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HP Recommended
HP Z620

HP Z620 Workstation will not POST. I get a SOLID BLUE led briefly, fans spin up, and then it powers off. Repeats.

 

From https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/hp-z820-turns-on-a... it sounds like it might a short fault protection.

 

Verified in other systems:

Processor OK

RAM OK

PSU OK

 

If I disconnect the 8-pin EPS - the motherboard gives me SOLID BLUE BLINK and then 4 x  RED BLINK => PSU error, so the motherboard seems to be working?

 

With the 8-pin EPS connected I get the ON / OFF cycle.

 

If I disconnect the power cord,(only way to turn off system) I get a SOLID BLUE, followed by either 2 or 3 RED BLINKS. This means CPU issue so I reseat the CPU multiple times and even verified it in another system. Also tried a known working CPU.

 

At this point, I'm thinking of trying the Crisis Recovery Jumper https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Crisis-Recovery-Ju... but don't think it will work since it seems to be a short of some kind and the system wont stay powered on - unless the 8-pin EPS is disconnected. Going to try testing for shorts on the EPS connector..

1 ACCEPTED SOLUTION

Accepted Solutions
HP Recommended

Fixed it!

 

Was a blown cap causing a short.

 

Followed the same process described in this video about a short circuit repair on a Macbook Air: https://www.youtube.com/watch?v=hFA4sHIXG8s

 

 

View solution in original post

https://tinyurl.com/rossmatrix Let's get Right to Repair passed! https://gofund.me/1cba2545 👉 If our videos have added revenue to your business, consider becoming a patron 🔵 Patreon https://www.patreon.com/rossmanngroup 🔵 We fix Macbooks & offer free estimates. https://rossmanngroup.com 🔵 Sen...
17 REPLIES 17
HP Recommended

Tried some differential diagnosis..

 

With only the front half of the EPS connected - 4 pins closest to the front - system stays on and I get 4 RED blinks = > PSU error.

Any time I connect any of the back two +12V, I get the ON / OFF cycle. So I guess the motherboard has a fault somewhere on that rail 😞

 

Anyone have a trace of the two +12V rails? Hoping its a blown capacitor that can be easily replaced.

HP Recommended

please search this forum for a post from "SDH" on how to recover a corupted bios

 

based on your description, it appears the bios is corupted and needs to be restored using the factory bios recovery steps

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With all 8-pin EPS and without the CPU in the socket => No BLUE led and 3 RED blinks.

 

Looks like a short on the CPU socket.

 

The BIOS maybe corrupt but I still have to solve the short. I don't see any bent/missing pins - blew it out with compressed air.

 

 

HP Recommended

i would try reseating/replacing the existing cpu if The Diagnostic LED blinks red 3 times and the system beeps 3 times (once per second), then a 2-second pause follows:

This indicates that the processor is not installed. or defective or the cpu sockek may have bent pins, or the motherboard is bad

you can get a low spec cpu off ebay quite cheaply

 

 

https://static.bhphotovideo.com/lit_files/84998.pdf

HP Recommended

Verfiied the CPU works in another system.

 

Cleaned it with compressed air and still same issue.

 

Here's a picture of the socket. I don't see any bent/damaged pins, maybe another pair of eyes will help.

 

z620 socketz620 socket

 

Probably will try to get a replacement motherboard in the meantime.

HP Recommended

Fixed it!

 

Was a blown cap causing a short.

 

Followed the same process described in this video about a short circuit repair on a Macbook Air: https://www.youtube.com/watch?v=hFA4sHIXG8s

 

 

https://tinyurl.com/rossmatrix Let's get Right to Repair passed! https://gofund.me/1cba2545 👉 If our videos have added revenue to your business, consider becoming a patron 🔵 Patreon https://www.patreon.com/rossmanngroup 🔵 We fix Macbooks & offer free estimates. https://rossmanngroup.com 🔵 Sen...
HP Recommended

Hello,

 

Please can you tell where was this capacitor located ?
I have the same on - off problem. The computer will turn on without booting then off then on again endlessly.

 

Thank you !

HP Recommended

there is no guarantee  that the previous posters bad cap will be in the same location as yours

 

also you have not said what exactly is happening with your board/boot sequence, please describe what happens EXACTLY when you power on your system

HP Recommended

Yes I know that there is no guarantee that it's the same cap even the same problem.
But it could be a clue.

 

I press the power button and the computer will try to boot, fan spin for 2 seconds and then it shuts off. Then it turns on again and shuts off the same way. I can loop like this forever. Same as described by OP or here https://forums.servethehome.com/index.php?threads/hp-z620-wont-post-powers-on-and-off-quickly.23300/ .

 

If I disconnect the 8pin EPS it beeps and flashes red 4 times.
With the 8-pin EPS connected I get the ON / OFF cycle.

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