Z800 possible CPU heatsink problem

[LTre]

Hi,

I've got an old Z800 booting with the LED going RED straightaway with the LED blincking 2 x times, once every second, followed by a two-second pause. Two beeps etc.... According the to doc this is a CPU thermal issue. I've checked all of the fans and re-selled the heatsink with new pastes with no success. How can I check if the issue is really on the CPU heatsink and not on the CPU itself or the motherboard? Can I disable the heatsink check just to see if the workstation starts anyway?

Thanks.

[DGroves]

no, removing the sink and powering the cpu will result in a thermal shutdown right away

to test proper contact, remove heatsink and clean sink/cpu, then apply small install pea sized drop to top of cpu and  reinstall heatsink

now remove heatsink and look at bottom of heatsink,....... entire bottom should be evenly covered 

[LTre]

Hi,

Thanks for the quick reply. 

I checked the bottom of the heatsink and the top of the CPU and they are both well covered by the new heatsink paste.

Do you know how the computer detect the heatsink issue. Is it via the heatsink itself or via the CPU. If this is via the heatsink, is there a way to temporarily trick the computer by moving a jumper on the motherboard or putting a "fake" rewired connector on the heatsink motherboard connector so he think that everything is fine? Basically I'd like to know if the issue is the CPU, the heatsink or the motherboad before I'll try to buy spare parts as they are quite expensive.

Thanks

[DGroves]

hmmmm,.......................

your not thinking clearly are you?

"Do you know how the computer detect the heatsink issue. Is it via the heatsink itself or via the CPU"

see any wires or connections.contacts on them there heatsinks? no? neither do i  so obviously...............................

the cpu on the other hand has been documented in thousands of articles (google is your friend) as having thermal sensors which the motherboard reads and responds to

i'm going to ask you to be very specific/detailed in regards to the error(s) you are getting and when they appear before i go off  looking at things i don't need to trying to help you so please repost what/when the problem or error happens

[LTre]

The 2 x CPU heatsinks are attached to the motherboard with 5 pins connectors but only 4 of those pins are in use. I believe the heatsinks are managed using the PWM and Tach pins.

The problem happen just after the workstation is powered.

3 or 4 seconds after the workstation is powered and the fans all start spinning the following happen:

- Red Power LED blinks two times, once every second, followed by a two-second pause. The workstation beep is in sync with the LED.

- This repeat itseft 5 time and then the beep stop and the LED blink red until I shutdown the workstation.

[DGroves]

first of all the z800 as two different heatsinks 

the stock low power cpu one

463981-001 or 463990-001 (uses a normal 4 pin, 5th is empty) 80 watts or lower

and the high power cpu one 90 watts to 120 (for 130 watt cpu's hp had a water cooling option)

High Performance Heatsink Fan 463991-001

the high performance unit is the one that uses the 5 pin connector

if you have the wrong heatsink or the heatsink fan lead not connected correctly, or the fan shrouding missing it will have thermal issues

read the post in green from "SDH"

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Z400-heatsink-fan-...

[LTre · Accepted solution]

It was a faulty heatsink.

I tried to reboot the workstation with only one CPU and one heatsink, permuting between the 2 sets and I found the culprit.

So I think I was thinking clearly after all.

Thanks anyway.