Hitachi 55HDS52

[thekiltman85]

Good afternoon,

I have a Hitachi 55HDS52 plasma TV. I got this from someone who claimed it had sound and no picture. In fear of damaging more components I did not plug the TV in to confirm. I removed the back panel and noticed that an IC on the lower buffer board was fried. I replaced the lower Y buffer board and the Y sustain board. Once the new boards arrived I plugged them in but to my dismay the TV would not turn on. No power to the set and no LED indicator lights. I unplugged the ysus from the power board and still no changes. I attempted individually and then all together removing boards that were connected the PSU but nothing changed. I also changed the fuse in the PSU filter (not sure that's the technical name) but nothing happened. Does this sound like a bad PSU or should I try something else first. Visual inspection of the CAPS on the board appear to be fine. Any advice would be greatly appreciated.

Best Regards,
Aaron

[sordids999]

Re: Hitachi 55HDS52

pictures of your boards may help more with fixing your problem

[thekiltman85]

Re: Hitachi 55HDS52

Alright thank you. I will take pictures of the boards and post them here.

[thekiltman85]

Re: Hitachi 55HDS52

Attached please find photos of the boards from the TV. If you need anything closer let me know. Or photos of the other boards. I took photos of the Y sustain board, the Y buffers, the power supply board, and the power filter board.

[R_J]

Re: Hitachi 55HDS52

You did turn the MAIN power switch on I hope?

[thekiltman85]

Re: Hitachi 55HDS52

Well you win this round. Thank you for the advice. I totally forgot this TV had a separate power button. You've brought life back into my project, however the TV still has sound and no picture. I had ordered both a replacement lower y buffer, and a replacement y sustain board. When I replaced them both the same symptoms arise. I unplugged the upper buffer and did not get a half picture. I then unplugged the lower buaffer to same result. Could it be possible that one of the boards was DOA? Thanks again,

Best Regards,
Aaron

[thekiltman85]

Re: Hitachi 55HDS52

What's the best way to determine which of the boards is bad? The new y buffer board I received is really bunged up. I sent it away to a repair service on ebay and it came back looking pretty shoddy. That being said the seller/repair person had very positive reviews and does many transactions each month. How can I isolate which board is the problem? I'm pretty amateur at this. Just started repairing TV's as a hobby. As you can see by my replacing the boards, and not repairing the IC I'm still very new at this.

Cheers,
Aaron

[MagicSmoke]

Re: Hitachi 55HDS52

If it has sound then PSU is making some of the voltages the tv needs to operate. Some TV's only need 2 or 3 voltages to operate, Plasma's can have 5 or more to function properly.


First check all Stby voltages on PSU when tv is off. There may be more than one voltage present in Stby. my vizio has 4, 3.3v 5v 9v and 24v when tv is off.


Then check VA & VS on PSU with tv powered on, VE volts on X board and Vscan on Y board.


Edit... Any leds flashing on Logic/Control board when on?

[thekiltman85]

Re: Hitachi 55HDS52

Alright I'll try and pull out the multimeter and get a read on the voltages. Usually there should be a print somewhere on the tv or the board itself right telling you what the proper voltages are?

[MagicSmoke]

Re: Hitachi 55HDS52

Yes volts should be printed on board, may or may not be next to the connector. Some are on the back side of board.

VS, VA, VE and Vscn are HIGH VOLTAGE!!!! There should be test points for each. If not back probe the connector.

VS & VA are on the PSU, VE is on X board, Vscn is on Y board. These will only show when set is powered on.

If Vs comes up for just a second and quits then there is a problem somewhere.

Edit... there should be a panel sticker indicating what the voltages should be.

[thekiltman85]

Re: Hitachi 55HDS52

Good evening,

Sorry for the delay. I had to go buy a new multimeter. I did that tonight and should be able to take measurements shortly. In the process of checking boards however I managed to accidentally break off one of the black plastic clamps that holds the ribbon connector down on the y sustain board. Any advice for an alternative means to hold it in place? Thanks in advance,


Best Regards,
Aaron

[thekiltman85]

Re: Hitachi 55HDS52

Good evening,

Sorry for the extreme delay. I've been very busy with work and haven't had time to mess with the TV. I want to do things the safe way and not risk frying myself. The last thing I need is to end up in the news as the idiot who accidentally killed himself working on a TV. Can you point me in the direction of a guide (on this forum or otherwise) for how to test the voltages on these boards? Obviously the amount of electricity running through these boards is pretty high.

Also I connected the new Y sustain board (first one was dead) and Y buffers and the screen lights up now, but it's white with black horizontal lines. I removed each buffer independently to no change. The bottom buffer produces colored lines but no picture. Anything there is just multicolored lines but no discernible picture. There is still sound. Thanks again,

Best Regards,
Aaron

[thekiltman85]

Re: Hitachi 55HDS52

New Symptoms have arisen. This morning I plugged in the TV and hooked up my laptop through the HDMI. I was able to stream pandora with audio and a discernible picture. The picture however, had thin black horizontal lines running through it and the colors were distorted. As well there was a thicker black bar running along the bottom of the panel. Slightly adjusting the lower ribbon cable on the lower buffer board made slight changes to this line. I would have taken a picture but it didn't last long enough. The TV didn't like when the laptop went to sleep and went into standby mode. After that I lost all audio and picture. I attempted to restart the panel which showed a green indicator light but it was dark with no picture. Isolating the problems


1) Thin black lines and distorted colors
2) Intermittent picture.

Any advice would be greatly appreciated.

Thanks again,
Aaron

[MagicSmoke]

Re: Hitachi 55HDS52

Sounds like bad Y buffers. There is a video on how to test them on youtube.

[thekiltman85]

Re: Hitachi 55HDS52

Would bad Y buffers account for the lack of any picture at all, or just the distortion? I replaced the Y sustain board and the lower y buffer. With the new sustain I got the TV to light up intermittently but not with any consistency. The first Y sustain board I received was DOA. The new one appeared to work and as you suggested made me suspect that my new buffer and the old one as well were bad. I'll test them later and find out. If I run the test and it comes back negative then what?


Thanks again,

Aaron

[thekiltman85]

Re: Hitachi 55HDS52

Good morning,

I tested the Y buffer boards and neither one of them appears to have a short. I had tested other buffer boards I had from another TV that had audible shorts on them, but these are not shorted.

Best Regards,
Aaron

[MagicSmoke]

Re: Hitachi 55HDS52

Any leds flashing on/off on the Logic/Control board when powered on?