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Hitachi 50UX26B no picture no sound

My Hitachi 50UX26B has no picture and no sound. When the power is turned on, the red protection led (D975) comes on along with the 5 green power leds (D950, D951, D952, D953 and D954). Almost immediately (1 sec or less) leds D953 and D954 go out. Then leds D950, D951, D952 dim and go out and the red led (D975) flickers a few times and then reamains steady. Fuses F902 (5A) and F906 (1.6A) are both good and have never been replaced. I have closely inspected component and trace sides of the power circuit board and haven't found any obvious problems (burnt components or traces).

I guess I'm ready for the next step!!!

Thanks.

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  • 7 more comments 
  • jekitt Dec 05, 2007

    Is this the only option I have, or are there any other diagnostics I can perform. Or possible "common" problems/failures cures to try first?

  • jekitt Dec 05, 2007

    I'm sorry, I should have mentioned that I've replaced IK04, IK05, IK06 and I601 (the only replacements so far). Didn't make any difference.

    Terryfic: What is E944? I don't have it listed in the parts list and don't see it on the board. Likewise with the pico fuse. Where might these be located on the board.

  • jekitt Dec 08, 2007

    OK...Latest update:
    I checked resistance of pin 8 on I601 and pins 7&9 on IK05, 05, 06, C708, C709, R706, R711, R712. Didn't find any shorts. I reinstalled the board to check voltages on IK06 (easiest to reach) pins 7&9. When I powered up, D975 flickered 4 or 5 times and then came on and D953 & D954 went off almost immediately (as before). I shut the tv of and for about 10 secs and powered up again. Same thing. Powered down and connected my voltmeter to IK06 pin 9 and powered up. This time D975 come on steady but all green leds including D953 & D954 stayed on. (Found out later that having the DVM connected was a coincidence!) IK06 pin 9 measured +27.0v and pin 7 measured -25.78v.
    When I tried the menu button on the front panel, all I got was a few colored stripes horizontal across the center of the screen.
    I also noticed an intermitent "chirping" sound coming from the board in the area of the power supply. Asneer as I can located the chirp is coming from inside the shield surrounding the power supply area. After a short period of time, D953 & D954 would go out. May be coincidence but as neer as I remember, this cycle of 3 powerups would repeat. I think I have a bad electolytic cap that heats up and shorts.
    Any thoughts??

    Thanks!!

  • jekitt Dec 09, 2007

    OK..I followed the troubleshooting flow chart to "A" and checked pin 5 of I901 and the voltage was well below 10v-16v. I am going to check the recommended components today along with the components you suggested.
    PS: in this context, does LOL mean "laugh out loud" or "lots of luck"?!!!!

  • jekitt Dec 09, 2007

    Oh yeah, I forgot to mention in my last post, the heatsink for I901 and D901 gets moderately hot fairly quick and seems to hottest near I901.

  • jekitt Jan 29, 2008

    arwilson,
    Since the holidays are over, and I have nothing better to do, I thought I'd get back to this monster!!
    I replaced I901 (twice! the first was also bad). Now the power stays on, all green led's stay lit but the red protection led still stays on.(Sometimes I have to cycle the tv on 3 times to get the green leds to stay on). I don't have that electronic component "chirp" I used to have and the heatsink for I901 stays considerable cooler.
    I followed your last advice but didn't find anything. I took some voltage readings as follows:
    Q609: Base 26.6V, Collector .06V Emitter 26.6V; Q601, 604, 605, 606, 607, 608, 610, 612, 613 all check ok to voltage chart on schematic. I601 (which I replaced earlier):
    Pin 1@11.1V, 2@4.4V, 3@5.5V, 4@5.6V, 5@.06V, 6@5.1V, 7@.04V, 8@26.6V, 9@.06V, 10@.06V, 11@.06V, 12@25.4V, 13@26.6V. It seems I have a problem at Q609/I601. Should I replace I601 again? Any suggestions??
    Thanks.

  • jekitt Jan 29, 2008

    The symptoms are same as before. The led's usually won't stay on when powered up. If I cycle the power off/on 2 or 3 times, they'll stay on (the red led is not as bright as the green). When I hit the menu button I get horizontal "swoosh" lines across the center of the screen. The volume looks the same way and the input is not legible. Have included pictures.











    Thanks.

  • jekitt Jan 29, 2008

    maklean,
    Try these links:
    http://www.eserviceinfo.com/downloadsm/1...

