The red “on/off” indicator blinks but TV wont turn on.

Hello, So I haven’t been able to get my Tv to turn on, I took it for repairs and the gentleman said he replaced the power supply board, I think it was, and when I showed up to pick it up, the TV was on and working. I brought it home and installed it but again, it wouldn’t turn on. I returned it to the shop and told him the issue so he took it apart again and double checked everything and once again when I show up, it’s working, this time he said he used a brand new board instead of recycling a used one in good condition from an old TV (so I wouldn’t have to pay the cost of the new board). So, I double check the TV before loading it in my car and taking it home.

Once again…I install the TV and the thing won’t turn on! I decided to just leave it be for a while until I could research more or take it to another shop; until recently, when I randomly decided to plug it in and it worked! Until I turned it off cause it’s not like I’m going to leave the TV on for the rest of its life?

So that’s the backstory.

The issue: The TV wont turn on.

What happens: The screen stays black. The red indicator turns off as if trying to turn on the TV, then it turns back on to say the TV is off.

What I’ve Tried as a fix:

Ive tried to use different outlets to plug in the TV.

Ive tried holding the power button on for 10 secs.

Ive removed the power cord and tried holding the power button like that.

Ive removed all hdmi cables and other “foreign” or “external” devices.

Ive air-cleaned the circuits.

Ive begged it and I’ve cried.