Toshiba Regza 37" LCD TV Repair - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 19 Old 07-18-2014, 01:48 AM - Thread Starter
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Toshiba Regza 37" LCD TV Repair

Hi I got this faulty Toshiba Regza 37" LCD TV, model is 37AV550E, manual can be found here.

It's able to power up and works fine but after running for ~45mins, the picture will goes blank and the audio is still playing, I can also feel the back of the TV is kinda hot.

This happens to all input sources, hdmi, tv, ...

Feel wasted if throwing it away, I took a picture when it's running fine.


Any advise on how to fix this?

Last edited by ABuNeNe; 07-18-2014 at 08:48 AM.
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post #2 of 19 Old 07-18-2014, 02:27 AM
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Quote:
Originally Posted by ABuNeNe View Post
Hi I got this faulty Toshiba Regza 37" LCD TV, model is 37AV550E, manual can be found here.

It's able to power up and works fine but after running for ~45mins, the picture will goes blank and the audio is still playing, I can also feel the back of the TV is kinda hot.

This happens to all input sources, hdmi, tv, ...

Feel wasted if throwing it away, I took a picture when it's running fine.


Any advise on how to fix this?
Something in the CCFL power supply, probably.
I have a friend with a Regza and the fluorescent tubes are getting dim with age.
When the set first powers on, the picture is very weak, but it gets back to full brightness gradually.
Yours sounds like something in the high voltage transformer circuit overheating and shutting down.
How long before it will come back on? The older Regza pictures are very nice -- better than newer
LCD backlighting for color spectrum. You should get it fixed!
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post #3 of 19 Old 07-18-2014, 08:25 AM
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Quote:
Originally Posted by ABuNeNe View Post
Hi I got this faulty Toshiba Regza 37" LCD TV, model is 37AV550E, manual can be found here.

It's able to power up and works fine but after running for ~45mins, the picture will goes blank and the audio is still playing, I can also feel the back of the TV is kinda hot. Any advise on how to fix this?
Do you have DIY electronics experience like using a meter and soldering?
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post #4 of 19 Old 07-18-2014, 08:32 AM
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Not so much -- I can check to see if there is an open circuit, but you already know that's happening.
I wonder if you could operate the TV with the back removed and possibly not overheat?
The manual link doesn't open for me. Maybe someone will pick this up that is more helpful. Sorry!
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post #5 of 19 Old 07-18-2014, 08:51 AM - Thread Starter
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Originally Posted by hammerdwn View Post
Do you have DIY electronics experience like using a meter and soldering?
Yes, I've used multimeter and done soldering before.

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Originally Posted by johnfull View Post
Not so much -- I can check to see if there is an open circuit, but you already know that's happening.
I wonder if you could operate the TV with the back removed and possibly not overheat?
The manual link doesn't open for me. Maybe someone will pick this up that is more helpful. Sorry!
Sorry, have fixed the link.

I'll try to open up the back and take some pictures, especially on the inverter board.
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post #6 of 19 Old 07-18-2014, 09:09 AM
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Quote:
Originally Posted by ABuNeNe View Post
Yes, I've used multimeter and done soldering before.


Sorry, have fixed the link.

I'll try to open up the back and take some pictures, especially on the inverter board.
You need a service manual or the ability to read the schematic printed inside the rear cover.
The owner's manual isn't going to be much help with parts replacement, is it?
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post #7 of 19 Old 07-18-2014, 02:30 PM
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Quote:
Originally Posted by ABuNeNe View Post
Yes, I've used multimeter and done soldering before....
Take off the back and carefully inspect the Power Supply board and Inverter board(s) for bulging capacitors. If you see any, replace them (requires exact value capacitor and soldering).

See example pictures of bulging capacitors

If you don't see any, then you need to check the DC voltage (usually 24v or 12v) being supplied by the Power Supply to the Inverter(s) when the back lights are dropping out. If the voltage is ok, then you can try replacing the Inverter board(s). If that doesn't help then the back lights inside the panel are bad and you can't really do anything about that except buy a new Tv.
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post #8 of 19 Old 07-18-2014, 08:38 PM - Thread Starter
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Quote:
Originally Posted by hammerdwn View Post
Take off the back and carefully inspect the Power Supply board and Inverter board(s) for bulging capacitors. If you see any, replace them (requires exact value capacitor and soldering).

