820-00291 iMac 27" 5k 2015 no power

[lincev]

Would a thermal camera be convenient to see which component is heating up?

 

[2informaticos]

OOOPS!!!
Checking ohm scale with power connected???

 

[lincev]

Yes, I have checked the power pin and I have 3V but in the points that I tell you in the resistance scale 20k 200k etc. .. always value 0.000

They have lent me a mobile thermal camera (it does not have much quality) but I am not able to appreciate heat in Q3771 U3781.

 

[2informaticos]

You can NOT measure ohm scale, or diode mode on a powered board; is a big NONSENSE!!!

 

[lincev]

You have not understood me well, excuse me. I know I can make a short film this way.

I only commented on having a voltage of 3v in the power connector so that I knew that the source was connected and that everything was correct. I didn't want you to think it had a value of 0 ohms because of a bad power supply connection or a problem with this part. Sorry.

 

[lincev]

hi again I have connected the board so that I can measure on the other side and on pin 2 of L7610 on the 200k scale I have a value of 21.8

I have connected the board so that I can measure on the other side and on pin 2 of L7610 on the 200k scale I have a value of 21.8

But continuity only gives me on pin 1 so I don't know if this helps ... because the short seems to be at the other end of the track

 

[2informaticos]

"You can use voltage injection method."

Start with 1V and go up if needed, no more than 4V.
Set first the amp limit of lab PSU at max.