Re: Trying to repair a HP Z800 850W PSU by Delta
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.
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...
BLinux
Member
Last Activity: 06-08-2023, 01:50 PM
Joined: 10-17-2017
Location: San Diego, CA
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Re: Trying to repair a HP Z800 850W PSU by Delta
ok, had some difficulty adding pictures earlier. they are attached here....Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
so had a little time today and opened up the PSU again. this PSU has some sort of self-test circuit, where if you connect the outlet power cable with the unit outside the computer, it will power on and a green LED will turn on steady if it passes the self-test. granted, this is done with no load. however, a few times when i've had this problem, the self test has resulted in a clicking and pulsating green LED instead of the usual steady green LED. some times it passes the self test, even when it is exhibiting the symptoms.
...Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
by that, you mean bad solder joints, right? just confirming the terminology.
if that were the case, how does one go about finding these? are there any visual queues to look for? common places in a PSU where one might find them?...Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
oh well... the PSU worked for about 3 weeks this time and then started to act up again. today, it shutdown right in the middle of applying an update :-( .. that won't end well.
so, i guess i'll open it up again and re-check the caps and post the ESR values I get.
if I don't find any bad caps, what other types of failures would exhibit this type of behavior where it works for several weeks at a time, and then spontaneously shuts off and restarts?Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
Well, strangely enough... the PSU has been stable so for the last several days. I haven't replaced any components yet. As I was digging around, I did however find a huge glob of dust sitting between 2 legs of a MOSFET. I cleaned the whole PSU out more thoroughly with a air blow gun @ 75PSI. I don't know for sure if that huge dust ball had anything to do with the problem, but i guess we'll see.
I didn't write them down, but there were in the single digit ohm range ones like the 22uF. If the problem returns,...Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
those were some of the first I was suspicious about. i was wondering the same as PeteS below about the 5VSB, and I believe those Ltecs are connected to that... but my ESR meter said they were in pretty good shape, so I don't know...
thanks for the advice... i'll be digging into that further......Leave a comment:
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Re: Trying to repair a HP Z800 850W PSU by Delta
The problem isn't that it fails often, rather, it works most of the time, and fails occasionally. So, what you're suggesting would be a way to get it to work when it is in failed mode, but what i need is a reliable way to trigger the fail at this point... it just happens randomly, which is really annoying....Leave a comment:
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Trying to repair a HP Z800 850W PSU by Delta
This is for my son's computer... got a really nice deal on a HP Z800 (12-core/48GB) for like $250 on eBay. It's been working great for a few months, but then started to randomly reset/reboot, and at times refuse to power on at all. When this happens, there's a audible "clicking" sound, like a relay switch sound. But, it's not consistent... some times the power supply works fine for weeks at a time. And then some times it runs into this resetting issue. Some times worse than others; one time it even failed it's own "BIST" (built-in self test) mechanism, which consists of pulling... -
Re: New Members - please post your introductions here
Howdy folks!
I've occasionally fixed a few electronic devices by replacing bad capacitors. I didn't know about this forum until someone pointed it out to me. I can't believe there's an entire community to discuss bad capacitors??!!! Wow!
I'm by no means an expert in electronics; more of a hobbyist. When I was a kid growing up in the far east, I briefly worked at an electronics assembly sweat shop where I learned how to solder. I didn't really get into electronics again until later in life after college....Leave a comment:
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