Re: HP dc7800 bad caps
Thanks for that information! I'll test the resistance...
There is only one single 1500 uF capacitor there on the board. What do you think it is used for? The system gets lots of disk I/O errors when it fails.
Jakob
jakah
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Last Activity: 08-05-2016, 04:15 AM
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Re: HP dc7800 bad caps
My lab assistant have recapped about 10 machines now, and they all run stable after recap
Now I have a question for you. Next to the failing 1500 uF OST capacitor (EC13), there is a "slot" for another capacitor (EC14). Can I put another cap in there? Is there any way of telling if that cap will end up in parallell with the EC13 cap? See attached picture. If I get no resistance with a multimeter between e.g the "+" holes of EC14 and EC13, they must be???...Last edited by jakah; 12-01-2011, 01:04 PM.Leave a comment:
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Re: HP dc7800 bad caps
Thanks for the tip about picking a cap with higher voltage! The cap that actually has gone visibly bad is the 1500 uF cap, so if I would pick polymer caps for the 470 uF caps I guess I should pick a polymer replacement for the 1500 uF aswell. I noticed that only replacing the 1500 uF cap makes the system stable. The system runs very cool anyway, so I think good regular electrolyte caps will give it a long lifetime.
What I just noticed though is that where some of my machines have 680 uF Rubies, some machines have 680 uF 10V OST RLX caps instead...Leave a comment:
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Re: HP dc7800 bad caps
Thanks for that information! Now I know better what to look for.
For the 470 uF 16V caps, the only good option I found on Farnell was a Panasonic polymer cap:
[url]http://se.farnell.com/nichicon/plg1c471mdo1/capacitor-470uf-16v/dp/1580601[/url]
Operating lifetime is a bit low (2000h). Why is that?Re: HP dc7800 bad caps<br /> <br />.../1580601[/url]Last edited by jakah; 11-03-2011, 02:56 AM.Leave a comment:
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Re: HP dc7800 bad caps
Oh, sorry, here's the right link: [url]http://se.farnell.com/panasonic/eeufm0j152/capacitor-radial-1500uf-6-3v/dp/1219448[/url]
Farnell has FC, FK, FMs of 1500 uF. The FMs seem to have the lowest ESR, or am I reading those specs wrong? They also have Rubycons. What series should I pick there?
Thanks for all help!Re: HP dc7800 bad caps<br /> <br />...f 1500 uF. TheLeave a comment:
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Re: HP dc7800 bad caps
Today, I checked my 15 other dc7800 I have in my computer lab, and all of them had a working fan, luckily! Hopefully only something with that particular machine, yes I have the same experience as you dumpystig. This model is the first one from HP I've seen problems with for a long time. I remember bad caps in some old S478 HP systems.
So now I'm about to order some caps for all those 15 machines. Unfortunately, they don't let me (easily) order stuff from companies outside Sweden, so I've been looking at Farnell. Unfortunately, they don't have...Last edited by jakah; 11-01-2011, 04:30 PM.Leave a comment:
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Re: HP dc7800 bad caps
I recapped the board, and the system seems stable so far!
However, I just noticed that the fan of the PSU has given up. The machine is just a bit older than three years. Planned obsolescence...Leave a comment:
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Re: HP dc7800 bad caps
Thanks for the advice! I ordered both Nichicons and some polies, so I can test both
Leave a comment:
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Re: HP dc7800 bad caps
So now it's time to order some caps from Topcat! My idea is to do the following replacements to see if that solves the issues (and if not, then replace all those Lelon caps aswell):
- replace the three KZG 470 uF 16V with three [B]Nichicon HN 470 uF 16V[/B]
- replace the OST 1500 uF 6,3V with a [B]Rubycon ZL 1500uF 6.3V[/B]
Will those caps be good replacements, or do you have other suggestions?Re: HP dc7800 bad caps
So now it's time to order some caps from Topcat! My idea is to do the following replacements toLeave a comment:
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Re: HP dc7800 bad caps
Thanks all for your replies! I took a picture of the polymer caps around the cpu.
Also, I forgot to say that the mobo is from a CMT (tower) version of the dc7800. Today, I'll have a look at my dc[B]79[/B]00s to see if they also have this problem!Re: HP dc7800 bad caps
Thanks all for your replies! I took a picture of the polymer caps around the cpu.
