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Hitachi Projection TV issue, suspected fly back transformer

I have a Hitachi CT4532 45" projection TV, and getting the following behavior. When the TV is turned on from cold it usually starts squeezing the picture in from the top and bottom within a few minutes. It will then shrink a little more then the picture will disappear then it has to be turned off for 15 mins or so (it varies) before you can try again. BUT sometimes it will work without trouble and will work

100% until it is turned off again. And it worked for more then a week without trouble until it was turned off. AND if the picture is squeezing in a little bit (1-2" from the top and bottom) I can usually change channels until the squeezing stops and then it will work fine until turned off again. When changing the channels it does not slowly disappear it will all of a sudden be working. A note that may help, the horizontal output transistor has been replaced twice in the past but this problem did not exist at those times. It came around about 2 months after it was replaced the second time. I don't have the equipment to test the fly back .... Could it be anything else? Its way to big to take somewhere and I cannot afford a tech right now as I'm going to be going back to school for a MSc. Please help .. - Eric
Reply to
Charon
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Sounds like dry solder joints in the Vertical Deflection section.Remove the chassis and inspect the area around the Vertical Out IC. Resolder all in that area ,whilst in there ESR the filter caps in the Vert Section.

Reply to
kip

Agreed. If the top and bottom are closing in you have a vertical deflection problem.

Check this tip:

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HITACHI CT4532

Vertical Def Shrunk

A1 Tv John

Resolder Stand Up Brd On Power/Def Board. .Board Is Located Almost In Center. There are Three Little Transisters On The Board , They break Loose.

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-- ========================== Jeff Stielau Shoreline Electronics Repair

344 East Main Street Clinton,CT 06413 860-399-1861 860-664-3535 (fax) snipped-for-privacy@snet.net ========================
Reply to
Shoreline Electronics

I tried resoldering the transistors on that board. The three transistors only have two of the pins soldered. And the middle pin is snipped off on all three. I think the one that is cut is the collector. I really hope that did the trick otherwise im not too sure where to go next. I will know soon. How do I find the vertical out IC ?

The main board in the tv will be a pain to get out. Many wires soldered onto it.

- Eric

Reply to
Charon

Reply to
kip

Well, the original soldering of the transistors, I did a poor job. And I did not manage to fix it. So I went back in and did a much better job of it and since then I have not seen the problem of the top and bottom squeezing in. Looks like the problem is fixed. If not Ill just move on and resolder other items linked to the vertial output. Thanks a bunch guys. As I think the cost to fix the TV would have been more then its worth.

Reply to
Charon

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