    This is the service manual. Must download all 13 parts and then use the following link to assemble them into the manual:
    http://www.rarlab.com/

    This software has a 30 day free trial.

  • jekitt Feb 02, 2008

    arwilson,

    I cleaned the board with acetone and looked it over with a magnifing visor. The next to the last place I looked, I found a broken trace. When I inserted the replacement I601 earlier, which I didn't need to, (following the Hitachi troubleshooting chart) the solder pad on pin 12 lifted slightly. Couldn't see it with the naked eye! One of the two traces broke disconnecting L601. I repaired the trace and finished inspecting the rest of the board. When I reinstalled the board this is what I got:






    I believe the orignal problem was solved when I replaced I901. This is the only replacement component that made any difference. The TV has been running for about 15 hrs and turns off and on with no problem. Looks like we got It!!!

    Thanks so much for your help.

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I see that you have high voltage but you do not have any vertical deflection.
I would suggest to replace IC601 (vertical driver/amplifier). The part number is LA7838 or a replacement NTE7039. It looks like you may have some additional problems with this set because the horizontal line is not straight, so maybe the convergency ICs may be also defective.
Good Luck.

Posted on Jan 30, 2008

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Mine is sony tv,i have the same problem i have solved it by the following method.
Does the light blink or flash? If so, tell me how many flashes or blinks before it starts over again. That is a Sony diagnostic code. (See www.fixyourowntv.com)

The indication is the set has gone into protection overload.

First thing to do is a hard reset: Just unplug the power cord for about 1 hour, then power it up again.

If the reset does not clear the problem you will need a servic tech to look in and do some testing to see what section has the problem. The protection mode is caused by one of the 8 sections/circuits from drawing too much current. It is most often the main power supply but can be any where within the system. And, it always takes some testing and diagnosis to locate the problem.
 

Make sure a authorized service expert looks at it because they would have the necessary technical information on your set. You might call two or three repair places and get their idea; you will need the model number and they would be able to tell you if that set has a service bulletin or other outstanding information available.

here is asite from where you can solve all your problem:- 

http://en.allexperts.com/q/TV-VCR-Stereo-1749/indexExp_71672.htm

Good Luck
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Hope this helps.

Posted on Jan 30, 2008

  • 2 more comments 
  • PRIYABRAT  PATTANAIK
    PRIYABRAT PATTANAIK Jan 30, 2008

    1) R706,R711,R712 check resistance (ohms).
    2) The power supply components would be C921, C930, Q915, D     914, 920, 921 and R920. Check Q 609 in the vertical circuit and   related components D605, 606, 607, 608, 609.
    Try this site for your manual:-
    www.HitachiService.com

    Just do what i say,you will be benifitted.

  • PRIYABRAT  PATTANAIK
    PRIYABRAT PATTANAIK Jan 30, 2008

    1) R706,R711,R712 check resistance (ohms).
    2) The power supply components would be C921, C930, Q915, D     914, 920, 921 and R920. Check Q 609 in the vertical circuit and   related components D605, 606, 607, 608, 609.
    Try this site for your manual:-
    www.HitachiService.com

    Just do what i say,you will be benifitted.

  • PRIYABRAT  PATTANAIK
    PRIYABRAT PATTANAIK Jan 30, 2008

    Try the link for electrical repair shop. :-
    http://en.wikipedia.org/wiki/Hitachi,_Lt...

    Good Luck
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  • PRIYABRAT  PATTANAIK
    PRIYABRAT PATTANAIK Jan 30, 2008

    Official Hitachi products information, software, brochures, specifications, reviews and technology guide link:-

    www.hitachidigitalmedia.com/

    Goodluck,
    Dont forget to rate me as fixya..

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Hi,

If your TV has an on screen menu function, can you see the menu when your press the menu button. It's hard to say what the problem may be without actually seeing the TV, however the problem with no sound or picture could be due to a tuner or a tuner control fault.

The problem with your set could be a bad vertical deflection system. The repair is not cheap.

My recommendation is this: Before doing anything, just bang on the set a few times with your hand to see if there is something loose inside that will, with some agitation, bring back the picture. YOu never know, it may come back to life. If nothing simple seems to improve it, then it should be disposed of.

Goodluck,
Dont forget to rate me as fixya..