See example pictures of bulging capacitors

If you don't see any, then you need to check the DC voltage (usually 24v or 12v) being supplied by the Power Supply to the Inverter(s) when the back lights are dropping out. If the voltage is ok, then you can try replacing the Inverter board(s). If that doesn't help then the back lights inside the panel are bad and you can't really do anything about that except buy a new Tv.
Hi thanks for your reply. I did not find any bulging capacitors on the power supply and also the inverter board. I've took some pictures too.

Spoiler!


I might be able to find a replacement board for the inverter for a cheap price.

I'll try to measure the voltage later.
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post #9 of 19 Old 07-19-2014, 11:22 PM - Thread Starter
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Originally Posted by ABuNeNe View Post
Hi thanks for your reply. I did not find any bulging capacitors on the power supply and also the inverter board. I've took some pictures too.

Spoiler!


I might be able to find a replacement board for the inverter for a cheap price.

I'll try to measure the voltage later.
To addon, when it goes blank, I can see the picture when I shine a torch on it.
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post #10 of 19 Old 07-20-2014, 04:36 AM
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To addon, when it goes blank, I can see the picture when I shine a torch on it.
Backlight failure.
Could be the power supply or could be the fluorescent tubes themselves...
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post #11 of 19 Old 07-30-2014, 01:44 AM - Thread Starter
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Hi guys, I managed t find some time and do some testing and I noticed that if the tv is powered on without the back cover, it's running fine but with the back cover on, the backlight will goes off less then 30mins.

I also measured the input voltage to the inverter board and it's 23.8v before and after the backlight goes off.

Does this mean the power supply board is working fine and the problem is caused by the inverter board? Could it be cause by the t-con board or other components?

Please advise.
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post #12 of 19 Old 07-30-2014, 06:36 AM
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Quote:
Originally Posted by ABuNeNe View Post
...the input voltage to the inverter board and it's 23.8v before and after the backlight goes off.

Does this mean the power supply board is working fine and the problem is caused by the inverter board? .
Inverter board(s) or backlights inside the panel. Only chance to fix the Tv is replace the inverter board(s). If that doesn't fix then you are done because panel costs almost as much as a new Tv (if you can even find it).
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post #13 of 19 Old 07-30-2014, 08:59 AM - Thread Starter
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Hi I managed to find a hair dryer and blew it on the inverter board, focusing particularly on the transistors (with regard to this post) and after 30 secs, the backlight went off.

There are 4 transistors, wordings on them are DJ36AH FDD 8447L, in this inverter board, am I correct to say one, particularly the one on the most right, or maybe more of these transistors are faulty?

Spoiler!


Please advise what is my best option, add heatsink, change transistor or change inverter board?
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post #14 of 19 Old 07-30-2014, 09:07 AM
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If it were me, I would change the board.
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post #15 of 19 Old 07-30-2014, 10:41 AM - Thread Starter
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If it were me, I would change the board.
Hi hammerdwn, thank you for all of your replies.

I can get this replacement inverter board for a cheap price. But it's look kinda different (yellow instead of purple capacitors, all transistors are placed straight whereas mine, the transistor second from the left is slated. Do you think it's ok to get it?

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post #16 of 19 Old 07-30-2014, 11:45 AM
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pictures of both boards?
part numbers of both boards?
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post #17 of 19 Old 08-11-2014, 03:08 AM - Thread Starter
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Update. I got a replacement board, 6632L-0522A, and replaced the inverter board. After using for about an hour the same problem come back.

Anymore idea before I give up and throw the tv away?
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post #18 of 19 Old 08-11-2014, 06:38 AM
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Originally Posted by hammerdwn View Post
Inverter board(s) or backlights inside the panel. Only chance to fix the Tv is replace the inverter board(s). If that doesn't fix then you are done because panel costs almost as much as a new Tv (if you can even find it).
sorry, nope
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post #19 of 19 Old 08-11-2014, 08:50 AM - Thread Starter
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sorry, nope
alright, thank you and others for all of the replies!
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