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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Toshiba 36" cinema series

 

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jfleming01
Novice

Jul 3, 2008, 8:31 AM

Post #1 of 28 (359 views)
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Toshiba 36" cinema series Can't Post

Hello
I have a 36" toshiba that recently started showing a horizonal white line in the middle of the screen. The past few weeks I have been able to hit the side of the unit and the picture would come back. Now I can not pull the old fonsarelly move (spelling)
From the readings that I have read on the forum this past week it appears that there is an issue in the vertical deflection circuit. I am pretty hand with a sodering gun and have been working for an electrical company for the past 12 years, but not in circuit boards. I have experience in low voltage and high voltage controls so I think I may have a shoot at fixing the unit with some assitance.
What kind of feed back can people offer to getting me going in the correct direction and locating the correct components? Also is this just a replacement component that I can purchase and replace?
Model: CN36G97 Chassis: TAC9731 Serial: 95576990
thanks in advance


(This post was edited by jfleming01 on Jul 22, 2008, 3:48 PM)



Repair man
User


Jul 4, 2008, 10:18 AM

Post #2 of 28 (346 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

Hello, this is probably just cold solder on the vertical IC. In most Toshiba sets the number on the board is IC301 (that's the most common # but not always the #). It will be a smaller IC mounted to a heat sink. Generally the constant heating & cooling of this IC while the set is on and off will eventually cause cold solder issues and often they just require re-soldering. Be careful not to create solder bridges (by this I mean do not accidentally solder two legs together) -- Dan


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jfleming01
Novice

Jul 15, 2008, 7:44 AM

Post #3 of 28 (313 views)
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Re: [Repair man] Toshiba 36" cinema series [In reply to] Can't Post

So I finally got into the set last night and started poking around. The bad part is that the TV set has been repaired in the past and I found some pretty shady repairs.
On to the initial problem.... I could not locate the IC based on the part number so I began the tap test to the major heat sinks and I quickly located the one that was creating the problem. I powered the set down and closely examined the solder joints and components and I did not see any thing that jumped out at me. Next I proped up the board and powered the set back up. From the under side of the board I was touching the solder points with a little wooden dowel trying to wiggle or find any loose connections. So I found the one creating the problem and as I checked it one last time to verify that I was on the right one the TV then powered off on its own. I was a little confused so I unpluged the set, pluged it back in and hit the power button. Now....the TV powes on as you can hear/feel that the high volatge has powered up , however the power light on the front of the set is just blinking now and the picture never comes on anymore.....
Any Idea??
thanks


techchris
Veteran

Jul 15, 2008, 4:39 PM

Post #4 of 28 (302 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

you didnt say if you had resoldered the ic as advised.


jfleming01
Novice

Jul 16, 2008, 3:11 PM

Post #5 of 28 (296 views)
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Re: [techchris] Toshiba 36" cinema series [In reply to] Can't Post

I have not as of yet, the TV shut off so I was going to chase that issue....


techchris
Veteran

Jul 17, 2008, 4:54 AM

Post #6 of 28 (287 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

you may have dry jointed other connexions on the ic and the microprocessor has shut the tv down.do the easy things first dont give yourself extra work for nothing


jfleming01
Novice

Jul 21, 2008, 9:40 PM

Post #7 of 28 (268 views)
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Re: [techchris] Toshiba 36" cinema series [In reply to] Can't Post

I fixed all the cold solder joints that I could find..... Plug the TV in, the high voltage works as I get static on the front of the screen, however the power light is still flashing.....What is the next step or direction I need to go to....

thanks



In Reply To
you may have dry jointed other connexions on the ic and the microprocessor has shut the tv down.do the easy things first dont give yourself extra work for nothing



techchris
Veteran

Jul 22, 2008, 8:49 AM

Post #8 of 28 (260 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

try turning the lower screen voltage adjustment on the flyback transformer clockwise to see if a raster appears .if you only have a horizontal line then the scan ic is probably faulty


jfleming01
Novice

Jul 22, 2008, 10:41 AM

Post #9 of 28 (258 views)
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Re: [techchris] Toshiba 36" cinema series [In reply to] Can't Post

why would I have to make adjustments when the set worked fine prior to me poking around on solder joints..... if you read the above post you will see where I was talking about poking around on the solder joints finding the loose one than one time a little spark happened on the loose joint and shut the tv picture off. ever sense that I turn on the set and the power light just flashes....


In Reply To
try turning the lower screen voltage adjustment on the flyback transformer clockwise to see if a raster appears .if you only have a horizontal line then the scan ic is probably faulty



onetech
User

Jul 22, 2008, 11:28 AM

Post #10 of 28 (255 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

That little spark probably blew the vertical output I.C. and the microprocessor is shutting the set down to prevent any further damage. Replace the I.C.


jfleming01
Novice

Jul 22, 2008, 12:05 PM

Post #11 of 28 (253 views)
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Re: [onetech] Toshiba 36" cinema series [In reply to] Can't Post

Where do I purchase a IC how do I know the part number etc.

thanks

In Reply To
That little spark probably blew the vertical output I.C. and the microprocessor is shutting the set down to prevent any further damage. Replace the I.C.



