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Thank you very much again! Battery powering it was the most important thing for me. When I have free time I have to fix the other iMac, the one I started experimenting with and shorted out. As you suggested I'll go through the resistors on that data line to find out what is causing the "AC/DC T2...

@2informaticos YOU ARE A GENIUS!!! The NPN transistor is giving the logic board the temp readings so it is not missing the 7-pin data cable, which means I can replace the original ACDC power supply with a DCDC supply so it can be battery powered!! :)

Thank you. I will test this on Friday and I hope everything will go well.

@2informaticos can I just double check if I understood you correctly that I should solder the NPN transistor onto J6901 in a way that B+C are on PIN-5 and E is on PIN-4?

If I understand you correctly I solder B+C to PIN-5 and E to PIN-4 of J6901 and that should make the logic board think that the PSU temp sensors are connected as they should be even if the 7-pin data cable is disconnected? If I don't have access to any donor MacBook or iMac boards can I buy an...

Thank you very much for your detailed reply @2informaticos I really appreciate it. Out of curiosity I've checked the "iStats menu" sensors readings after disconnecting the 7-pin PSU "data" cable and I got the same readings as in my previous comment (comment #29) when the 7-pin cable was...

@2informaticos as you suggested I have replaced that chip with a new TMP423B from DigiKey. Problem still exists, CPU fan is spinning up to maximum speed, like when pins 4 & 5 were missing, even though the 7pin ACDC data cable is connected. This is what has changed now that I have replaced the...

OK, thank you, I'll buy one and let you know when I've changed it.

Both lines to ground are 0.696V, then reversing the multimeter leads produces open line.

What should I test next?

Yes

Strange but everything seems to roughly in the right place but there are some interesting differences. I have probed through and I've create a large photo that I have colour coded to show what is connected to what, you can download it here (the forum didn't let me upload it here because it was...

So it is somewhere else then, right? I will have to probe through and find where the J6901pin 4 & 5 lead me... hopefully I'll find it quickly. Do you have any advice how to trace them quicker?

Yes, it is DAFi

I've measured L5610/11 they are both 0.9 ohm. That means they are OK? The actual logic board is a bit different than the boardview. The main difference is the IC that is where U5600 should be only has 8 pins instead of 10 as on the boardview. I have attached a photo of it. Am I looking at the...

Thank you so much 2informaticos, that is brilliant!! I'll measure those as soon as I get home from work today. If one of those have burnt, where can I buy a L5610/11 or U5600?

Exactly. I haven't tried battery powering the machine yet, I always used the original power supply, this is what I've done: - Because I knew when I will use big batteries I won't have the 7pin data cable my first test was to just unplug the 7-pin data cable and start the machine (with the...

Thank you for the schematic 2informaticos. When I was testing connecting those 7 pins one-by-one, I've found that only pins 4 and 5 (SNS_ACDC_N and SNS_ACDC_P) are needed for the machine to work perfectly, which makes me assume that one or both of these two might be missing now after I...

Thank you both, I've found it it was just hard to see as it's black on black: 820-00609-A

Thank you for your prompt reply 2informaticos. Please help me find the 820 code of my board. Printed on the logic board I see two QR codes and some numbers below and another couple of numbers but unfortunately neither of those start with 820.