ryogadan78
Senior Member
Last Activity: Yesterday, 05:21 AM
Joined: 11-20-2021
Location: Messina
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What could be the next step in the diagnosis phase? -
iMac A1418 - No LED, no power after overvoltage on Ethernet port
Hi guys, I need your help again.
I have this iMac from a customer that shut down during a storm along with all the other devices in the house. In particular, the router, connected via Ethernet to the iMac, caught fire.
When I removed the screen from the iMac to check the status of the LEDs, I noticed that none of them were lit. I had a perfectly compatible and working power supply, so I tried it right away, but the problem remained the same (no LEDs). With the thermal camera, I noticed only a slight warming (32 degrees) of the NCP1605BG chip on the power supply. The rest was completely... -
Hi mon2, thanks for the suggestion. I too had noticed the input and output indications, but strangely I never saw any difference in reading the data. I attach photos taken today...
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Hi mon2, thanks as usual for your support. You are right, with original power adapter I read 20V on USBC port, but the main problem remain the same (doesn’t turn on)....
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I should add that using a tester on the micro USB connector I note that the input voltage detected is 5VLeave a comment:
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MacBook Pro 15" A1707 820-00281 turns on once in 10 (or maybe more)
I have this macbook that is behaving abnormally. Initially it had a battery life problem, after changing the battery everything seemed ok, but after about 5 days it started giving problems. It turns on once in 10 (or maybe more), more often after I unplug the battery connector and plug it back in. Sometimes after SMC reset. But it's not a stable rule. Visual inspection shows no problems, no signs of liquid contact or burning. Looking with the thermal camera I notice that the chip that heats up the most is U7220.
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It seems that my boardview is not exactly identical to my mainboard...
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Here are two photos, of the chip and what I see under the mainboard. Could I clean the mainboard a bit to find out if there is any more damage?...
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I don't want to bother you, just to know if you think I can go ahead with the repair or is it too complicated...Leave a comment:
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Hi Mon2, do I start disconnecting ICs and cleaning the mainboard?...Leave a comment:
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Hi Mon2, sorry I have not been present. Health problems. Here I am with you. I am enclosing a photo where you can see the initials above the chip and a photo showing a larger area of the mainboard. I actually noticed too that the boardview file does not match 100%.
The region of this area is burnt
Topside marking of IC
51486
TI OA8
AEP5...Leave a comment:
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Hi Mon2, I don't know if you have seen the latest updates, I need your help. I really wouldn't know how to go on...Leave a comment:
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I injected 1V on the 5V pin of one of the capacitors on which I detected a short to ground. With the thermal camera, I identified an area of the mainboard that I had not inspected and found this nice surprise. Based on the boardview IC it is PU8700. Any suggestions?...
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Done, the short circuit still seems to be present. Resistance to ground is 0.4ohm...
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Hi Mon2, I don't know if you saw my answer. Unfortunately I don't really know how to proceed considering that the VBUS comes to this IC. Any suggestions?Leave a comment:
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In the boardview, the USBC connector is marked as CNP1. The TBTA_VBUS_L pin is connected to pin 10 of an IC marked on the boardview as UP1. I enclose a photo pointing out that two nearby capacitors are shorted to ground on both pins...
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OK the procedure should not be complicated also because I caused the short on the only USBC port. I have to leave the lab now but I will do the research as soon as possible and update you...Leave a comment:
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Hi Mon2, you are always so kind to reply.
I only have the boardview of this board and probably wouldn't have the experience to read a schematic. Could you help me? identify the components to be tested by the name they have in the boardview?...Leave a comment:
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Omen laptop DA0G3EMBCD0, shor circuit from USB
Good morning guys. I have my Omen laptop (DA0G3EMBCD0) that now gives no signs of life (no LED).
During the night I misplugged a slim usbdrive which had the shield damaged, I guess I caused a short because the laptop turned off and never turned on again.
After taking it apart I noticed with the thermal imaging camera that two ICs on the mainboard reach 100 degrees Celsius. Thanks to the boardview I saw that they are PU8600 and PU8601. I tested the pins of these ICs and found these anomalies compared to the schematic
PU8600
6 (3VS5_LX) - 5 OHM to ground (normal?)... -
Good morning guys. I have my Omen laptop (DA0G3EMBCD0) that now gives no signs of life (no LED).
During the night I misplugged a slim usbdrive which had the shield damaged, I guess I caused a short because the laptop turned off and never turned on again.
After taking it apart I noticed with the thermal imaging camera that two ICs on the mainboard reach 100 degrees Celsius. Thanks to the boardview I saw that they are PU8600 and PU8601. I tested the pins of these ICs and found these anomalies compared to the schematic
PU8600
6 (3VS5_LX) - 5 OHM to ground (normal?)...Leave a comment:
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