Repair man
User


Jul 22, 2008, 7:56 PM

Post #12 of 28 (240 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

 There are many electronics suppliers on the net I use several. Here is one of them Click Here But first you have to look at the front of the IC and read the part number on it. Vertial IC often start with LA (for example LA7838) They don't always start with this, this is an example only. The IC will probably only cost a couple of dollars, it will cost you more for shipping than the part is worth. You can check it out at the site I mentioned above. If it is going to be too much, let me know the part number, I may have a used one on an old chassis you can have.
When removing the IC it is sometimes easier to remove the heat sink it's fastened to by de-soldering it as well and remove them together -- Dan


________________________
Learn LCD / Plasma TV Repair

(This post was edited by Repair man on Jul 23, 2008, 1:06 PM)


jfleming01
Novice

Jul 23, 2008, 10:49 AM

Post #13 of 28 (231 views)
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Re: [Repair man] Toshiba 36" cinema series [In reply to] Can't Post

It looks like mine is labeled TA8427K. Does this sound correct?



In Reply To
There are many electronics suppliers on the net I use several. Here is one of them www.electronix.com But first you have to look at the front of the IC and read the part number on it. Vertial IC often start with LA (for example LA7838) They don't always start with this, this is an example only. The IC will probably only cost a couple of dollars, it will cost you more for shipping than the part is worth. You can check it out at the site I mentioned above. If it is going to be too much, let me know the part number, I may have a used one on an old chassis you can have.
When removing the IC it is sometimes easier to remove the heat sink it's fastened to by de-soldering it as well and remove them together -- Dan



ernie
User

Jul 23, 2008, 11:22 AM

Post #14 of 28 (227 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

that will be the right ic la8427k just a couple of £s in the uk


jfleming01
Novice

Jul 23, 2008, 1:04 PM

Post #15 of 28 (217 views)
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Re: [ernie] Toshiba 36" cinema series [In reply to] Can't Post

Mine was a "T" Not an "L"



In Reply To
that will be the right ic la8427k just a couple of £s in the uk



ernie
User

Jul 23, 2008, 1:06 PM

Post #16 of 28 (215 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

sorry my mistake put l instead of t so still the right one


jfleming01
Novice

Jul 23, 2008, 1:13 PM

Post #17 of 28 (213 views)
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Re: [ernie] Toshiba 36" cinema series [In reply to] Can't Post

Thanks

In Reply To
sorry my mistake put l instead of t so still the right one



Repair man
User


Jul 23, 2008, 1:33 PM

Post #18 of 28 (211 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

TA8427k is also a vertical IC -- Dan


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Learn LCD / Plasma TV Repair


jfleming01
Novice

Jul 25, 2008, 2:55 PM

Post #19 of 28 (194 views)
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Re: [Repair man] Toshiba 36" cinema series [In reply to] Can't Post

Parts should be in today when I get home, so hopefully I can get all this stuff off my floor and back on the stand tonight....

In Reply To
TA8427k is also a vertical IC -- Dan



jfleming01
Novice

Jul 25, 2008, 6:34 PM

Post #20 of 28 (187 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

Well I have installed the IC. I am having trouble with one of the joints taken a solder. any how now I have a horizonal white line and about 2" of black and white pixels below the line

when I plug in the cable input the 2" actually show a picture. The 2" section is also not square as the sides kind of slant inward.





In Reply To
Parts should be in today when I get home, so hopefully I can get all this stuff off my floor and back on the stand tonight....

In Reply To
TA8427k is also a vertical IC -- Dan




(This post was edited by jfleming01 on Jul 25, 2008, 7:07 PM)


Repair man
User


Jul 26, 2008, 8:59 AM

Post #21 of 28 (176 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

OK you're almost there. Don't run the set with this small picture or you will burn out the vert IC again. The problem you have now is probably a capacitor right near the Vertical IC. It will be one of the electrolytic capacitors (they're the tubular looking caps standing up). they will have a black stripe down one side. Pay attention to the direction they are in; the black stripe is the negative side of the capacitor. Change all caps in the area of the vert IC. It is a good chance that it will be the cap connected to pin 5 of the IC (this is the output pin) Follow the trace lines from the IC and see if it leads to a cap. I'm guessing at the value being 1000uf at 50volts. This is a guess only of the value. there may be 2 or 3 caps near the IC you should change and they will all be different values. Change them with exact values. Caps are cheap approx. 50cents each.
I hope this helps, I will be away until Tues, I'll check in then -- Dan


________________________
Learn LCD / Plasma TV Repair


jfleming01
Novice

Jul 26, 2008, 9:05 AM

Post #22 of 28 (171 views)
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Re: [Repair man] Toshiba 36" cinema series [In reply to] Can't Post

Is three any where local that I can buy these or am I ordering them all again. The last 1.47 part cost me 20 dollars buy time I met there minimum and shipping...


