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16" Macbook Pro USB-C ports keep getting fried

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
Hello friends- I have an interesting problem and I want someones opinion on it-

I had a higher end MBPro 16" i9/1TB/16GB/5500 model that I was using regularly with my external monitor connected directly via USB-C cable. After 2 months of use, the USB-C ports on the left side of the MBPro (same side I was using the monitor USB C connected to) died. The ports stopped recognizing the USB C connection from the monitor, and stopped any USB-C devices connected, including the Macbook Apple charger.

Last week, I was able to replace that model with a new MBPro 16" (same specs as previous), and started using on same monitor 2 days ago. After 1 day of monitor use, again the USB-C ports on the left side of the MBPro have now died. They no longer recognize the monitor or any other USB-C devices I plug into the left side, but they recognize the Apple charger so the macbook pro can still accept charge.

I have tried SMC Reset, Safe Mode, PVRAM,NVRAM, everything.

Is it the monitor causing my problem? Is the USB-C connection from the monitor somehow messing up the internal logic board usb-c bus by charging less or something?

Specifically, should I not use USB-C cable with it to connect to macbook pro now anymore? What's the alternative if someone can link me a better cable/dongle/product to connect to the monitor? Idk what to do anymore and this is very frustrating. Monitor I use is Samsung 43" CJ890 UltraWide display.
 

ght56

macrumors 6502a
Aug 31, 2020
529
361
This suggests something is wrong with either the monitor or the cable. What cable are you using to connect to the MacBook Pro? Were you using the monitor's power supply to charge the MacBook Pro?
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
This suggests something is wrong with either the monitor or the cable. What cable are you using to connect to the MacBook Pro? Were you using the monitor's power supply to charge the MacBook Pro?
I was using a USB-C cable that came with the monitor to connect to macbook pro. Yes, it would simultaneously charge the macbook pro when connected to the screen
 

ght56

macrumors 6502a
Aug 31, 2020
529
361
Something with the display or cable is potentially damaging the MacBook Pro (or potentially sending the ports into some sort of safe mode???)...it just seems extremely unlikely that you would get two MBPs in a row with the identical defect, and that defect would only appear when using that cable and that display. I was not able to find how many watts your display delivers, but my best guess is that it is well-short of the wattage that the MacBook Pro 16 needs, as there are only a hand full of displays feeding the type of wattage over USB-C the 16-inch needs. Even the LG UltraFine 5K does not, and Apple advices use of the OEM 96 watt charger.

If you perform Apple Diagnostics, (D at startup), does anything come back as failing?
If you use a USB-C-->HDMI cable with the display, do the problematic ports still work?

If I was in your situation, I would be extremely hesitant to use the cable and the display given one of them is likely problematic. If the display is in the return window, I would return it. If not, I would either try to RMA it or at least purchase a different cable, but never use the display to power the MacBook Pro and always use the full 96 watt Apple charger. My USB-C QHD displays supply 90W of charging power and I still use the OEM charger...I always plug the OEM 96 watt charger in first so that at no point is the system ever drawing power from the display. The only way I would ever use a display or hub to power my MacBook Pro is if it delivered the full 96 watts and if I was using a cable that was either sold by Apple and/or USB-IF Certified (or Intel Certified if TB3.) While the 16 inch MacBook Pro can use a lower wattage power supply, I am of the firm belief that this is a terrible idea in the long-term.
 
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macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
Something with the display or cable is potentially damaging the MacBook Pro (or potentially sending the ports into some sort of safe mode???)...it just seems extremely unlikely that you would get two MBPs in a row with the identical defect, and that defect would only appear when using that cable and that display. I was not able to find how many watts your display delivers, but my best guess is that it is well-short of the wattage that the MacBook Pro 16 needs, as there are only a hand full of displays feeding the type of wattage over USB-C the 16-inch needs. Even the LG UltraFine 5K does not, and Apple advices use of the OEM 96 watt charger.

If you perform Apple Diagnostics, (D at startup), does anything come back as failing?
If you use a USB-C-->HDMI cable with the display, do the problematic ports still work?

