How to fix my Samsung tv ..picture goes in and out intermittently

I'd look at a bad panel, the defective panel damaged your main, replacing that got it working somewhat but if it's on very long I'm guessing you will damage the main board you replaced. Try unhooking the ribbon connectors one at a time and see if half the picture works ok, if so you definately have a bad panel

It could be a defective main board, or intermittent LED diode on the back lights strips.

I will try a new main board first.

Ask them to replace the t-con board. It could be a defect one.Good Luck.

Serge.

Check the power supply circuit for bad capacitors, you can tell which are bad by their bulging tops.

Could be an issue with the lamp ballast causing intermittent operation.

If this tv is a Samsung HCM4215W with the symptom you described you are likely to have fluid leak on the board. Sounds like a classic fluid leak problem since the audio does come on and then going intermittent. If you find fluid from the tube(s) on the board then the set could not be worth fixing unless you can break up the fluid with degreaser spray. The fluid is conductive and will cause intermittent or shut down altogether the set. Look for the fluid as a clear substance. Also you may have a bad proscan board (module) Comes on with audio and no picture then on/off REPLACE PRO SCAN MODULE BP95-00077A. Do a search online for part for availability. But look first for the fluid leak.

0ne of 3 has failed:
(in order of probability):

1. Backlight inverter
2. Power Supply
3. Backlight

Please seek the expertise of an experienced TV repair technician - as they contain potentially lethal voltages that must be properly discharged before work can begin.

Thanks!(*&^%

you blew a circuit board

You need to check the back light is still on when the screen is blank (check through the back).

If the back light is on, need to change the Powwer Board.
but,
no back light, need to change the inverter.

I would take it to a repair shop, they charge around $50 to look it over, and then tell you want is wrong with it and they will give you the cost to fix it. This is what I do when TV's go out. It will save you time and money in the long run.