Toshiba 32HL67U LCD Vertical Stripes

[LDSisHere]

Hello,

I am hoping that someone can help me out with this TV. This is what it does:

After the power button is pushed, multicolored bars appear on the right side of the screen.

Then the screen goes dark for a split second, then the bars come back with the video image showing on the rest of the screen but kind of dim, the sound works correctly.

A split second after you can see the image the screen goes dark and you can no longer see any images, the sound continues to work.

I have attached an image of what the screen looks like when you can see the video image.


Every capacitor looks good visually and are good brands. It seems I may have two problems, one being the vertical stripes and the other 2 Seconds to black. Could one problem be causing the other? If the TCON board is bad could that cause both the lines and the back lights to turn off? Suggestions on which problem I should troubleshoot first and what part I should concentrate on would be much appreciated.


Thanks,
Lloyd

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

Everyone has different troubleshooting techniques and since budm and tom66 work on TVs a lot, they could probably tell with one look where to start.

It might be a bad panel, but I can't tell for sure.

1) Does the on screen menu show the same symptoms?

2) Have you tried cleaning and reseating every possible cable inside the T?

3) Can you take voltages readings to make sure they all are within specifications and steady?

4) Have you tried flexing the TV to see the problem goes away (tab bond)?

[tom66]

Re: Toshiba 32HL67U LCD Vertical Stripes

My guess is a failed driver or tab bond for that portion of the display.

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

Everyone has different troubleshooting techniques and since budm and tom66 work on TVs a lot, they could probably tell with one look where to start.

It might be a bad panel, but I can't tell for sure.

1) Does the on screen menu show the same symptoms?

Yes

2) Have you tried cleaning and reseating every possible cable inside the T?

I have reseated all of them that I thought could affect the screen in this way.

3) Can you take voltages readings to make sure they all are within specifications and steady?

I have take some from the TCON board. The test points marked with a voltage were good. There were some others I am not sure about because I have no idea what they were supposed to be in the first place. I will have to see what I did out of the manual but I am not sure the TCON board is in the manual.

The manual I found for this is an HTML one that requires the ZEUS engine and DWF viewer so it was a real pain to get working. I have to load an XP virtual machine just to view it.

4) Have you tried flexing the TV to see the problem goes away (tab bond)?

My guess is a failed driver or tab bond for that portion of the display.

I did a little bit but I did not get any change. I looked up similar issues on this site while I did my initial troubleshooting and got the idea that the vertical stripes were either a TCON or tab bonding issue but I wanted some feedback in case I was mistaken. I did not want to tear the screen apart unnecessarily but I now see I have no choice. I did see on here where someone was able to fix a failed tab bond with some tubing or foam to apply pressure so I will give that a try.

Thanks for taking the time to reply and I will let you know what I discover.

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

Vertical stripes / bad image:

I pulled the frame off of the screen and checked the tab bonding and the circuit board it is attached to for shorts and opens. I could not find any faults with the tab bonding. I had some foam that is used for DIP IC's so I put it about the two tabs that are in the area of the vertical stripes in case there was a problem I could not detect. I did not find anything with shorts or opens on the circuit board.

I reassembled the TV enough to test it but the results were the same, also pressing on the frame in the area of the foam made no difference even though I could fell the foam resisting my pressure.

After studying the image that would appear on the screen when it would flash on, I am now convinced the problem is in the TCON board. It has all the symptoms found in BudM's guide for the TCON and a few other threads I have looked through. Before I go spending money on a TCON board I need to get the 2 seconds to black problem solved.

Two Seconds to black:

This is what I have tested so far:

All the required voltages are there and steady. VBL, BL_ON and DIM

The capacitors are Rubycon ZLH and tested 0.02 - 0.03 on my Blue ESR tester so I do not think they are the problem.

I tested the SMD caps, resistors, and FETs for shorts/opens but found none.

All the secondary windings on the transformers have less than a 3% spread with a nominal value of 1200 ohms. I even re-soldered all of the transformer connections on the off chance one had a bad connection.

What I need to test:

I need to test the CCFL's now but this is where I am stuck. This board does not have the normal connectors for CCFL bulbs. You cannot connect/disconnect one at a time. The board slides into the sockets all at once. I did not get a picture of the CCFL side but you can see the small blade connectors on the edge of the inverter board in its' picture. What I need is a way to drive the CCFL's individually to see if one or more is bad if it is possible. Any suggestions on how I can verify the bulbs are good other than a visual inspection (opening the screen up) would be appreciated.