If I was in your situation, I would be extremely hesitant to use the cable and the display given one of them is likely problematic. If the display is in the return window, I would return it. If not, I would either try to RMA it or at least purchase a different cable, but never use the display to power the MacBook Pro and always use the full 96 watt Apple charger. My USB-C QHD displays supply 90W of charging power and I still use the OEM charger...I always plug the OEM 96 watt charger in first so that at no point is the system ever drawing power from the display. The only way I would ever use a display or hub to power my MacBook Pro is if it delivered the full 96 watts and if I was using a cable that was either sold by Apple and/or USB-IF Certified (or Intel Certified if TB3.) While the 16 inch MacBook Pro can use a lower wattage power supply, I am of the firm belief that this is a terrible idea in the long-term.

You think it could be the monitor itself? I was thinking using the USBC to connect with the monitor could cause it, but it could be fixed by using HDMI or Displayport cables since those dont supply power to the macbook, and therefore shouldn't cause any issues right? I don't have any other cables other than USBC so I haven't been able to try.

How can I perform apple diagnostics, haven't tried doing that?

Unfortunately the display is long out of return window. Once I get my new macbook pro and send this one back, what connection setup would you recommend for me? Should I use some sort of hdmi dongle, get a usb hub, or something else?
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
Something with the display or cable is potentially damaging the MacBook Pro (or potentially sending the ports into some sort of safe mode???)...it just seems extremely unlikely that you would get two MBPs in a row with the identical defect, and that defect would only appear when using that cable and that display. I was not able to find how many watts your display delivers, but my best guess is that it is well-short of the wattage that the MacBook Pro 16 needs, as there are only a hand full of displays feeding the type of wattage over USB-C the 16-inch needs. Even the LG UltraFine 5K does not, and Apple advices use of the OEM 96 watt charger.

If you perform Apple Diagnostics, (D at startup), does anything come back as failing?
If you use a USB-C-->HDMI cable with the display, do the problematic ports still work?

If I was in your situation, I would be extremely hesitant to use the cable and the display given one of them is likely problematic. If the display is in the return window, I would return it. If not, I would either try to RMA it or at least purchase a different cable, but never use the display to power the MacBook Pro and always use the full 96 watt Apple charger. My USB-C QHD displays supply 90W of charging power and I still use the OEM charger...I always plug the OEM 96 watt charger in first so that at no point is the system ever drawing power from the display. The only way I would ever use a display or hub to power my MacBook Pro is if it delivered the full 96 watts and if I was using a cable that was either sold by Apple and/or USB-IF Certified (or Intel Certified if TB3.) While the 16 inch MacBook Pro can use a lower wattage power supply, I am of the firm belief that this is a terrible idea in the long-term.
It says on the monitor website "The USB Type-C ports have a power output of up to 100W to provide juice to a variety of compatible devices." Is this good?
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
Something with the display or cable is potentially damaging the MacBook Pro (or potentially sending the ports into some sort of safe mode???)...it just seems extremely unlikely that you would get two MBPs in a row with the identical defect, and that defect would only appear when using that cable and that display. I was not able to find how many watts your display delivers, but my best guess is that it is well-short of the wattage that the MacBook Pro 16 needs, as there are only a hand full of displays feeding the type of wattage over USB-C the 16-inch needs. Even the LG UltraFine 5K does not, and Apple advices use of the OEM 96 watt charger.

If you perform Apple Diagnostics, (D at startup), does anything come back as failing?
If you use a USB-C-->HDMI cable with the display, do the problematic ports still work?

If I was in your situation, I would be extremely hesitant to use the cable and the display given one of them is likely problematic. If the display is in the return window, I would return it. If not, I would either try to RMA it or at least purchase a different cable, but never use the display to power the MacBook Pro and always use the full 96 watt Apple charger. My USB-C QHD displays supply 90W of charging power and I still use the OEM charger...I always plug the OEM 96 watt charger in first so that at no point is the system ever drawing power from the display. The only way I would ever use a display or hub to power my MacBook Pro is if it delivered the full 96 watts and if I was using a cable that was either sold by Apple and/or USB-IF Certified (or Intel Certified if TB3.) While the 16 inch MacBook Pro can use a lower wattage power supply, I am of the firm belief that this is a terrible idea in the long-term.
Just did a diagnostics, and got code ADP000, no issues found.
 

retta283

macrumors 68020
Jun 8, 2018
2,193
2,002
Victoria, British Columbia
Your cable might be defective, possible short-out of the ports but I don't know the technical lingo on this one. Replace the cable first, if still issues then try another monitor.
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
Your cable might be defective, possible short-out of the ports but I don't know the technical lingo on this one. Replace the cable first, if still issues then try another monitor.
After I get my laptop replaced with another macbook pro, I am thinking of replacing the cable with this Moshi USBC to Displayport cable. Is this a good option, or is using a dongle or hub better?

