV. Can anyone help by directing me to where I can find a decent take a part guide? I have found the service manual, but it is either incomplete or simply doesn't cover bulb replacement (which seems unlikely.) PLEASE HELP!

I recently received a PT-40LC12 from a friend who was moving. 3 weeks after, I think the lamp has gone out. I power it on and just get the same blinking light. I asked him about it and he told me he had the bulb replaced about 2 years ago. From what I have read it sounds like it was due. I have purchased a replacement bulb but can find NO instructions on how to remove the bulb and housing from the TV. Can anyone help by directing me to where I can find a decent take a part guide? I have found the service manual, but it is either incomplete or simply doesn't cover bulb replacement (which seems unlikely.) PLEASE HELP!

That Service Manual has a really goofy structure. Look through all the files in the Service Manual folders, and find a little file called navigator.html. Open it, and it will open a browser page which is a guide to the SM and must be used to open any other file. Bulb replacement is included, I believe in a section called Service Notes.

Can find NO instructions on how to remove the bulb and housing from the TV. Can anyone help by directing me to where I can find a decent take a part guide? I have found the service manual, but it is either incomplete or simply doesn't cover bulb replacement (which seems unlikely.)

As ChuckF said, if you use the navigator, click on 1.4.4 Service Notes, and open the svcnote.pdf file. Lamp replacement procedure with pictures is located on page 12.

Or, you can use Panasonic's instructions for the TY-LA1500 (http://service.us.panasonic.com/OPERMANPDF/TYLA1500.PDF).

If you want to replace the bulb only and use the existing cage, instructions here (http://www.fixyourdlp.com/guides/panasonic/ty-la1500.php).

My Panasonic PT-45LC12 turns on but after a minute the message pops up for me to change the air filter. I replaced the filter but the same message keeps poping up and then shuts down the unit after 1 munute and the temperature light starts flashing red. What else can I do to fix this problem? Please help!

what filter did you change? there on the lcd unit.
Cheers

Well here is what I have now that I've replaced the thermal fuse, Temp light flashes 3 times every 5 seconds. I looked it up and I guess I need the P2901 Thermistor right? I want to get this TV working so If I replace the P2901 does anyone think this thing will work? I do not hear anything out of the ballast but all fans are working. Anyone with some suggestions?


EDIT: Well I do not have the flashing temp light any more but back to were I started, no ballast clicking and trying to light the lamp. On button is flashing green for 100 some times then red till it shuts down. Is this a lamp problem or has my ballast crapped out???????

I have the same problem. Any fixes for this? Appreciate if any one found a fix for this:-)

I have a PT45LC12 and replaced the bulb (not the entire lamp assembly) in September with an Osram bulb I got from River Valley Electronics after the original bulb blew (worked for 4-5 years). Recently I've started to get the problem where the picture will come on for 10-30seconds and then the lamp shuts off, the fan keeps running, and the lamp light flashing 4 times, pause, flashes 4 times which keeps repeating until I hit the power button again.

I've done quite a bit of searching on the net for this problem and have found people mentioning it but no indication of a fix. A post on another forum gives this info (which comes from the repair manual):

"That is the blink code for the lamp ballast. Here is the more complicated explanation from the service manual.

IC2301(pin11) detects the error of LCD Power C.B.A. and Lamp,
then indicates the error when an inner malfunction of LCD Power
C.B.A. occurs, the Lamp voltage becomes more than 130V or
less than 30V, Lamp current becomes more than 5A, or the Lamp is blown."

I don't exactly know what the above means...So my (uneducated) thoughts:

1)The lamp itself? There's alot of discussion on the pros and cons of OEM/non-Panasonic bulbs vs the entire lamp assembly direct from Panasonic so this could be the problem. I also assume that a bad bulb could be the cause of the error that seems to be propagating to some board somewhere. I'm just wary as a)someone in one of the other threads I found mentioned that putting in a new bulb did not fix this problem, b)the lamp itself does work for about 30secs until the TV decides to shut it off, and mainly c)shelling out 300bucks on the chance it fixes my problem isn't that desirable while there are cheaper methods to try.

2)Alot of people mention that similar problems (but not this exact one) have been fixed by replacing the thermal fuse or the thermistor. Could a bad/old fuse or thermistor make the system think there is a problem with voltage or amperage? After opening up the back of the TV and finding these parts, this definitely looks like something I can do so I'll be trying this as soon as the parts come in.

3)Using the ballast repair kit detailed in this post? This also seems cheap enough to try but seems to be well past my skill set to attempt. This one may take a while to attempt while I round up a skilled electronics guy. As this TV is on the old side, I don't want to take it to a repair shop and get charged hundreds of dollars to fix it when this post makes it sound like a electronics enthusiast could do the work in an hour or so...


So, I guess I'm posting to see if anyone on these forums has any other suggestions for things I could try?

Or if someone checking these forums has found a fix for my problem?
I have a PT45LC12 and replaced the bulb (not the entire lamp assembly) in September with an Osram bulb I got from River Valley Electronics after the original bulb blew (worked for 4-5 years). Recently I've started to get the problem where the picture will come on for 10-30seconds and then the lamp shuts off, the fan keeps running, and the lamp light flashing 4 times, pause, flashes 4 times which keeps repeating until I hit the power button again.

