Samsung un58tu7000f cycles on and off

[ronl]

Hi Members.I was given this Un58tu7000f Samsung that cycles on and off.you can hear the sound,see a raster on the screen(no information) for a sec or 2 ,two flashes of the power led,then it shutsoff.turns back on in a few seconds and repeats. There is only a signal board and a power board.I unplug the power going to the signal board and backlights stay on.no cycling. Then I reconnect the signal board and unplug the output to the panel,it stays on with sound and raster.then I tried disconnecting one side of the panel and it stays on with sound and raster.it looks like its the signal board but I don't want to order one without being sure. Power board is bn44-01054c.signal board is bn- 9415565k. The tv was made aug 2020.Just curious what does the forum think? Thanks RonL