Hitachi 50ux26b No Picture

posted by scottvc on Oct 13, 2008

When pushing the power button, the red led comes on and stays solid, and we can hear a relay. Pushing the magic focus button we can briefly see some text, and it fades. Pushing the service button we get rows of vertical lines that are pretty sharp, and rows of really broad/messy horizontal lines. The TV was my wife's before we got married, so I have never messed with it to know what those two screens would/should look like anyway, and the manual is also long gone.

Opening the lower front and back, the red led D975 comes on, and stays solid. 5 other green leds also come on and stay solid.

Any help on where to start would be appreciated. Also, any input on where to find a service manual, schematics, or even a parts placement diagram. I do have previous electronics background as an avionics tech in the Navy for 13 years, but after 15 years of non-use and a lack of anything but a DVM for test equipment I'm hoping a not to expensive shotgun troubleshooting approach will do it. I think about the only thing I'm still confidant about is soldering, although looking in that TV getting the board out doesn't look too entertaining.

Any help, or more detailed questions I can check and get back to you with that could help, would be greatly appreciated!!!

Comment posted on Oct 13, 2008

Oh, a few things hit me on more detail or will likely be asked. We did try unplugging the set in an attempt to reset it multiple times. One attempt was actually for well over 24 hours even. Also, all inputs were unplugged by the time I got involved, but I am told the audio was working.

Comment posted on Oct 13, 2008

I wish there was an edit button so I could just change the original instead of adding to the list :)

The menu also does not display. Only thought it may be important since there is at least "something" being displayed when using magic focus or service mode. I guess my largest confusion is why all 5 green leds are lit and no clue where to start because of it.

Comment posted on Oct 15, 2008

Another update...

First, going into service mode the grid is now sharp, vut VERY dim. Can only just barely see it and nothing at all on about the top half.

Second, I did find a service manual. The Hitachi instructions say to turn the TV off, then back on and observer the led's to see which turns off first. I'm assuming they just wrote that backwards since unless an led is out completely, it is when the TV is turned off the leds also go off? In that case, when turning the TV off, D953 and D954 turn off significantly quicker than the remaining 3 led's.

If that is correct, I assume I need the 3 convergence IC's and 6 47k Ohm resistors.

My biggest, uneducated concern then is, with no picture, no menu/OSD, and if these parts are the cause, how does Magic Focus or service mode manage to display anything at all either, even if very dim or just part of the screen?

Comment posted on Oct 15, 2008

I removed the board this evening and checked all 4 fuses, and all are good as well :( Also checked solder joints on the bottom and didn't find anything. Also, before starting to remove the board I cycled power once more, and all led's appear to go out at the same time now when it is turned off, and all led's on when the set is on. No clue where to start. I do now have access to an O-scope if needed, but will have to wait for a weekend when it isn't needed.

I have the same problem