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当前版本: Rob ,

标题:

iMac 20" A1174 dead, but +/-12VDC at PSU

文本:

Hi All !!!

Got an iMAC Model# A1174.  2006.  20" display.  Last 4 of the SN are VU2S.

When you press the power button, NOTHING happens.

Disassembled the unit.  What I discovered is: Power button tests good.  If I DISCONNECT the multipin connector on the motherboard (logicboard?), then plug the power cord in, I hear the HDD spin up.  No fans nor LEDs, just the HDD.  if I re-connect the multipin connector on the motherboard, then plug the power cable in, nothing.  Press the power button and again nothing.

Measurements:

With system normaled up but display and multipin connector removed I have the following on the PSU :

Grey wire 1 = +12VDC

Grey wire 2 = -12VDC

If I re-connect that multipin connector back into the motherboard, I get 0 VDC on those grey wires.  With the multipin connector disconnected and the power cable plugged in, I can read various DC voltages (5, 3, & 12).

I have a bad feeling that the problem is possibly with the motherboard since the multipin connector has all the appropriate voltages on it before I plug it back into the motherboard.

Any ideas of how to test the PSU any further, or how to isolate this problem better?

THANKS ALL in advance!

Rob

[image|772676]

设备:

iMac Intel 20" EMC 2105 and 2118

状态:

open

已接受的回答:

+302217

编辑: Jeff Suovanen ,

标题:

iMac 20" A1174 dead, but +/-12VDC at PSU

文本:

Hi All !!!
Got an iMAC Model# A1174. 2006. 20" display. Last 4 of the SN are VU2S.
When you press the power button, NOTHING happens.
Disassembled the unit. What I discovered is: Power button tests good. If I DISCONNECT the multipin connector on the motherboard (logicboard?), then plug the power cord in, I hear the HDD spin up. No fans nor LEDs, just the HDD. if I re-connect the multipin connector on the motherboard, then plug the power cable in, nothing. Press the power button and again nothing.
Measurements:
With system normaled up but display and multipin connector removed I have the following on the PSU :
Grey wire 1 = +12VDC
Grey wire 2 = -12VDC
If I re-connect that multipin connector back into the motherboard, I get 0 VDC on those grey wires. With the multipin connector disconnected and the power cable plugged in, I can read various DC voltages (5, 3, & 12).
I have a bad feeling that the problem is possibly with the motherboard since the multipin connector has all the appropriate voltages on it before I plug it back into the motherboard.
Any ideas of how to test the PSU any further, or how to isolate this problem better?
THANKS ALL in advance!
-Rob
+Rob
+
[image|772676]

设备:

-2006 iMac Model A1174 20" last4 of SN=VU2S
+iMac Intel 20" EMC 2105 and 2118

状态:

open

编辑: Rob ,

标题:

iMac 20" A1174 dead, but +/-12VDC at PSU

文本:

Hi All !!!
Got an iMAC Model# A1174. 2006. 20" display. Last 4 of the SN are VU2S.
When you press the power button, NOTHING happens.
Disassembled the unit. What I discovered is: Power button tests good. If I DISCONNECT the multipin connector on the motherboard (logicboard?), then plug the power cord in, I hear the HDD spin up. No fans nor LEDs, just the HDD. if I re-connect the multipin connector on the motherboard, then plug the power cable in, nothing. Press the power button and again nothing.
Measurements:
With system normaled up but display and multipin connector removed I have the following on the PSU :
Grey wire 1 = +12VDC
Grey wire 2 = -12VDC
If I re-connect that multipin connector back into the motherboard, I get 0 VDC on those grey wires. With the multipin connector disconnected and the power cable plugged in, I can read various DC voltages (5, 3, & 12).
I have a bad feeling that the problem is possibly with the motherboard since the multipin connector has all the appropriate voltages on it before I plug it back into the motherboard.
Any ideas of how to test the PSU any further, or how to isolate this problem better?
THANKS ALL in advance!
-Rob
+Rob
+[image|772676]

设备:

2006 iMac Model A1174  20" last4 of SN=VU2S

状态:

open

编辑: Rob ,

标题:

iMac 20" A1174 dead, but +/-12VDC at PSU

文本:

Hi All !!!
Got an iMAC Model# A1174. 2006. 20" display. Last 4 of the SN are VU2S.
When you press the power button, NOTHING happens.
Disassembled the unit. What I discovered is: Power button tests good. If I DISCONNECT the multipin connector on the motherboard (logicboard?), then plug the power cord in, I hear the HDD spin up. No fans nor LEDs, just the HDD. if I re-connect the multipin connector on the motherboard, then plug the power cable in, nothing. Press the power button and again nothing.
Measurements:
-With system normaled up but display removed I have the following on the PSU :
+With system normaled up but display and multipin connector removed I have the following on the PSU :
Grey wire 1 = +12VDC
Grey wire 2 = -12VDC
If I re-connect that multipin connector back into the motherboard, I get 0 VDC on those grey wires. With the multipin connector disconnected and the power cable plugged in, I can read various DC voltages (5, 3, & 12).
I have a bad feeling that the problem is possibly with the motherboard since the multipin connector has all the appropriate voltages on it before I plug it back into the motherboard.
Any ideas of how to test the PSU any further, or how to isolate this problem better?
THANKS ALL in advance!
Rob

设备:

2006 iMac Model A1174  20" last4 of SN=VU2S

状态:

open

原帖由: Rob ,

标题:

iMac 20" A1174 dead, but +/-12VDC at PSU

文本:

Hi All !!!

Got an iMAC Model# A1174.  2006.  20" display.  Last 4 of the SN are VU2S.

When you press the power button, NOTHING happens.

Disassembled the unit.  What I discovered is: Power button tests good.  If I DISCONNECT the multipin connector on the motherboard (logicboard?), then plug the power cord in, I hear the HDD spin up.  No fans nor LEDs, just the HDD.  if I re-connect the multipin connector on the motherboard, then plug the power cable in, nothing.  Press the power button and again nothing.

Measurements:

With system normaled up but display removed I have the following on the PSU :

Grey wire 1 = +12VDC

Grey wire 2 = -12VDC

If I re-connect that multipin connector back into the motherboard, I get 0 VDC on those grey wires.  With the multipin connector disconnected and the power cable plugged in, I can read various DC voltages (5, 3, & 12).

I have a bad feeling that the problem is possibly with the motherboard since the multipin connector has all the appropriate voltages on it before I plug it back into the motherboard.

Any ideas of how to test the PSU any further, or how to isolate this problem better?

THANKS ALL in advance!

Rob

设备:

2006 iMac Model A1174  20" last4 of SN=VU2S

状态:

open