iMac - 27" - Mid 2010

[vaswaniraj]

Hi Team,
I have a 27" iMac - Mid 2010. I ran the EFI Test on it and I get the following error.
Voltage (VG0R) -- MXM (test 1) - Error - Sensor is reading below the low limit
Test Failed.

As I don't have the schematics for the iMac logic boards, can anyone point out for me as to where to look for that sensor so that I can fix this logic board.

Thanks

Raj.

 

[dukefawks]

Board is called "white angle" Google for diagram.
This voltage sensor is a simple resistor divider from the main 12V bus R5360/62. What is the sensor actually reading?
Is this the only failing sensor? Continue ASD on error.

 

[vaswaniraj]

Thanks Duke, I am out of town will post response tomorrow.

 

[vaswaniraj]

Hi Duke, I am not able to find any diagram on google. Is it possible to help me find out where can I find the R5360/62 so that I can get this iMac fixed.
Also regarding your question, if that is the only sensor failing - The answer is yes.
Regarding the sensor actual reading, I am not aware of that.

 

[dukefawks]

Ridiculous

820-2901 is available everywhere.

 

[vaswaniraj]

Thanks Duke

 

[vaswaniraj]

Hi Duke,
Thanks for all your help. I found out that one of the resistors R7116 was shorted to ground. After removing that resistor the short is gone. I had one more question. The resistor R7116 has a value of 20K with 1%, 1/16W, MF-LF , 402.... This is too technical for me to understand. But my question here is that I cannot find the exact resistor as per the specifications of R7116 but instead I have some donor boards which says the following value... 20K, 5%, 1/16W, MF-LF, 402.. Is it OK to use a 5% instead of a 1% resistor. If not, then what is the next alternative to replace this resistor. Your help shall be highly appreciated. Thanks Raj.

 

[dukefawks]

Hopeless, what does R7116 have to do with voltage sensing?!

Also it says 20 on the diagram as in 20 FUCKING OHM Raj! Yeah that will beep on diode mode DUH!

 

[vaswaniraj]

Duke, i have never done this in my life. I never studied what is Ohms law. Yes I understand that my answers are weird, but then how do i learn. Whenever i ask questions, I am kicked away and treated like, don't ever ask your questions again, on this forum.

 

[dukefawks]

I'm sorry. I did my masters on Ohm's law so I studied it for 7 years. I can understand that after only a year doing repairs you don't fully understand how to measure a 20 Ohm resistor.

 

[vaswaniraj]

Duke, i can say one thing. If I am explained once how it works, I don't forget, but my basics need to be cleared. Before going for Jessa or Louis class last year I never did this. I only used to change screens and parts replacement, which I had made it clear on Rossmann's website where in they ask the background before coming for the course.

 

[vaswaniraj]

I apologize if I have been rude in any way. My emotions sometimes run high due to lack of success and ending up to a failure.

 

[larossmann]

Pages 9-21 in the sheet I gave you go over ohm's law, resistors, how resistors are measured and how they usually fail with graphics. Read it!