How do I know if its a cable vs monitor issue? I am hoping its a cable problem, because I can't afford to keep changing macbook pros whenever the ports go out.
 

retta283

macrumors 68020
Jun 8, 2018
2,193
2,002
Victoria, British Columbia
After I get my laptop replaced with another macbook pro, I am thinking of replacing the cable with this Moshi USBC to Displayport cable. Is this a good option, or is using a dongle or hub better?

How do I know if its a cable vs monitor issue? I am hoping its a cable problem, because I can't afford to keep changing macbook pros whenever the ports go out.
It'll be hard to say for sure until you replace the cable, as the monitor is running through that cable. Looks like that monitor has USB-C as well, so I'd just get a USB-C direct cable, but I imagine a USB C to Displayport will work as well. A hub will only complicate this further, so just stick with a cable for now.
 

ght56

macrumors 6502a
Aug 31, 2020
529
361
It says on the monitor website "The USB Type-C ports have a power output of up to 100W to provide juice to a variety of compatible devices." Is this good?

100 watts from a single port is sufficient provided that is a single port and not total for all devices. If that is a single port, my next question would be if the included cable supports 100W. That said, I would not personally use this display to charge the device at this point.

After I get my laptop replaced with another macbook pro, I am thinking of replacing the cable with this Moshi USBC to Displayport cable. Is this a good option, or is using a dongle or hub better?

This should work well, as you will then be doing power delivery from the OEM Apple charger. I feel this should eliminate the issue unless something is seriously wrong with the display. I would NOT personally use a USB-C cable from the computer to the display at this point, as I would not want the display sending power to the laptop at any given time.

How do I know if its a cable vs monitor issue? I am hoping its a cable problem, because I can't afford to keep changing macbook pros whenever the ports go out.

I don't have a great methodology for this, unfortunately, hence my caution with using either the cable or the display in the future. Someone with extensive USB experience may suggest measuring power draw using both the current cable and a new USB-C cable to see if there is an issue. However, most of the consumer devices I know of that do this will necessitate plugging into some device to draw power (i.e., whatever device you plug into may be at risk of damage.)

Someone with more knowledge on USB-C power delivery can correct me here if I am wrong.

I would definitely reach out to Samsung to see what they say on this topic and if they want to RMA the display.
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
100 watts from a single port is sufficient provided that is a single port and not total for all devices. If that is a single port, my next question would be if the included cable supports 100W. That said, I would not personally use this display to charge the device at this point.



This should work well, as you will then be doing power delivery from the OEM Apple charger. I feel this should eliminate the issue unless something is seriously wrong with the display. I would NOT personally use a USB-C cable from the computer to the display at this point, as I would not want the display sending power to the laptop at any given time.



I don't have a great methodology for this, unfortunately, hence my caution with using either the cable or the display in the future. Someone with extensive USB experience may suggest measuring power draw using both the current cable and a new USB-C cable to see if there is an issue. However, most of the consumer devices I know of that do this will necessitate plugging into some device to draw power (i.e., whatever device you plug into may be at risk of damage.)

Someone with more knowledge on USB-C power delivery can correct me here if I am wrong.

I would definitely reach out to Samsung to see what they say on this topic and if they want to RMA the display.
Thanks so much for this detailed response, this is super helpful! So basically when I get my next mbpro now, I plan to only use the displayport-USBC cable, and never USB-C cable again from now on.

The USB-C to USB-C cable that I was using came with the monitor itself, so I would think that it would be able to support the 100W right?

Theoretically, there shouldn't be any issues with using a displayport-USBC or HDMI-USBC cable with this monitor since those dont affect charging or power draw, right? I'm planning on using the dispayport-USBC on the left, and charger on the right once I get this laptop replaced.