In Reply To
OK you're almost there. Don't run the set with this small picture or you will burn out the vert IC again. The problem you have now is probably a capacitor right near the Vertical IC. It will be one of the electrolytic capacitors (they're the tubular looking caps standing up). they will have a black stripe down one side. Pay attention to the direction they are in; the black stripe is the negative side of the capacitor. Change all caps in the area of the vert IC. It is a good chance that it will be the cap connected to pin 5 of the IC (this is the output pin) Follow the trace lines from the IC and see if it leads to a cap. I'm guessing at the value being 1000uf at 50volts. This is a guess only of the value. there may be 2 or 3 caps near the IC you should change and they will all be different values. Change them with exact values. Caps are cheap approx. 50cents each.
I hope this helps, I will be away until Tues, I'll check in then -- Dan



jfleming01
Novice

Jul 26, 2008, 2:27 PM

Post #23 of 28 (163 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

which cap are we discussing that need replaced?





Front and back view photos


(This post was edited by jfleming01 on Jul 26, 2008, 2:28 PM)


Repair man
User


Jul 29, 2008, 4:55 PM

Post #24 of 28 (146 views)
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Re: [jfleming01] Toshiba 36" cinema series [In reply to] Can't Post

Hello, I'm back, when I last wrote I mentioned the caps would have a black stripe, well your's have gray stripes, this is normal (it all depends on the manufacturer) When replacing then make sure the negative gray stripe goes in the same direction.
My first guess of which cap to change would be the small one closest to the IC. In the image all I can see of it is that it is a 35volt cap and what looks to be 100uf (because all I can see in the image is 100), but check it close in case it's 1000uf. If it is 1000uf and you put 100uf in you'll damage the IC again.
If that cap doesn't fix it try any others in that general area and again see if they are soldered to a trace line that leads to the IC.

If you don't have a local store to buy these caps from you can just take them out of any old TV or electronic device that has the same value. The physical size is not important because different manufacturers will make caps different sizes (height / diameter etc.) but it is important that the value of the cap correct. It has to be the correct 'uf' value and the voltage has to be the same or higher. For example the cap I'm suggesting to change first is a 35volt cap, do not use less than 35 volt cap but you can use a 50 volt or 100 volt etc. what ever is available to you.

This line you are having could also be a result of the one leg you had trouble with (the one you said you couldn't get solder to stick to it) If this is the case, you could solder a small jumper wire from that leg to the next spot down the trace line that it is supposed to be soldered to. In other words, if you can follow the copper trace line that this leg is supposed to be soldered to, it will come to another point at which another component will be soldered (such as a cap or resistor etc) you can solder a thin gauge wire from the leg of the IC to the next point of that trace line. -- Dan


________________________
Learn LCD / Plasma TV Repair

(This post was edited by Repair man on Jul 29, 2008, 5:06 PM)


jfleming01
Novice

Aug 7, 2008, 9:22 AM

Post #25 of 28 (109 views)
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Re: [Repair man] Toshiba 36" cinema series [In reply to] Can't Post

Dan
Thanks for the reply, I am just getting back from being in cali so hopefully I can get back after this set this weekend.

I will keep you posted



In Reply To
Hello, I'm back, when I last wrote I mentioned the caps would have a black stripe, well your's have gray stripes, this is normal (it all depends on the manufacturer) When replacing then make sure the negative gray stripe goes in the same direction.
My first guess of which cap to change would be the small one closest to the IC. In the image all I can see of it is that it is a 35volt cap and what looks to be 100uf (because all I can see in the image is 100), but check it close in case it's 1000uf. If it is 1000uf and you put 100uf in you'll damage the IC again.
If that cap doesn't fix it try any others in that general area and again see if they are soldered to a trace line that leads to the IC.

If you don't have a local store to buy these caps from you can just take them out of any old TV or electronic device that has the same value. The physical size is not important because different manufacturers will make caps different sizes (height / diameter etc.) but it is important that the value of the cap correct. It has to be the correct 'uf' value and the voltage has to be the same or higher. For example the cap I'm suggesting to change first is a 35volt cap, do not use less than 35 volt cap but you can use a 50 volt or 100 volt etc. what ever is available to you.

This line you are having could also be a result of the one leg you had trouble with (the one you said you couldn't get solder to stick to it) If this is the case, you could solder a small jumper wire from that leg to the next spot down the trace line that it is supposed to be soldered to. In other words, if you can follow the copper trace line that this leg is supposed to be soldered to, it will come to another point at which another component will be soldered (such as a cap or resistor etc) you can solder a thin gauge wire from the leg of the IC to the next point of that trace line. -- Dan


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