I am now convinced that I am a magnet for crazy problems and non-standard hardware.

Thanks,
Lloyd

[budm]

Re: Toshiba 32HL67U LCD Vertical Stripes

Did you do the transformer's resistance checking yet?
Can I see the label by the inverter connector?
What do you see at DIM pin? Read with DC meter and AC meter? It may be the same as this one: Just read it till the end of the thread.
https://www.badcaps.net/forum/showth...t=25892&page=7

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

I have been able to fix my 2 second to black problem. I have a handy CCFL bulb tester but it is only supposed to be good for bulbs less than 300mm so even if I could connect it I did not think it would work but I was mistaken. It took a little thought but I came up with a good improvisation to connect it since this screen does not use the standard connectors. The first two pictures show my solution. I was able to determine the seventh bulb down was not working prior to disassembling the screen. After dis-assembly I tested them again and took the pictures. The seventh bulb down had cracked on the left end.

I thought that I could get the replacement bulb I needed from another 32" screen that I had replaced for a co-worker due to impact damage. Of course it was too long to work. In the sixth picture you can see one of these bulbs and a shorter bulb I had ordered to repair a monitor but was too big for that job.

Since these two were my only options and there was no way to shorten the one that was too long I went with the shorter of the two bulbs. Some may be aghast at this repair but all I can say is that it works. The screen will now stay lit so I was able to get a better picture of the "real" problem.

I would like to think the problem is TCON board but I am not 100% sure that it is the problem. I do not think it is the tab bond(s) because of my prior testing. I am however concerned that it may be the main board. Is there any way I could easy verify which one is the problem or should I just order the TCON first to see if it solves the problem? Any suggestions as to my best course of action would be appreciated.



Thanks,
Lloyd

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

Let's see a picture of the t-con. I have only been able to recall 2 or 3 things that are user replaceable on the t-con. Namely, bad voltage regulator, shorted MLCC cap and a bad IC (I have to find the thread).

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

Well I was not smart enough to remove the thermal pads on the day I was able to take a picture of the TCON board in the sunlight so I have two picture versions. The one with the pads in good light for reference and the one without the pads with the best light I could do at the time. The third image is one that is edited to make locating the following points easier.

IN = ~5.1V
VIN = ~5.1V

VCC_1.8 = ~1.8V
VCC_2.5 = ~2.5V
VCC_3.3 = ~3.3V

VREFL_H = ~6.5V
VREFL_L = ~0.7V
VREFU_H = ~14.5V
VREFU_L = ~8.5V

BM1 = ~0 ohms
BM2 = ~0 ohms
BT5 = ~0 ohms

The voltage readings are within a few hundredths of a volt of what was displayed on the meter. I checked the capacitors for shorts and the resistors for shorts and opens but found none. The BM and BT items seemed to be shorts but I am not sure what kind of devices they actually are, they look like SMD capacitors but they seem to be more grey where the capacitors are more tan and marked with "c". I have no idea what the "VREF" readings should be but they did not "feel" right to me which is why I included them.

Any suggestions of what I should check or do from this point would be appreciated.

[tom66]

Re: Toshiba 32HL67U LCD Vertical Stripes

I would suspect the panel.
http://www.youtube.com/watch?v=98a8iMokMcY

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

The BM and BT items seemed to be shorts but I am not sure what kind of devices they actually are, they look like SMD capacitors but they seem to be more grey where the capacitors are more tan and marked with "c".

The "B" might be a ferrite bead. The "M" and "T" seems to indicate what subsection they are on the t-con board.

A ferrite bead should measure shorted.

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

I would suspect the panel.
http://www.youtube.com/watch?v=98a8iMokMcY

@LDSisHere. Seems easy enough to take apart and see if you have the same problem as the video above.

PS. Good ingenuity on the ccfl extender to fix the 2 seconds to black problem.

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

I would suspect the panel.
http://www.youtube.com/watch?v=98a8iMokMcY

@LDSisHere. Seems easy enough to take apart and see if you have the same problem as the video above.

I have to respectfully disagree that the problem is with the tab bonding for the following reasons.

1. Removing the frame and flexing the tabs by hand did not alter the picture in any way shape or form.

2. The screen has 6 tabs so logic would dictate that the problem would be in increments of 1/6th the screen width and that is not the case. The active horizontal screen length is 27 3/8". The striped area is 6 3/4" in horizontal length which is about one and a half tabs worth.

