SOURCE: Hitachi 55" Plasma HDTV, 1 yr old, suddenly lost picture and sound, but power light still on.
It sounds like a shutdown circuit is being activated. This is normal in cases where the power supply id drawing excessive current. I would suggest that you get this looked at by a qualified professional. This is because this problem may be in the power supply and the voltages can get dangerous in this section of the TV set.
In any event if this is a power supply problem chances are the technician will just have to replace the power supply. Which should cost from 150-250 dollars.
I hope this helps
Shuttle83
SOURCE: Hitachi Plasma TV model P50H401
I think you have problems with the digital main PWB.
If the power PWB failed, turn off and change the pilot ligth to red.
SOURCE: Problem with Hitachi P50H401 Plasma TV - Will not
I have the same model, P50H401 and it developed the same problem two days ago. This set is 2 1/2 years old in service, being purchased in December 2007. The original manufacture date was October 2007.
The set was turned on and operating at the time and then promptly shut down by itself. The front blue LED power indicator began flashing four times in a loop or cycle.
The flashing LED sequence in this instance points to a problem with one of the following boards: PSU, X-Sus, Y-Sus or SDRs (there are two SDR boards, SDR-U and SDR-D, both are connected off of the Y-Sus board on the left hand side of the frame when rear facing). The set shuts down to prevent further damage to other boards or components.
I could power cycle the set but it would shut down after after a few seconds. Power LED would stay solid, I could hear the PS relays switching, and audio would output through the speakers. Then as the screen was just about to illuminate, the entire set would just shutdown. The blue LED would again go into the 4X flashing sequence.
I could not visually detect any signs of severe component damage on the main PS board. The two large electrolytic capacitors which have been mentioned as problematic in other threads seems fine. The where slightly raised on the top surface, but not blistered or completely blown open.
The only indication of component damage that I could detect visually was on one of the small surface mounted ICs on the SDR-U board.
Through reading other posts on this site, I learned that I was able to remove the suspect SDR-U board and then re-power the set. Doing this proved that the PS, X and Y Sus, and the SDR-D boards where o.k. The PS held, and the lower half of the screen illuminated. (I would only do this for as brief a period as required to determine if the the other boards would function and the screen would illuminate. Do not pro-long operation in this state so as to not cause further damage.)
It was somewhat difficult to locate the correct SDR-U board. My local service rep did not have one in stock, and the Canadian parts distributor was also out of stock. They estimated 10 - 14 business days to order one up from the U.S.A. (Hitachi closed their consumer electronics division in Canada back in 2009.)
By chance, I checked with another service rep in an adjacent town. He had a board for the P55. We did a visual comparison on the two boards and determined that it would be compatable.
The easy part was removing the defective SDR-U board and installing the replacement. The hard part was re-alinging the three ribbon tabs into the respective connectors on the SDR board. Be careful with these ribbons. The other end of each is fused to the plasma panel screen, so if you damage them, your screen is rendered useless.
I initially had the same problems as others have posted with having black or gray lines on the screen when the SDR-U was replaced. After gently adjusting the position of the ribbons as they are seated in the connectors, the lines disappeared. This was a slow and frustrating procedure, but it worked, Be patient.
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