What board would be needed to repair hitachi 55hdt79 lost picture sound ok?

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

Can't post a solution to this problem post. Need more details.

SOUNDS LIKE YOUR UPPER AND LOWER BUFFER LOGIC BOARDS TOOK A DUMP.

It might be the power supply, check the main power supply. Audio power supply is seperate to main power supply, thats why you have a sound.

I can't help you because after 26 months of ownership mine is doing the same thing (started on 7-12-09). Judging by the number of people with the same complaint I believe Hitachi knows that they have bad boards but refuses to replace them for customers unless they are within warranty. It also explains why the merchant that sold it to me in 2007 stopped offering Hitachi in 2008.

I'm disgusted because I'm anticipating a $300-$500 repair bill simply because Hitachi's design did not provide an external way of resetting it. Impossible to get to the menu to do a reset within 12 seconds before it starts the powering on booting cycle again.

Adding salt to the injury, mine is wall mounted and repair people will only work on it if it is readily accessilble when they walk in the door or if it is brought to the shop. Know what a 55" plasma TV weighs? Too much.

that power supply is a switch mode power supply,which means it looks for an input signal to turn on.
that signal comes from the main pc board.
if there is excessive current draw,it will shut down.
check the input,and the screen circuit it is driving

Almost for certain your power supply board is bad, Can be repaired at the component level only if you have some electronics savy! Good Luck!

Dude, you dont have the same problem thanks for junking up my post.

Ok, so I have replaced the SUB power assembly and the SUB Defconvergence board, picture looks decent however magic focus just blanks the screen out and cannot adjust manually does the same thing.

Is there a way to enter the service menu and initialize the magic focus functions after servicing.

It must be using the saved ROM settings, but it wont let me adjust anything convergence wise.

Thanks,

Joe

There is a repair kit, for the PIP module, as thats where your problem lies. if you know how to solder on and off surface mounted capacitors, its a breeze to do, but if you dont, you will most likly put to much heat on the board and the landings and printed circuit traces will come up, so if you decide to do this yourselfs, please be carefull. The kit is available at this link.http://www.mcminone.com/search.asp?keyword=Hitachi+PIP&btnSubmit.x=10&btnSubmit.y=8 If you do not feel comfortable do this, maybe you know someone whos an electronic hobbiest and can replace these for you .. Good Luck PS please do not forget to rate this thread.

When you say you have tried all the inputs you are not clear if you mean tuner, vcr, dvd, aux, etc. If you are talking about only the cable input it sounds like you have a bad tuner. To obtain picture in picture there are 2 tuners in your set. This would explain why the small picture is ok while the main picture is bad. You should be able to swap the signals (see your ops manual). Try this. If the snow moves the one tuner is bad. If you have put other signals in (besides cable)such as dvd then the problem is in the matrix circuitry where the two signals merge. Either problem should be easy for a good tech to solve and not cost a whole lot.