Hi All,

Firstly I know very little about PC's! I use them but have never delved inside apart from to change a disk drive and that sort of thing. I do mess around a fair bit with embedded control and a bit of analogue electronics though.

I have a HP elite desk 800, has windows 10 on it. I bought it along with a robotic milking system, it has the management software for the cows on it and connects via ethernet to the robots.

It had been switched off for quite a while, a month maybe, when I tried to power on nothing much happens, the little led next to the switch lights but goes out as soon as the switch is released.

I assumed it was probably a power supply issue so bought and fitted a new one but still no joy.

I guess the next thing is the mother board? Question is how much can I change before this is no longer the pc I had (if that makes sense?!) I could buy a new desktop but I think the software will cost a small fortune so it's definitely worth trying to sort out this one!

Any suggestions gratefully received!

Thanks Geoff

 

It had been switched off for quite a while, a month maybe, when I tried to power on nothing much happens, the little led next to the switch lights but goes out as soon as the switch is released.
I assumed it was probably a power supply issue so bought and fitted a new one but still no joy.

Hi Geoff,
Does the laptop work if the power supply is plugged in?
It is possible that the internal battery is flat as a cow pat.
Plug in the power supply, don't switch On the PC for say about an hour, let the battery recharge a little.
After about an hour of charging, keep the power supply plugged in and switch On the PC, let us know the result.

Your milking program will be on the hard drive and should be recoverable, there are companies that offer a data recovery service.

E

 

Hi Eric,

Thanks,sorry I should of put it's a desktop so no battery except a little 2032 which I've changed. I do fear it might be dead? I'm just not sure how to tell!

Cheers Geoff

 

Hi Geoff,
I guess you have tried these repair video's???
E
Link:
https://www.youtube.com/results?search_query=+HP+elite+desk+800,+not+powering+up

https://www.youtube.com/results?search_query=+HP+elite+desk+800,+fault

 

Had already seen the first one, just watched a couple more! I've got a new power supply in it, there is a green light on the board but nothing else happens!

Cheers Geoff

 

There is a little yellow button on the board with CMOS written next to it I'm itching to press....

 

Hi,
Read this linked article, ref Yellow button

E
https://www.reddit.com/r/Hewlett_Packard/comments/g53nwi

Also;
https://www.google.com/search?client=firefox-b-d&q=hp+elitebook+800+onboard+yellow+button

 

Yellow button (page 118)

http://h10032.www1.hp.com/ctg/Manual/c04832374.pdf

 

Thanks, that's a bit of bedtime reading for me!
Pulled this bit out,
My power button looks to be on the system board, I'll pop the cover of it in the morning, I've already done the adapter, if I buy a new motherboard for it, will all my software run as it did? (the 5v_aux light is lit)

 

And the hard drive light doesn't come on...

 

Just looking at a new/refurbished motherboard, it looks like it comes without the processor on ? Assuming I put my processor on the new board?
Cheers Geoff

 

Hi Geoff,
I assume the Processor is a plug in type?
If yes, ensure the correct location of Pin #1
Your Cow program should be in the hard drive.

E

 

Thanks Eric
I'll order that then and see what happens!

 

It could be the hard drive is dead. When you power up, listen carefully to the hdd. If you hear repeated clicking noises from the drive, then it has died for some reason. you would have to restore from backups after replacing the drive.
Usually a failure of RAM or video shows up with a bios error message. But, try swapping the RAM modules around to rule that component out. The same happens for a disk drive failure, but sometimes it takes a couple of minutes before the system gives up on the drive and shows an error, usually “no boot device” or similar.
I doubt it is the motherboard itself, unless something got inside the box an produced corrosion, like water.

 

Update!
A bit of progress, I fitted the new motherboard, it beeps and the fans go which they didn't before but it flashes a ram error out in the front light.
3 red flashes, 2 white with some beeps, I've taken the ram cards out and put them back in but no joy so far, is the next step buy a couple new ram cards?

Cheers Geoff

 

I've put new ram cards in but still the same problem, there is a SSD on the board, could it be that?
Cheers Geoff

 

Tried them in different slots and it now starts up on the diagnostic page but won't boot up windows? The tests say the hard drive is ok? Should the windows boot live on the hard drive?
Is there any way to get it to boot and see if the cow program is still there?

Memory test says there is none installed on board? This was a second hand mother board I'm now getting a bit suspicious about how good it is!

 

Hi Geoff,
Is the HD a SATA or ATA type.?
I would suggest you ask a friend to temporarily install your drive into his PC as a second drive.
He could then verify the drive and its data.

E

 

Hi Eric,
Thanks I might do that it's a sata drive, I've got it running checks at the moment a so far all seems fine apart from it not being able to find somewhere to boot from?! There is a little SSD card on the motherboard, is there any chance the boot software might be on that? Might not be seated properly or something?

I've seen a similar computer with windows 10 on it for not much money, might it be worth a punt to put my hard drive in and see what happens?!

Cheers Geoff

 

Tried them in different slots and it now starts up on the diagnostic page but won't boot up windows? The tests say the hard drive is ok? Should the windows boot live on the hard drive?

BTW - a bad boot disk drive will show POST error on bootup "no boot device".

Is there any way to get it to boot and see if the cow program is still there?

Depends on the type of disk drive. If its NVME, then anything on the disk should still be there.

Memory test says there is none installed on board? This was a second hand mother board I'm now getting a bit suspicious about how good it is!

Did you transfer the memory strips from the old board to the new?

Can you post a photo of a top view motherboard installed in the PC?
Also, Can you post a photo of the diagnostic page?