farm setup 3-4 MB vrm pops

[Dinmaster]

im in a hurt here, i setup two systems out of 6 yesterday not a problem, bottom of the rack. then today i wired the rest very neatly etc. go to turn on the 3,4,5,6 and first one fire on the vrm under the heatsink next to cpu. 4th same place but caught it before it got bad, 5th i heard a pop but couldn't find anything, 6th a chip on the top of the mb burned a little. This sucks but things happen. i took pics of the mb setup and my pdu. you can see i have the mb's on aluminum standoffs 1" and its sitting on a piece of flashing. the pico ground in on the standoff cause its a round jack for pico power from a pcie cable. not sure what i need to do to fix this possible short? like i said i didnt have a problem with the two on the bottom but then 3-4,5-6 had problems... any help is good help.

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[Marvell1]

im in a hurt here, i setup two systems out of 6 yesterday not a problem, bottom of the rack. then today i wired the rest very neatly etc. go to turn on the 3,4,5,6 and first one fire on the vrm under the heatsink next to cpu. 4th same place but caught it before it got bad, 5th i heard a pop but couldn't find anything, 6th a chip on the top of the mb burned a little. This sucks but things happen. i took pics of the mb setup and my pdu. you can see i have the mb's on aluminum standoffs 1" and its sitting on a piece of flashing. the pico ground in on the standoff cause its a round jack for pico power from a pcie cable. not sure what i need to do to fix this possible short? like i said i didnt have a problem with the two on the bottom but then 3-4,5-6 had problems... any help is good help.

never had once board fry ,usually its the card that goes not the mother board.  Let alone 2 ? bad PICOs talk to ur vendor

wait a min WTF you need to put the boards on standoffs that are not conductable to the metal rig frame !!  I use pizza boxes to stand the mother boards on

Sorry but i find this kinda funny, Im suprised you didnt fry every single motherboard that was connected metal to metal to the frame !!

Is this the first PC you have ever put together ? most folks who build PC's learned the hardway when the short out a few boards learning that you need to ground yourself before event working on a board

you can do this by touching anything metal or the floor even if its not insulated

[mettalmag]

what PSU is this and how many rigs does it power if you can tell me

[Dinmaster]

these are picopsu 150w, connected to dps-2000bb 2000w psu 4kw(2 x 2000w psu together) unit connected to a ap7811 PDU. after spending most of the day looking and testing components i think it was from no ground points to the motherboards. since picopsu's don't have grounds in the atx connector like a normal psu. I was thinking the 2000w psu's would be grounded and them touching the tier shelving would ground mind you the bottom tier isnt touching the 4kw. I have an old system sitting around and will use it to test the tier shelving out, this time ill put the system on a piece of wood or cardboard to separate it but ill also ground the board at the screw to the PDU unit (common ground). unless im missing anything, as for metal etc ive had no issues in the past with it but i have always used a normal PSU and not a picopsu.

the 4kw can easily handle 4 systems of 6 cards, especially when its not mining. im running 6 systems with 2 x 4kw psu units 4-2. the burning occurred right when i power the system on.