Psu DELTA ADP-200DFB / Logic Board voltages on iMac Intel A1311

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iMac Intel 21.5" EMC 2389

Model A1311 / Mid 2010 / 3.06 & 3.2 GHz Core i3 or 3.6 GHz Core i5 Processor

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POSEIDONE MERCEDES @poseidonem32310

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Опубликовано: 21 окт 2020 г.

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Psu DELTA ADP-200DFB / Logic Board voltages on iMac Intel A1311

Good morning

I’ve an iMac 21.5 mid 2010 A1311 EMC 2389

It boots only if I connect the cable while I keep pushed the power on button

Then it starts up with fans at max speed

Then I keep pushed the power button to turn off

Then I push power button and it starts up with fans at max speed

No chimes at all

That’s the only thing I can do

Also my Logic Board doesn’t have the SMC RESET button, is this “normal” ? On web I saw some logic boards with/without SMC RESET button.

Here voltages

Is there any other test to do ?

Psu broken ? Logic Board broken ?

Here diodes checked with multimeter on PSU, D3 should be blown, about D131 I really don’t know:

D1 = 480

D2 = 470

D3 = 0

D31 = 620

D32 = 634

ZD39 = 640

ZD36 = 655

D39 = 536

D33 = 538

D131 = 560 (-) / 1665

(By the way LCD is NOT plugged and just LED 1 is ON and I have already the ATG)

http://tim.id.au/laptops/apple/imac/imac...

Best Regards

My psu Delta ADP-200DFB

Good morning, I’m a new user, is site offline or there’s just a long queue to get an answer ?

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6 Комментариев:

How and why did you measure all the diodes? What values are those? Answers is not staffed by anyone. We are only volunteers on here trying to help each other out. Some questions get answers quicker because more volunteers have knowledge about it. Your question is very specific and may require lots of time to get answered.

24 окт 2020 г. из oldturkey03

@oldturkey03 Thanks for your message !After researches on web about my issue with iMac I did measure diodes with multimeter because they could be blown.

I could do more investigations about PSU if I would have the schematic diagram/datasheets.

At moment I wasn't lucky, I did contact also Delta at https://www.deltapsu.com/en/contact/supp...

And I did found also those sites for datasheets, maybe they can be useful for other users:

https://elektrotanya.com/showresult?what...

https://pdf.ic37.com/DELTA/brand.html

25 окт 2020 г. из POSEIDONE MERCEDES

POSEIDONE MERCEDES this does sound like a bad power supply. Have you checked the output voltages on it? Schematics are pretty much not available since none of these companies support the repair of their devices.

25 окт 2020 г. из oldturkey03

@oldturkey03 - Without this bit of info I would have agreed!

> Then it starts up with fans at max speed

> Then I keep pushed the power button to turn off

> Then I push power button and it starts up with fans at max speed

These tell me the power is getting to the logic board, so its something deeper within it. Measuring the logic board rails would be a good direction but without having schematics and board views it will be difficult.

25 окт 2020 г. из Dan

POSEIDONE MERCEDES your Logic Board should be a 820-2784-A Schematics and boardviews for that are readily available from the right places.

25 окт 2020 г. из oldturkey03

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How and why did you measure all the diodes? What values are those? Answers is not staffed by anyone. We are only volunteers on here trying to help each other out. Some questions get answers quicker because more volunteers have knowledge about it. Your question is very specific and may require lots of time to get answered. — oldturkey03
@oldturkey03 Thanks for your message !After researches on web about my issue with iMac I did measure diodes with multimeter because they could be blown.

I could do more investigations about PSU if I would have the schematic diagram/datasheets.

At moment I wasn't lucky, I did contact also Delta at https://www.deltapsu.com/en/contact/supp...

And I did found also those sites for datasheets, maybe they can be useful for other users:

https://elektrotanya.com/showresult?what...

https://pdf.ic37.com/DELTA/brand.html — POSEIDONE MERCEDES
POSEIDONE MERCEDES this does sound like a bad power supply. Have you checked the output voltages on it? Schematics are pretty much not available since none of these companies support the repair of their devices. — oldturkey03
@oldturkey03 - Without this bit of info I would have agreed!

> Then it starts up with fans at max speed

> Then I keep pushed the power button to turn off

> Then I push power button and it starts up with fans at max speed

These tell me the power is getting to the logic board, so its something deeper within it. Measuring the logic board rails would be a good direction but without having schematics and board views it will be difficult. — Dan
POSEIDONE MERCEDES your Logic Board should be a 820-2784-A Schematics and boardviews for that are readily available from the right places. — oldturkey03

score 0 · Answer 1 · 2020-10-25T05:31:21-07:00

Given your symptoms I think you’ve proved your issue is not the power supply. I don’t generally dig into the logic board as it’s not documented and its difficult to test on its own.

Instead, I rely on Apples diagnostic processes. So to start with here’s the Apple writeup on the onboard diagnostics:

Here's a breakdown of the onboard diagnostic LED's:

LED 1 - Indicates that the trickle voltage from the power supply is detected by the main logic board. This LED will remain ON while the iMac is connected to the AC power. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power is disconnected or the power supply is faulty.
LED 2 - Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.
LED 3 - Indicates that the computer and the video card are communicating. This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.
LED 4 - Indicates that the computer and the LCD display panel are communicating. This LED will be ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.

And here’s the published process

diags.pdf

So where does that leave us??

I’m suspecting your GPU board is shorted out as the most probable iMac Intel 21.5" EMC 2389 GPU Card Replacement

iMac Intel 21.5" EMC 2389

Psu DELTA ADP-200DFB / Logic Board voltages on iMac Intel A1311

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