Brightness/Contrast Prob - Tosh 32wd98B

[Steve.norbury]

Can anyone help me solve my problem?

I have a 16 month old Toshiba 32WD98B TV which has recently developed a brightness and or contrast flickering problem. Sometimes its really noticeable, sometimes you can only just see it and sometimes it ain't there at all. I have managed through various experiments to establish that it is the set that is flickering and not due to any attached device. In other words with nothing plugged in except, ofcourse, the mains and selecting either direct TV or any of the then empty AV sockets (to get a steady blue screen) the flickering still occurs.

Picture quality in terms of clarity is not affected but it is really annoying. I have taken the back off and gave it a damn good hoovering inside thinking an accumulation of dust may be the fault however this has not rectified the problem.

It's almost as if there is voltage fluctuation with some component inside or EMC interference. Does any one have any ideas?

Another question, when I took the back off I had to disconnect a black and white wire attached to a black cylindrical case attached to the roof of the rear caseing. Whats in the caseing and what does it do?

I have no other probs with this TV and up until now would have recommended it to anyone. The picture quality has been fantastic with no geomatry probs and the like since day one. Have not once needed to access the system menu.

Hope someone can shed some light.

Steve N

 

[Olorin]

I am also experiencing the same problem where the brightness flickers randomly (32W8DB). My TV is about the same age as yours and I have found no solution I chatted to a service engineer today and he was at a loss too and said "It sounds like a nasty fault!" Bah! If u find a solution please let me know, and if any1 out there has any ideas please help us out as it is very frustrating.

Thx.

 

[Steve.norbury]

Thanks for your reply. I was beginning to feel rather lonely with the problem. It's driving me nuts. Everytime I see the flickering I try something new. I've resorted to switching of the Central Heating, the iron, the dish washer and other things in an attempt to find the cause. I firmly believe its either interference of some sort, dirty mains earth maybe or just some component with fluctuating voltage output. Whatever it is I wish it would just go away.

I have tried many fixes mentioned in this forum like changing the 2bs2 settings, to mention just 1, to 09H etc. I've tried moving the telly to another room all to no avail. Engineers have come and gone without any ideas.

What a real real shame because when it dosn't flicker the picture clarity and vibrant colours are fantastic.

I promise if a fix comes my way or I'm inspired into a fix I'll let you know. In the meantime any ideas welcome from any direction.

Steve N

 

[Philip Newton]

My JVC television did the same but it also showed up flyback lines. There was a part which was replaced by an engineer Transformer? not sure if this is right, but it was the part that sets the factory brightness, he fiddled with a switch and when he turned it the lines came up as white lines across the set and brightness went up. In conclusion he replaced the part that controlled this and it has stopped flaring and the lines are no longer around. It went wrong again and started flaring so they took it away and the report I got back said that someting to do with CRT had been changed and the greyscale was altered. Do you see faint white lines when the screen is black? Look to see if you can find a switch to tweak the brightness levels (this does not affect the same thing as brightness control) and see if that is working, if the lines show up regardless of whic way it is adjusted the chances are this is your problem sorry if this is a bit muddled maybe someone who knows more could set me straight

 

[Philip Newton]

Found This

25.30) Occasional brightness flashes

These may last only a fraction of a scan line or much much longer.

This could mean an intermittent fault in a variety of places including
the video circuitry and SCREEN power supply:

* Brightness circuitry - SCREEN, master background or its power supply.
Could be in or around flyback or focus/screen divider. Could perhaps
be in the CRT, but probably less likely.


if this is the case it seems that what my tech report says would indicate CRT problems. As the flyback transformer was replaced seems fine now the CRT has been tweaked