Toshiba 37AV502R off/on

[foudl]

This tv shuts off by itself , i tested the caps on the psu and everything seems to be ok , i use the hair dryer to test one of them and it brings back the image and sound , so i changed the capacitor (c 207) it lasted one day then the trouble came back ,anyone else had this kind of prob ???

[selldoor]

Re: Toshiba 37AV502R off/on

Does it still come back on using the hairdrier? may be another cap in the vicinity
needs replacing - often suggest replacing all of same make/series.
Could also be a bad solder joint check with magnifier and resolder any that look bad.

[foudl]

Re: Toshiba 37AV502R off/on

Using hairdryer bring the tv back to life every time, if i look around the cap there is diode and transistor npn , i tested the voltages 24- 12 and 5 volts ,when the tv turn off , all the voltages are down 24 will go 11v, 12 will be down to 2 v and 5v is down to .5.

I wonder if the transistor can leak and do that kind of trouble?!?

[selldoor]

Re: Toshiba 37AV502R off/on

Not much I can suggest without pictures of your boards - see "sticky" for how to post
https://www.badcaps.net/forum/showthread.php?t=39740

[MagicSmoke]

Re: Toshiba 37AV502R off/on

If it has one bad cap then there are probably others. They don't have to look bad to be faulty.

I like to change all of the caps under 100v to try to prevent having to do it again in the near future.

Also don't use caps from Radio shack, they are general purpose and may work for a day or longer, but they will not last. Ebay is a bad idea too, many fakes.

You must use good quality low ESR caps in a PSU.

[nomoresonys]

Re: Toshiba 37AV502R off/on

could try digikey for capacitors, they're not outrageous on shipping like some others.

[Caleb]

Re: Toshiba 37AV502R off/on

not sure if it is applicable to the 37" but budm had a 32av502r with a leaky signal diode on the power supply causing an unstable 5v I believe it was d200 (smd 1n4148)

[budm]

Re: Toshiba 37AV502R off/on

In other thread for the same model I requested the OP to provide good clear pictures of the bottom side of the board to see if it uses the same circuits as the 32" but I never get the pictures I requested.
https://www.badcaps.net/forum/search...archid=4300100
This is the 32" version that I fixed:
http://s807.photobucket.com/user/bud...in=true&page=1

[foudl]

Re: Toshiba 37AV502R off/on

In other thread for the same model I requested the OP to provide good clear pictures of the bottom side of the board to see if it uses the same circuits as the 32" but I never get the pictures I requested.
https://www.badcaps.net/forum/search...archid=4300100
This is the 32" version that I fixed:
http://s807.photobucket.com/user/bud...in=true&page=1

Budm, the pics that you have show the very same kind of board, i'm trying to send pics of mine but it never upload , the diode d200 that you changed fixed your prob?,sorry again for the pictures ...

[selldoor]

Re: Toshiba 37AV502R off/on

Foudl -Your pictures are probably too big (reduce to less than 2mb) or if posting more than1, too big in total - try adding one at a time

[foudl]

Re: Toshiba 37AV502R off/on

https://onedrive.live.com/redir?resi...nt=photo%2cJPG

[selldoor]

Re: Toshiba 37AV502R off/on

Link doesnt work for me?

[foudl]

Re: Toshiba 37AV502R off/on

1

[foudl]

Re: Toshiba 37AV502R off/on

http://s1298.photobucket.com/user/ma...?sort=3&page=1

hope this is working.

[foudl]

Re: Toshiba 37AV502R off/on

As mention before to Budm the board is exactly the same for the 32 and 37 inches Tv

[budm]

Re: Toshiba 37AV502R off/on

Yes, it did fixed the problem, took me a while to find out until I got the IC SPEC. At first I thought it was the startup cap because when I heat up that are the 5VSTBY becomes steady, replaced the cap then it works for a couple days and then doing the same again, the 5V will be fluctuating, replace the diode with 1N4148 and the TV has been working ever since, I still have the TV at home.

[foudl]

Re: Toshiba 37AV502R off/on

Bud you make my day, the symptoms my tv is suffering is exactly the same, i'll go get this diode in the beginning of the week and i'll get back to you.

Happy new year to everyone by the way.

[selldoor]

Re: Toshiba 37AV502R off/on

Ok did it myself - dont know why anyone finds it difficult?

[KevinCro]

Re: Toshiba 37AV502R off/on

Hello guys. I know this thread is older but can someone link me to the right diode to purchase. I went to mouser and they had several different types. Thanks a lot.

[Caleb]

Re: Toshiba 37AV502R off/on

Smd 1n4148
Standard 1n4148
pick whichever you need