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Post failure with cpu power lead plugged in

pettytheft
Level 7
System:
ASUS RAMPAGE V EXTREME, Extended ATX x99 Motherboard , LGA 2011-V3 Socket, DDR4 3300Mhz+(OC)
Intel Core i7-5960X Haswell-E 8-Core 3.0GHz LGA 2011-v3 140W Desktop Processor BX80648I75960X
Two EVGA GTX 970 4GB GDDR5 256bit, DVI-I, DVI-D, HDMI, DP SLI Ready Graphics Card (04G-P4-1970-KR)
Corsair DOMINATOR PLATINUM 32GB(4x8GB) DDR4 2666 (PC4-21300) C15 Desktop Memory kit
Cooler Master Ultimate UCP – 1100 Watt power supply
Cooling fluid: Thermaltake c1000 white

History and description of problem:
Prior to moving from west coast to east coast removed hard drives, memory cards, graphics cards, CPU power lead and main motherboard lead and drained cooling fluid.

Upon reassembly, refilled fluid reservoir, plugged in main power lead to motherboard and turned on computer to push fluid along the lines. (CPU power lead still unplugged). All fans were working and fluid moved, perhaps rather slowly. Noticed a kink in one section of the line and partially corrected this using a plastic clamp. Fluid did flow better. Still had a couple of large bubbles and also noticed that the fluid had many pinpoint black dots (mold?). Did this several times, turning off computer, tilting case back and forth, trying to eliminate bubbles in the lines, and then turning computer back on. When cooling system appeared ready, plugged 8-pin CPU power lead back in. Computer posted as expected (without monitor, keyboard, hard drives).

Turned computer off and let it sit overnight. Next morning noticed minor fluid leakage along the seam between the copper layer and main body of the heat sink. Seemed to have dripped straight down to bottom of case without contacting CPU or motherboard. Unplugged power leads, tightened the heat sink with an Allen wrench and re-mounted the heat sink to the CPU.

Plugged both power leads back in (main 24-pin and CPU 8-pin). Computer turned on and then immediately turned off, briefly displaying code 00. Repeats this every time the CPU power lead is plugged in. When unplugged, using only main 24-pin power connector, all systems seem powered, e.g., fans, ram led lights, fluid pump, etc.

Thought that CPU could be poorly seated, heat sink over-tightened or motherboard CPU socket had bent pins. Checked carefully, reseating CPU and heat sink, removed and reinstalled CMOS battery, reset CMOS, switched BIOS. System continues in infinite post loop when CPU power lead is plugged in.
I have not tried to flash BIOS yet or operate the MB out of the case, which I will do next.

Thoughts, suggestions on how to proceed?

Thank you very much,
c & m
1,939 Views
2 REPLIES 2

jab383
Level 13
Hi, Pettytheft and welcome

The 24-pin and 8-pin CPU power cables provide one important function even when the PC is not running. They keep the motherboard grounded through the PSU to the case. That greatly reduces the chance for static electricity damage. Try to keep at least one of those connected whenever the motherboard is in the case, connected to anything else, or when you are handling it.

The equipment list doesn't include the CPU cooler. What make and model?

You already did most of the checklist with the reseating and clearing CMOS.

My strongest suspicion is that a voltage regulator, or perhaps the CPU, has a short circuit that shuts off the PSU as soon as POST starts. The VRMs are what the 8-pin cable powers. There are a few other things, too. The PSU might have a problem with the 12-volt rail that drives the 8-pin cable. Was the PSU under the dripping coolant?

My suggestion is to beg, borrow or steal (ref username) parts you can use to temporarily replace the suspected components. In order of increasing cost and complexity:
PSU
CPU
Motherboard
The permanent fix is to RMA the offending component.

pettytheft
Level 7
Hey thanks for the quick reply. I wish I could test the components but I moved to a remote region where no one has anything comparable to test it with for hundreds of miles. I found a computer tech that wants $110 an hour to do the same thing I’ve been doing—only they have never worked with a watercooled system so that seems a waste.

The CPU block is a XSPC Raystorm CPU Block for LGA 2011.

Yes. The power supply was under the dripping coolant--but the amount that leaked out was negligible and only came contact only with the bare metal side of the unit (drops, not a flood).

I have a 300w power supply I could try and run the board off of. Should I try that?

I read somewhere about a paperclip test to see if the power supply is working properly—is that applicable here? Also, to your point, I have two free dedicated 8 pin connectors running from the PSU and tried both—would that make a difference?