Trying to repair a HP Z800 850W PSU by Delta

[Pepsi]

Re: Trying to repair a HP Z800 850W PSU by Delta

Mine has the same failure and it is absolutely dependant on the temperature. At a room temperature of approximately 18 degrees Celcius it will do the clicking on/off all the time.
If i take a hair blower to give it som heat while it is clicking, it starts to operate normally after about 30 seconds.

If i then raise the room temperature to 22 to 24 degrees it will go on "for ever".

Havent been able to identify the failing components yet.

[Behemot]

Re: Trying to repair a HP Z800 850W PSU by Delta

If it is indeed something with tracks/SMD, it is almost imposible to find with the number of SMD components in there.

This is actually the reason why most modern computer PSUs die. There is so many (SMD) components and when they have different kinds of protections, when one single component goes bad, it usually ends with some of the protections kicking in. That is why the problem often appears to be same throughout manufacturers and platforms, yet it could be totaly different thing. They just behave the same - do not turn-on at all, or turn on and shut down (protection kicking in).

[BLinux]

Re: Trying to repair a HP Z800 850W PSU by Delta

Mine has the same failure and it is absolutely dependant on the temperature. At a room temperature of approximately 18 degrees Celcius it will do the clicking on/off all the time.
If i take a hair blower to give it som heat while it is clicking, it starts to operate normally after about 30 seconds.

If i then raise the room temperature to 22 to 24 degrees it will go on "for ever".

Havent been able to identify the failing components yet.

My problem is not temperature dependent at all. It often fails all of a sudden after hours of use and is still warm. And then it refuses to power back on, but then a few days later starts to work again.

If it is indeed something with tracks/SMD, it is almost imposible to find with the number of SMD components in there.

This is actually the reason why most modern computer PSUs die. There is so many (SMD) components and when they have different kinds of protections, when one single component goes bad, it usually ends with some of the protections kicking in. That is why the problem often appears to be same throughout manufacturers and platforms, yet it could be totaly different thing. They just behave the same - do not turn-on at all, or turn on and shut down (protection kicking in).

yeah, i fear that this was going to get complicated to identify root cause. if the problem was straight forward, i would have been happy to repair it. I could spend hours trying to find root cause, or i could spend $100 or so and get another one which is what i've done for now. the economics of spending several hours on this just didn't make sense. i did try to find one that was of a newer revision in hopes that it lasts longer.

[Supman]

Re: Trying to repair a HP Z800 850W PSU by Delta

Looks like prices for these units have gone up... Does anyone have ideas for getting one for under 100USD?

[asusxxx]

Re: Trying to repair a HP Z800 850W PSU by Delta

Any schematic of this power supply?

[Behemot]

Re: Trying to repair a HP Z800 850W PSU by Delta

You can guess…

[Solution]

Re: Trying to repair a HP Z800 850W PSU by Delta

Hello,
I am confronted with the same problem. The prices for a used HP PSU here in europe start with 150USD. That's too much money for trash. A new one is over budget. So I was looking for alternative solutions. My plan now ist to build in a conventional PSU which will sit on top of the Z800 case. I found someone doing kind of the same thing. URL: http://andybrown.me.uk/2014/11/01/z800/
The text section “The power supply” describes it pretty accurate.

What is your opinion about this solution. Do you see any problems with this method?
Thx for any response!

Sorry for any spelling mistakes. Greetings from Germany

[Curious.George]

Re: Trying to repair a HP Z800 850W PSU by Delta

I am confronted with the same problem. The prices for a used HP PSU here in europe start with 150USD.

Ouch! I rescue (complete) Z800s for $10/ea. Lately, I've just been pulling the power supply and disk sleds and discarding the rest of the chassis (too damn big/heavy to stockpile them -- I've got 5 in service)

Have you tried surplus equipment auctions (larger businesses, universities, city/county governments)? I usually come across them in groups of two or three... then a lull before the next group appears (as business folks upgrade their department resources). Most folks (here) have no interest in such big/heavy machines so they just get scrapped (so, I buy them for their scrap value).

That's too much money for trash. A new one is over budget. So I was looking for alternative solutions. My plan now ist to build in a conventional PSU which will sit on top of the Z800 case. I found someone doing kind of the same thing. URL: http://andybrown.me.uk/2014/11/01/z800/
The text section “The power supply” describes it pretty accurate.

Are you running the 850 or 1100? (You'll need the 1100 if you use any of the power-hungry GPUs originally sold with the box -- I use Q6000s and Q5800s so can't get by with just the 850)

What is your opinion about this solution. Do you see any problems with this method?

Perhaps the length of wire harness? IIRC, there's already a fairly long harness INSIDE the chassis (or, maybe I'm thinking of the T7400s??). Unless you drill straight UP through the top of the case (from the power supply's mating connector), I can't see how you'll be able to increase this by anything less than 6-8 inches.

Do you have a particular "fondness"/reliance on the Z800? It's a decade old and you can easily find something smaller, faster (unless you need all the internal and "external" bays)... I see pretty capable i7's selling for $300.

(I've been stockpiling Z800 spares simply because I don't want to have to reinstall all my software on newer boxes -- it takes me several MONTHS to do that for each workstation. So, I'd rather just move the drives over to an "identical" box in the event of a failure instead of being "forced" to upgrade to a newer box -- and newer licenses, etc.)