I've done quite a bit of searching on the net for this problem and have found people mentioning it but no indication of a fix. A post on another forum gives this info (which comes from the repair manual):

"That is the blink code for the lamp ballast. Here is the more complicated explanation from the service manual.

IC2301(pin11) detects the error of LCD Power C.B.A. and Lamp,
then indicates the error when an inner malfunction of LCD Power
C.B.A. occurs, the Lamp voltage becomes more than 130V or
less than 30V, Lamp current becomes more than 5A, or the Lamp is blown."

I don't exactly know what the above means...So my (uneducated) thoughts:

1)The lamp itself? There's alot of discussion on the pros and cons of OEM/non-Panasonic bulbs vs the entire lamp assembly direct from Panasonic so this could be the problem. I also assume that a bad bulb could be the cause of the error that seems to be propagating to some board somewhere. I'm just wary as a)someone in one of the other threads I found mentioned that putting in a new bulb did not fix this problem, b)the lamp itself does work for about 30secs until the TV decides to shut it off, and mainly c)shelling out 300bucks on the chance it fixes my problem isn't that desirable while there are cheaper methods to try.

2)Alot of people mention that similar problems (but not this exact one) have been fixed by replacing the thermal fuse or the thermistor. Could a bad/old fuse or thermistor make the system think there is a problem with voltage or amperage? After opening up the back of the TV and finding these parts, this definitely looks like something I can do so I'll be trying this as soon as the parts come in.

3)Using the ballast repair kit detailed in this post? This also seems cheap enough to try but seems to be well past my skill set to attempt. This one may take a while to attempt while I round up a skilled electronics guy. As this TV is on the old side, I don't want to take it to a repair shop and get charged hundreds of dollars to fix it when this post makes it sound like a electronics enthusiast could do the work in an hour or so...


So, I guess I'm posting to see if anyone on these forums has any other suggestions for things I could try?

Or if someone checking these forums has found a fix for my problem?

I'm having the same *exact* issue (including my lack of electronics fluency :) ) with my pt45lc12 as described by Jwburt, repeated by several others (bassman69504, mattsmark). The only datapoint I have to add to this is that my lamp is an OEM but has been working for almost 2 years now without incident.

Maybe the only other piece of information I can add is that I neglected to clean the air filter as rigorously as I ought, but frankly I've had the same pattern throughout the life of my TV (since 2002) and never had *this* issue before.

Anyone have an update on what to look for? I don't want to buy a new lamp if it's not the problem.

I'm having the same *exact* issue (including my lack of electronics fluency :) ) with my pt45lc12 as described by Jwburt, repeated by several others (bassman69504, mattsmark). The only datapoint I have to add to this is that my lamp is an OEM but has been working for almost 2 years now without incident.

Maybe the only other piece of information I can add is that I neglected to clean the air filter as rigorously as I ought, but frankly I've had the same pattern throughout the life of my TV (since 2002) and never had *this* issue before.

Anyone have an update on what to look for? I don't want to buy a new lamp if it's not the problem.
One more interesting note:

* When the screen shuts off on its own, the fan runs and the lamp light flashes four times indefinitely.

* When I turn OFF the TV before the TV auto-shuts off, the power goes out, and the fan turns off as would be normal.

On my TV I have checked fuse F1701 and checks OK, but the green light remains blinking and no image. Should I go ahead and install "Panasonic Ballast Repair Kit", #LSUC0022 to address the issue?

what filter did you change? there on the lcd unit.
Cheers

Does anyone know what filter is this and where? Is this somewhere inside the light engine?

I'm reviving this old thread because I think it has lots of useful info.

My PT-45LC12 is on 3rd lamp, second thermal fuse and original ballast. Recently, the TV starts only for 30 secs or so and then lamp shuts down with the red light blinking 4 times (but see update below). According to troubleshooting, the lamp overheats and one is supposed to clean air filter. Well, the filter is clean.

It took the filter and lamp out and started the TV to check the fans. I could see both the rear duct fan spinning as well as the fan behind the front filter. This means the fans are good, right?

I also checked the thermistor next to the filter and it reads OK at 57 kohm, but the one next to the lamp (R2901) is only 240 ohms. Should be 290 kohm according to an online tip I found by googling (cant post the link according to the site rules). But, maybe that an error and it should be 280 ohms?

Update:
I misread the blinking light. It was lamp light 4 blinks and not temp light 4 blinks. I put my old reserve lamp in and it works like a charm (except for dark output due to its 4600+ hr life). So, it looks like I got almost 3500 hrs from cheaper Osram bulb (#69374 RPP022). Will order a similar soon. What I like about Osram they are sealed and not vented like the OEM bulbs. This is important as the original OEM bulb exploded (at only 2500 hrs) venting mercury into the house.

I have a PT-45LC12. I recently moved and when I plugged it in and pressed the power button, it comes on and starts the automatic scan for channels; however, after about 15 seconds it shuts off on its own and the power button begins to flash amber one time every 5 seconds. I read that the code for this is fans 1, 2, or 3 may be bad but I have checked the fans and they are all working. I also made certain the filter was clean. If I unplug it and plug it in again this cycle repeats its self... any ideas from anyone out there???

the filter is made of thin foam within a removable holder located under the right speaker cover which pulls right out just like the one covering the access to the light bulb.