Posted on Jan 29, 2008

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Dude, your'e in the right track BUT you'll be also in danger.. DON"T YOU EVER TRY mess up those wire connections or your'e gonna FRY the motherboard that EASY. You don't want to put yourself in misery, do you? THE BEST SOLUTION to your problem is that you should have it checked to a liscensed technician to solve your problem AT ITS BEST LEVEL.ok?

Posted on Jan 29, 2008

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Because D953 and D954 go dim right away indicates a short in th +27v and -27v line. The most likely suspects are IK04, IK05 (convergence output IC1s). The other suspect is I601(vertical output chip)

Posted on Dec 05, 2007

  • 4 more comments 
  • Anthony Wilson Dec 07, 2007

    Check the resistance of pin 8 on I 601 and pins 7 & 9 on any of the convergence IC`s( IK04,05,06) to ground. If any pin measures low ( less than 1000 ohms) Check the neighboring components for shorts. If you find a low, you can also follow the copper trace and lift one leg of the suspected component from the trace untill the resistance checks high. The voltage at pin 8 & 9 is +26v pin 7 -26v under normal operation. If you have a meter that measures Min/Max you can see if your voltage ever gets to 27 on startup. I am still asuming that your initial obsrevation of D953 & D954 are correct. Hope this helps.

  • Anthony Wilson Dec 08, 2007

    Hmmmm. The horizontal lines across the center suggests that we have a vertical problem. The power supply components would be C921, C930, Q915, D 914, 920, 921 and R920. Check Q 609 in the vertical circuit and related components D605, 606, 607, 608, 609. It would be helpful if you have an ESR cap checker. Sometimes you can put your finger on the top of the cap and feel if it gets toasty hot. (not normal) Leaky caps can also give off a nasty odor. Keep at it, persistance always triumphs in the end. LOL

  • Anthony Wilson Dec 10, 2007

    LOL Laughing out loud. I Like your version better, lots of luck. The point is you need to keep your sense of humor while encountering a stressful situation. If you change I 901 be sure to discharge C907 and C900 first.

  • Anthony Wilson Jan 29, 2008

    What is your current symptom now that the led`s stay on? By the way, the red led being on is normal unless it it very bright compared to the others.

  • Anthony Wilson Jan 30, 2008

    Wow! That is a good problem. Thanks for the picture. I don`t think changing the vertical output IC again will fix you nor the convergence IC `s. I would get some acetone and wash the board clean where you have been working so you can inspect the traces for any bridges or cracks. You might benefit by using an opti visor ( magnifier ) to get a close up view. If all is well, check the signal board near I-501(video jungle) see if there is any corrosion on the board from CRT leakage. If you have a schematic check for proper supply voltages around Ic-501.It wouldnt hurt to check the power supply again at the led`s for proper voltage. Have to go now, will check back later when I have time to study the schematic Good luck

  • Anthony Wilson Feb 04, 2008

    Good job! Sometimes when we work too hard tyring to fix things we need to clean up our tracks. Acetone in my opinion works best. When I solder I always clean the traces to double check for breaks or bridges. Make a habit of this practice and you won`t spin your wheels as much. PS nice picture.

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C702 shorted E994 open is the most common problem.....
Use Sony cap # 1-161-754-00 .....102K / 3KV
Check pico fuse value = 4 amp ??.........................T.

Posted on Dec 05, 2007

  • 1 more comment 
  • Vista Electronics Dec 06, 2007

    Pico and micro are small fast-acting fuses soldered in to

    protect each B+ source......there are certainly more than

    the two glass fuses in your set....either there is an open fuse

    or an open resistor or still something shorted...............

    E994 is a pico fuse in a newer chassis......................

    Have you researched your model at www.HitachiServiceUSA.com..........?................T.

  • Vista Electronics Dec 06, 2007

    jekitt,

    Sorry. I gave you info for wrong chassis.....Let's try again...

    1) Check C708 , C709

    2) Check R706 and R711, R712

    3)After No Raster flow chart, drop down to B ..........Did you check F903 ?.....Follow the flow chart..............



    Comment ?....................................T.

  • Vista Electronics Dec 08, 2007

    See Dec 6 comment .........................................................

    2) R706,R711,R712 check resistance (ohms)

    3)Did you check F903.....follow Flow leg B ??



    What I am suggesting comes from the manual........T.

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  • 306 Answers

The deflection board needs replaced.

Posted on Dec 05, 2007

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