Riddled TV Repair Forum

phreakboy · Joined: 27 May 2008 Posts: 1 Location: coatesville, pa

I have an older 720HD tv set that I picked up from a friend of my its a 62" projection tv. Now there is a problem with the set that I am looking for some help with. When you try to turn the tv on it will not come on, what will happen is you will hear a high pitch sound and an LED on the main power board will be lit now occasionally if you press the standby button on the front, the tv will come on and work fine sometimes for a day, sometimes for a month, and sometimes for and hour and then all of the sudden there is a loud high pitched sound and the tv will go off and the led on the main power board will be lit again. Now the only thing that you can do to get it back on is to unplug any of the connectors at the top of the board for the other components. while it is powered up. If you unplug one the high pitch sound will change and then when you plug it back in you can press the standby button again and it will work again for the time being. Nothing else will make it come back including unplugging the tv for quite awhile, that is the only way. However you can do it right away, as soon as you loose the picture if you unplug one of the connectors and put it right back it will work again, sometimes for an hour, day, month or more.

I would really like to fix this tv, as I do like it, I have also pulled out the boards and taken a look at them and do not see any burnt connectors, or swollen capacitors or anything out of place so I am hoping someone on here can give me some good advice to solve this dilemma

Google

Jesse Mack · Joined: 22 May 2008 Posts: 600 Location: The Last Frontier

I do not have tech lit on this model. however, if you can identify the power supply section, look for domed or expanded capacitors (electrolytic type). If you do have the lit, check the feedback and coupling capacitors in the SMPS as they can cause intermittent on-off and squeeling problems.

Hope this helps

Jesse