Also, I forgot to say that the mobo is from a CMT (tower) version of the dc7800. Today, I'll have a look at my dc[B]79[/B]00s to see if they also have this problem!Re: HP...Leave a comment:
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Re: HP dc7800 bad caps
Thanks a lot for your answer! The brown "mercedes benz" caps are KZG indeed. I attached a photo of the green caps (the best my smartphone camera could do).
Besides the KZGs and the OST, what caps would you suggest replacing?
Jakob...Leave a comment:
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HP dc7800 bad caps
I found this when I was troubleshooting a bunch of HP dc7800 machines in my computer lab that had started to behave strange; a bad OST cap close to the memory slots. The board has a mix of caps from Rubycon, Sanyo, some green ones where I can't read the brand, and one OST (and some labeled FL...is that a name of a brand or a particular series of one???).
I haven't recapped yet, but planning to. Anyone else seen bad caps in those machines?
Regards,
Jakob... -
Re: P4P800 Deluxe - any bad capacitor sightings?
Do the -e ones (p4p800[B]-e[/B] deluxe) use the same caps as the non-e ones?Re: P4P800 Deluxe - any bad capacitor sightings?
Do the -e ones (p4p800[B]-e[/B] deluxe) use the same caps as the non-e ones?Re: P4P800 Deluxe - any bad capacitor sightings?
Do the -e ones (p4p800[B]-e[/B] deluxe) use the same caps as the non-e ones?Leave a comment:
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Re: Why no Elna Cap for motherboard ?
I recapped my i845 mainboard with elna (RJH) caps, and still using it in my "main rig". The reason for using elna was becase that was what I could find here at that moment, back then. I admit I didn't really know what I was buying, but I figured they would work as they were low ESR.
[url]https://www.badcaps.net/forum/showthread.php?t=1824[/url]Re: Why no Elna Cap for motherboard ...for using elnaLeave a comment:
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Ga60XET recapped
I bought this board cheaply from a guy who sold it as defect. He told me it posted, but was unstable.
The board had four bad GSC caps (3300uF 6,3V), four still good Choyo caps (1200uF 6,3V) and 11 small 330 uF Gluxon caps. I replaced only the GCS and Choyo ones. I didn't mind the Gluxons as they were of such small capacitance.
As replacement I coulnd't find any fitting caps to buy, so I replaced the four GSC ones with Sanyo 3900uF 6,3V caps found in an old Dell BX board, and the four Choyo ones with a three Sanyos and one Rubycon cap (both 1500uF 6,3V) from a noisy... -
Re: Loud (coil) noise from an MSI nforce2 board. Bad caps??
Thanks for your replies guys!
Per Hansson: Your thread looks interesting, I will read it through.
-HoNY-: My board is ver:1 as yours. The only caps not mentioned in my first picture are the sixteen 1000uF caps (and a few small 470uF ones). I can't tell you the brand, but they are marked "1000uF 6,3V KZG" and their colors are green and white, as you can see in my first pic Don't your boards have the same caps as mine?
Are your boards noisy too ?
I have only...Leave a comment:
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Loud (coil) noise from an MSI nforce2 board. Bad caps??
I got an MSI K7N2G board for free a while ago. The board seems to be totally stable, though it's generating a loud electrical noise. I can't tell exactly where the noise is coming from, but I think it's somewhere near the coil next to the mosfets, or from the coil itself. The noise is really loud, I can easily hear it from another room.
What do you think is causing the noise in this case, bad caps ? No caps on the board are visibly bad, no leakage or any other sign, but as I understand they can be bad anyway.
I have tried to identify the caps on the board, but I was unable...Last edited by jakah; 07-03-2006, 12:28 PM. -
Re: Supermicro P4SBA
Thanks for you replies!
Willawake: Apparently
I used RJH ones.
Jakob...Leave a comment:
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Supermicro P4SBA
Hi!
I got an old Supermicro P4SBA board for free because it had bad caps. I bought an old cpu for it (Northwood 1,6), and new caps to replace the bad ones with. The bad ones are all labeled "NRSY 1000uF 10V". There were 14 of these. For replacement, I bought 14 "Elna 1000uF 10V"s.
I'm running x86-memtest on the system now, and it seems to be running fine!
I took a few pics of the board, before and after recapping....
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