3. In all the other instances of the tab issue I have seen discussed, the rest of the picture was normal. The rest of the image in this TV is shadowed so bad that it is almost double images which I understand to be a sign of a bad TCON.


Could I be mistaken and the problem be the screen as suspected? Of course, but I got this TV to gain experience in troubleshooting and repairing them so I want to make sure I have explored all possible causes before throwing in the towel. My next step will be to put my money where my mouth is and order a replacement TCON to see if it will solve the problem or prove the screen is defective.

PS. Good ingenuity on the ccfl extender to fix the 2 seconds to black problem.

Thanks! I bought four of those bulbs for $20 and I did not think I would ever find a good use for even one of them when they would not work for their intended purpose. I sure did not want to spend the time or money to get a proper replacement either since this TV has more problems.

I want to thank everyone that has taken the time to look at my problem and I will report back when I get a board to try.

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

Could I be mistaken and the problem be the screen as suspected?

I'll be the first one to tell anyone that my analysis of any problem is not a 100% correct for two major reasons.

The first is that electronics is not my area of expertise. It is only a hobby for me.

The second is that remote troubleshooting is very difficult. If the device is in front of me, I might be able to use other senses (touch, smell, hear) that provides more clues.

Even in a "simple" case where someone posts pictures of obviously bloated caps on a power board, I'm never 100% sure if replacing them will fix the problem as there could be collateral damage.

The best I can do is eliminate the improbable and help find what is probable.

If you decide to get a t-con board, see which ebay sellers will allow returns. For example, this auction

http://www.ebay.com/itm/200879392052

states:

"You can return any item we sell within 14 days of arrival for a full refund. Buyer will be responsible for return shipping cost."

You may want to ask them if there are any conditions or exceptions to the above.

PS. Also keep in mind that 32 inch TVs have dropped significantly in price so sometimes repairing them may not be feasible depending on what you plan to do with this TV.

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

I forgot to mention that your new ghosting picture in post 13 looks like the problem (minus the obviously bad section) I have with a Toshiba. See

https://www.badcaps.net/forum/showthread.php?t=19939

While I have inserted vinyl bumpers and the TV appears to work, I have not tested it long term. It sits powered off in the corner for now.

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

If you decide to get a t-con board, see which ebay sellers will allow returns.

I already had a TCON on my watch list that was $29 including shipping which I ordered last night.

PS. Also keep in mind that 32 inch TVs have dropped significantly in price so sometimes repairing them may not be feasible depending on what you plan to do with this TV.

I do understand, that even working, this TV is not worth much if I wanted to sell it. The 32" size does make it much easier to work on verse a larger TV and its' value to me is in what I learn from the experience of trying to get it working. This kind of education is cheap if you compare it to the cost of a college course and a lot more fun IMO.

I forgot to mention that your new ghosting picture in post 13 looks like the problem (minus the obviously bad section) I have with a Toshiba. See

https://www.badcaps.net/forum/showthread.php?t=19939

While I have inserted vinyl bumpers and the TV appears to work, I have not tested it long term. It sits powered off in the corner for now.

I actually found and read through that thread yesterday. From what I have seen in my research, if the TAB Bond was the problem, flexing it would alter the picture in some manner.

I thought the resistor repair someone linked was very interesting. If the TCON board does not fix this TV then I may consider some radical experimentation myself. For now I will just play with some power supplies while I impatiently wait on my part to arrive.

Thanks again,
Lloyd

[LDSisHere]

Re: Toshiba 32HL67U LCD Vertical Stripes

I received my TCON today and installed it. The results were not what I was expecting that is for certain, I figured I was wasting my time and money on this board. The attached picture does not do justice to the actual picture, it looks better to the eye. My CCFL repair is slightly noticeable but not too bad. It will be livable until I decide what I want to do about it, if anything.

[tom66]

Re: Toshiba 32HL67U LCD Vertical Stripes

I am surprised it was the t-con. Thanks for posting the fix back!

[budm]

Re: Toshiba 32HL67U LCD Vertical Stripes

That is a surprised for me too, if you look at the other area of the screen, you can see double images also beside the vertical lines on the right.

[retiredcaps]

Re: Toshiba 32HL67U LCD Vertical Stripes

I received my TCON today and installed it.

Good job on the repair.

For your next repair, I'm covering all my bases.

Well it could be power supply or main board or inverter board or tcon!