Precision 3620 MT System Board Failure / Replacement

Question

Hey Folks,

This morning my Dell Precision 3620 MT is giving me an amber 2-1 pattern on the power button. According to this resource my motherboard is dead:

https://www.dell.com/support/manuals/en-us/precision-t3620-workstation/prec_t3620_om_pub/power-led-diagnostics?guid=guid-52106768-c0ec-411e-a583-375a950df672

The motherboard P/N is 0MWYPT (from the label under the circled 'Dell' on the motherboard). I see some available used boards with this part number (ebay, etc.). I also see some available boards with P/N 09WH54 that claim they are interchangeable.

My questions are:

1) Am I correct in diagnosing the motherboard as the issue?

2) Is 09WH54 a valid replacement for 0MWYPT? (My system has the M.2 PCIe NVMe and a Xeon E3-1240 v5)

3) What should I check to ensure this doesn't happen again? Should I check the voltage on the PSU?

Thanks for reading - any advice is welcome!

FrugalFarmer · Accepted Answer

Hey Folks,

I sorted out my issue from this morning and thought I would add the (embarrassing) solution here in case anyone else encounters it.

I recently purchased a USB mechanical keyboard with an internal USB hub. It has 2 USB connections (both 3.0, I found, when I RTM). I hot-swapped the keyboard. After a power-cycle (this morning), I encountered the "system board failure" diagnostic issue.

Later, I pulled the USB cables out and the computer booted (immediately, with no further action on my part).

I had plugged the keyboard USB cable into a USB 2.0 port and the hub USB cable into a USB 3.0 port. Any combination that is not both USB 3.0 ports causes the "system board failure" diagnostic on my T3620 and prevents the system from booting.

I hope this saves someone some time.

Cheers

mazzinia_ · Answer

That's a definitely weird issue, aside that i would have expected the kb to use a single cable to handle both the kb and the hub

bradthetechnut · Answer

Hi @FrugalFarmer,

Was anything plugged into the USB hub on the keyboard? Reason I asked is in case it affected diagnosis.

Typically, keyboard hubs can handle small things like mouse dongles, but not flash drives. Plug a flash drive into my keyboard and an onscreen warning pops up - not enough power. Yours could be different since it has a separate cable for the hub.

Ian.T · Answer

Could this then indicate the mother board or power supply cannot do its job, and it is unable to provide enough power to cope with the latest USB tech an able to use all USB ports being used at once. I have a new Precision 3650 and i too have a mechanical keyboard with 2 USB port Hub. But nothing plugged into the Hub and i got the same issue.
If this is the case I will regret going back to Dell desktop.

bradthetechnut · Answer

Hi @mazzinia

If it's a single wire kb like mine with a hub, there isn't enough power for both flash drives and kb. Flash drives sure do take some power.

I haven't heard of a separate wire on a kb for a USB hub before either. The catch is even with a hub, it's just one flash drive at a time that I know of due to power consumption.

Dell monitors with USB hubs use a separate wire, but also provide USB power seen as they're plugged into an outlet. So on a monitor with 2 USB's on the side, both can be used at the same time.

mazzinia_ · Answer

@bradthetechnut  I think it depends on the design and if the psu started to have some small quirks on some power lines, too. I'm using a small 4 ports hub plugged fix , with 4 flash drives always powered and no external power without issues

bradthetechnut · Answer

@mazzinia  Interesting, in a good way. With the 3620 being introduced in 2016, I think your theory of PSU trouble on some rails is quite possible.

mazzinia_ · Answer

@bradthetechnut I've always had a very reliable method to find out if a psu started to fail... the older kvm (passively powered) connected to it would start to display erratic issues with the kb/mouse ( ps/2 kvm ) and with its leds.

It was a very quick ( and early ) diagnosing involuntary tool, it always caught issues weeks before they could turn serious enough to show openly

FrugalFarmer · Answer

In my case, the keyboard docs clearly stated to use USB 3.0 ports. When I did so, it all worked fine - I just didn't read the docs until I had an issue.

The confusing part was that the Dell diagnostic when the computer refused to boot indicated a bad power supply.

I've had no issue with the power supply, and it has been a number of weeks since my initial post.

Cheers!

FrugalFarmer · Answer

No, there was nothing plugged into the hub.

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Precision 3620 MT System Board Failure / Replacement

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