I'll try to see if Samsung will do anything about it, but the display works great otherwise. This is just an interesting issue. I'm fine with foregoing the 1 cable setup and using a displayport-USBC if it will prevent any issue.
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
It'll be hard to say for sure until you replace the cable, as the monitor is running through that cable. Looks like that monitor has USB-C as well, so I'd just get a USB-C direct cable, but I imagine a USB C to Displayport will work as well. A hub will only complicate this further, so just stick with a cable for now.
Using a USB-C direct cable which came with the monitor is what created the issue in the first place, so that's why Im going to use the displayport-USBC cable when I get this laptop replaced. I just hope that this will not create any issues since the displayport cable doesnt charge the laptop, and that the issue isnt in the monitor itself doing something.
 

retta283

macrumors 68020
Jun 8, 2018
2,193
2,002
Victoria, British Columbia
Using a USB-C direct cable which came with the monitor is what created the issue in the first place, so that's why Im going to use the displayport-USBC cable when I get this laptop replaced. I just hope that this will not create any issues since the displayport cable doesnt charge the laptop, and that the issue isnt in the monitor itself doing something.
This is right, I didn't think of the power consumption problem, if Displayport still fries the ports then I'd say your monitor is bad.
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
This is right, I didn't think of the power consumption problem, if Displayport still fries the ports then I'd say your monitor is bad.
How can I know this without trying though? Could the monitor even do something through the displayport like that? I don't want to get the new mbpro, $50 displayport-USBC wire, and then have the ports fry after a few weeks or months again just to find this out.
 

retta283

macrumors 68020
Jun 8, 2018
2,193
2,002
Victoria, British Columbia
How can I know this without trying though? Could the monitor even do something through the displayport like that? I don't want to get the new mbpro, $50 displayport-USBC wire, and then have the ports fry after a few weeks or months again just to find this out.
I think it's highly unlikely that it would fry it, the only way I can really think to test would be to use it with another device you don't mind sacrificing to see if it kills it. This is not 100% but it would help narrow it down. You may be able to use a multimeter to see what it's putting out but it might be due to shorts, so that might not work either. It's a hard thing to diagnose without trial and error, unfortunately. I would talk to Samsung.
 

macbookfan21

macrumors member
Original poster
Aug 31, 2020
57
9
After doing some research, I have now found out that others have had the same issue, with the same monitor by using USB-C-USB-C cable:





So now this is a confirmed problem with this monitor when using USBC to USBC cable (same one that comes with the monitor). I just wonder if this can be prevented by using HDMI to USBC or DisplayPort to USBC...
 

crazy-trashcan

macrumors newbie
Jul 19, 2018
9
6
Hi, last month with two of our macbook pro's on both one usb-c port got fried with this monitor. We already tried changing the usb-c cables and switch from multiple macbooks. Without any effect. Some strange thing that i noticed is that we can't set the monitor to 120hz anymore. When switching to the 15W usb-c port, the option is available. Also charging the macbook with the usb-c cable connected to the 15W port is terrible, because when plugging an extra power adapter wont work...
 

duff_weird

macrumors newbie
Nov 26, 2020
1
0
I thought I was the only one! I had this same issue after I received my new MacBook 16” around April this year. Suddenly the usb-c ports on one side stopped working. Whilst on the phone to Apple Support, the second side stopped working. After 6 weeks having just about every major component replaced, it was working again, and then once plugged back into the this C43J890 monitor using the usb-c cable that came with it, it stopped working again, and actually started smoking whilst on the phone to Apple Support. Finally got a new replacement and have plugged it in with HDMI with no issues, but Samsung support were beyond useless. They couldn’t tell me what cable I can buy that should work, flat out denied it could be the monitor causing the problem, and wouldn’t help any further.
I’m now in a situation where I need to plug a third device into the monitor, but DO NOT want power delivered over USB-C. I have one device on DP, one on HDMI, and would love to know if anyone has experience using a cable that can use USB-C for display output only, without power.
 

crazy-trashcan

macrumors newbie
Jul 19, 2018
9
6
I think this is not possible. This should be controlled inside the display. But disabling the charging capabilities is not possible on this monitor...
 
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