[saeed_b53]

Re: Trying to repair a HP Z800 850W PSU by Delta

hello sir
you can help to me with dps-850dp schematic?
i need to know ic901 name
thank and regards

[Kenny_C]

Re: Trying to repair a HP Z800 850W PSU by Delta

Well today i replaces 1 of the capacitors that seemed like it could be bulging. i have the 1100 watt power supply. after much pain and agony i finally got that 1 capp replaced. it did not fix the problem. it was the the 25v 220uf one. but hey at least i haven't broken it worse. none of the capps looked that bad but looking at some they were completly flat and a few of the others were slightly raise a little more so i will continue to change out the capps untill i either fry the psu or fix it. but if i do fry it i intend to make a power supply that will fit inside the original case as the price of a new one is outside the realm of reality for me. i'd much rather get a newer model then spend the 300 buck, and a used one it out of the question as i don't care to purchase a ticking time bomb. kinda sadd to because i have been very impressed with this machine, even though it is now 2020.

[Solution]

Re: Trying to repair a HP Z800 850W PSU by Delta

Thx @Curious.George for the detailed answer!

I totally forgot my post here. So I will try to give an short update to my Z800 PSU story.
After weighing up the risks I gave it a try with a conventionel PSU. I bought a 850W PSU from the japanese company Thermaltake. Removed the origininal PSU and all cables. Detailed manual in the Link of my first post.
Now to the problem where to place the PSU. I tried to put the PSU in front of the case. It is attached on a metal plate wich is connected with the Z800 tower. It worked out very good for me and is running without problems since 6 months now.
See how it looks on the photo, maybe its an option for someone.

[sam_sam_sam]

Re: Trying to repair a HP Z800 850W PSU by Delta

See how it looks on the photo, maybe its an option for someone.

This is an interesting mod that you did to this computer but why did you put the switching power supply in the front of the computer ( why not in the back of the computer )

[spforster13]

Re: Trying to repair a HP Z800 850W PSU by Delta

Mine has the same failure and it is absolutely dependant on the temperature. At a room temperature of approximately 18 degrees Celcius it will do the clicking on/off all the time.
If i take a hair blower to give it som heat while it is clicking, it starts to operate normally after about 30 seconds.

If i then raise the room temperature to 22 to 24 degrees it will go on "for ever".

Havent been able to identify the failing components yet.

Pepsi,

Did you ever sort out the problem with the z800 PSU that was temperature dependant as I'm having that problem with my PSU. Any help on this matter would be greatly received.

Thanks
Simon

[Behemot]

Re: Trying to repair a HP Z800 850W PSU by Delta

What spot do you need to heat for it to work?

I've recenty read on another forums that even things like glass SMD diodes in the auxiliary stand-by transformer winding which actually do power the driving ICs do go bad. As well as the ICs themselves. However, often in a manner it all appears fine with a meter, yet replacing it solves the problem! So like go look for such problems

I wonder, what the problem could be, like some micro-crack in the material of the component when it behaves as such?

[spforster13]

Re: Trying to repair a HP Z800 850W PSU by Delta

Haven't tried heating any individual spots upon it, but we have needed to at time put in a low-temperature oven to warm it up a little. It's more of a case that it works on warmer days and not on cold days.

[qaziuzair]

Re: Trying to repair a HP Z800 850W PSU by Delta

I am having the same problem. The supply Works on Higher Tempratures but fails on Low Tempratures. Changed Almost all the Capacitors but the Issue is still there.

Does anybody successfully resolved this issue ?

One More Question , Does DELL T5700 PSU will work with this using 24Pin to 18 Pin Connector ?

[jreuter60]

Re: Trying to repair a HP Z800 850W PSU by Delta

My old trusty Z800 started randomly shutting off with no warning. I assumed power supply problems and found this thread. I visibly checked all the caps, cleaned out a ton of dust, etc., to no avail. I did not want to start changing parts willy-nilly without knowing the cause.

Then, quite by accident (thanks to almost getting burned) I discovered that the graphic card was extremely hot. Its fan was very stiff and barely turning, probably either from wear or accumulation of fine dust within. At some temp it seems the system gets shut off, so it appears there is some way for the OS or this graphics card (FirePro W5100) to kill system power without warning if the chipset gets to hot. On the perf monitor I saw it get over 90C, I suspect it probably killed the system around 100C.

I used some mounting tape to stick an external fan to the card, powered from a spare front chassis fan connector on the Z800 MB, and all is well.

[Behemot]

Re: Trying to repair a HP Z800 850W PSU by Delta

It its some cheap sleeve bearing fan, just disassemble, clean and lube the bearing, and it should run fine again.

[momaka]

Re: Trying to repair a HP Z800 850W PSU by Delta

It its some cheap sleeve bearing fan, just disassemble, clean and lube the bearing, and it should run fine again.

It is.
But many video cards made in the last 10 years have switched to -sealed- sleeve bearing fans, where the locking c-washer is installed at the front of the fan and permanently closed with plastic. After this, the fan rotor is popped in and locked in place by the c-washer, thus making it impossible to take apart... well nearly. If you try to use just brute force, you'll break the fan. The method I found to work is to drill holes on the back of the fan to expose the shaft. Then heat shaft with soldering iron to 130-150C, then try pulling rotor out. The heating of the shaft with the soldering iron basically is to soften/melt the locking washer, so when you pull it out, it breaks the locking washer. But it doesn't always work, as some c-washers are really hard to melt. Also, you risk damaging the rotor (the shaft pulling out of the plastic blade assembly) if you're not careful with how much heat you apply. But if the fan is completely stuck, you've got nothing to loose. Alternatively, after drilling the fan back, you can just try to put some oil on the shaft and hope that is enough to loosen the dirty sleeve bearing. But I find this fix doesn't last more than a year, whereas taking the fan apart and cleaning the sleeve properly does allow for several years worth of operation. Either way, it's a crap job. Long gone are the days of manufacturers making sleeve bearing fans easy to take apart - at least when it comes to these smaller GPU fans.

[Nergal81]

Re: Trying to repair a HP Z800 850W PSU by Delta

Hello...
I need to know the registration of the ic901.
Thanks