Problem Atari power supply help

[Body pop]

I checked at the power supply (big connector plug unplugged )
I never actually checked with that plugged In as couldn’t get multimeter in there
So I would need to follow those points you showed me to somewhere I can get the multimeter on it then

 

[Ace`]

You can check at the power supply with the plug plugged in and power off to see if the resistance is very low, you will then know you have a short or not. You just don't know what's causing it this way but it's a start.

 

[Body pop]

So checking at the power supply it’s showing 0 .
At the power supply with big plug plugged in
That’s in dc mode
On smart it shows this

 

[Ace`]

With the machine OFF and the meter set to this setting (ohms) what reading do you get?

 

[Body pop]

Thanks 🙏
Below I took readings
First is with all connectors off pcbs
Machine turned off and big plug attached

next reading pic -with one (bottom)power connector removed from pcb

Last pic is reading with all connectors off pcbs

Is there any clues there ?