Dell Precision 470 Workstation

[PCBONEZ]

Re: Dell Precision 470 Workstation

Im guessing the polys are the blue ones?

Yes

Why are Samxons "daring", expensive?

Samxons aren't Japanese and some specific series have had problems.
[I think it was GL and [maybe] GS series'. Not too sure on that...]
Some people think they're great and others don't trust them.
- In some sizes using Samxon is the only way to get around the cheap Chinese and Taiwanese caps due to low/no availability of appropriate sized Japaneses caps. For example if you need to replace 3300uF or 4700uF 10mm caps in a PSU and it HAS to be 10mm then Samxon RS 3300uF is about the only option.
.

[bigcape]

Re: Dell Precision 470 Workstation

it already has polys on it... put some good rubycons or panasonics (or samxons if you are daring) on it...

Im guessing the polys are the blue ones?

Why are Samxons "daring", expensive?

[ratdude747]

Re: Dell Precision 470 Workstation

it already has polys on it... put some good rubycons or panasonics (or samxons if you are daring) on it...

[bigcape]

Re: Dell Precision 470 Workstation

Just reread your post again, to clarify;
The input capacitors that sits in the input of the CPU VRM should not be replaced by poly capacitors, only the ones that sits on the CPU VRM's output should be poly capacitors

Please try to take some better pictures of your actual board so we can get a better understanding of what is wrong, and it wont hurt to open up the powersupply aswell, so long you make sure it has been discharged so you don't kill yourself by the voltages present inside!

Here is my actual board.


Thank you for all your help!

[bigcape]

Re: Dell Precision 470 Workstation

bigcape; If you want you can buy the mainboard from me that I recapped in the beginning of this thread, because I don't use it anymore
It is a version (as you can see) with no Poly caps near the CPU VRM

That version does not support the dual core Xeon processor, which I wanted to use.
So I bought a later revision of the mainboard, that comes standard with Poly caps... Works great...

If you still want to recap your with Polys I can open up my system and take a look what Poly caps it uses

But it is strange yours would kill the Rubycon capacitors, the reason mine failed was it used the known bad Nichicon HM capacitors
Rubycon should not fail, and the first capacitors to fail should be the ones near the CPU (if they are electrolytic, and not Poly capacitors)
On your board you seem to imply that the input VRM caps have failed, that would sound to me that the reason is your powersupply is faulty
Genuine Rubycon capacitors should not fail on this mainboard (It could also be that your capacitors are not genuine Rubycon capacitors, it is very hard to make out on your photo, the colors look all wrong but that could be to the way you took the photo aswell)

I see that my white ballance was wayyyy off so I retook the shot:
[/IMG]

[bigcape]

Re: Dell Precision 470 Workstation

We repair broken things.
We talk about what shows up here broken.

I get it! I LIKE it too!

Fixing broke things is fun even if costs more in the end. Just some of the equipment I've ended up buying to fix a 5 dollar analog meter ended up costig me A WHOLE WORKSHOP and a new hobby.

Hell just a few weeks ago I set up a darkroom and so far have only had the time to make ONE print! (came out purdy good too!)

Look at my signature pic.... Thats a result of ONE bad harddrive....the rest is "History" as they say, i mean a MESS!


Sean

[PCBONEZ]

Re: Dell Precision 470 Workstation

That was a picture just taken off the web, not of the actual board

What he said.

That's why the post said: "The photo is one that has been poly'ed."

[Per Hansson]

Re: Dell Precision 470 Workstation

i see the board was already poly modded... didn't know...

That was a picture just taken off the web, not of the actual board

[ratdude747]

Re: Dell Precision 470 Workstation

i see the board was already poly modded... didn't know...

[PCBONEZ]

Re: Dell Precision 470 Workstation

Thanks Per Hansson ,,, That's two votes the check the PSU.
Anyone else?
Anyone?
Anyone?

[Per Hansson]

Re: Dell Precision 470 Workstation

Just reread your post again, to clarify;
The input capacitors that sits in the input of the CPU VRM should not be replaced by poly capacitors, only the ones that sits on the CPU VRM's output should be poly capacitors

Please try to take some better pictures of your actual board so we can get a better understanding of what is wrong, and it wont hurt to open up the powersupply aswell, so long you make sure it has been discharged so you don't kill yourself by the voltages present inside!

[Per Hansson]

Re: Dell Precision 470 Workstation

bigcape; If you want you can buy the mainboard from me that I recapped in the beginning of this thread, because I don't use it anymore
It is a version (as you can see) with no Poly caps near the CPU VRM

That version does not support the dual core Xeon processor, which I wanted to use.
So I bought a later revision of the mainboard, that comes standard with Poly caps... Works great...

If you still want to recap your with Polys I can open up my system and take a look what Poly caps it uses

But it is strange yours would kill the Rubycon capacitors, the reason mine failed was it used the known bad Nichicon HM capacitors
Rubycon should not fail, and the first capacitors to fail should be the ones near the CPU (if they are electrolytic, and not Poly capacitors)
On your board you seem to imply that the input VRM caps have failed, that would sound to me that the reason is your powersupply is faulty
Genuine Rubycon capacitors should not fail on this mainboard (It could also be that your capacitors are not genuine Rubycon capacitors, it is very hard to make out on your photo, the colors look all wrong but that could be to the way you took the photo aswell)

[PCBONEZ]

Re: Dell Precision 470 Workstation

All of the caps you circled should be replaced with electrolytics.

[PCBONEZ]

Re: Dell Precision 470 Workstation

I hope this is not a thread jack..... but I am curious why you guys don't seem to like or talk about the 490 or 690.

I have 4 690's and 5 490's They are awesome machines. One of mine has quad core E5465 xeons 2.8Gz. the 490's have X5160 3.0Gz all dual procs and are screemers!

No offense but this is the only 470 I've had and in comparison it seems to be put together like Legos!

We repair broken things.
We talk about what shows up here broken.

[bigcape]

Re: Dell Precision 470 Workstation

I hope this is not a thread jack..... but I am curious why you guys don't seem to like or talk about the 490 or 690.

I have 4 690's and 5 490's They are awesome machines. One of mine has quad core E5465 xeons 2.8Gz. the 490's have X5160 3.0Gz all dual procs and are screemers!

No offense but this is the only 470 I've had and in comparison it seems to be put together like Legos!

[bigcape]

Re: Dell Precision 470 Workstation

I hope you made a cap map taking note of the polarities in addition to uF and volts..

Oh yes i did and they are numbered on the board and polarity is clear

Excessive heat will kill any lytic after a while.
The ones that didn't bloat are probably aged pretty well and since you have them out anyway....

The ones that popped i had marked with a red sharpieI was not thinking I should pull all of them

The photo is one that has been poly'ed.
Not sure if it's a newer revision or if its been rebuilt..

might just be my pen marks?

The Vcore caps can be down to 2.5v and 820uF is probably best..

All the ones I pulled were all 6.3v

The VRM-IN caps [caps on +12v that power the CPUs] need to be 16v caps and on a server I'd use at least 470uF..

Those are 16v 1000uF. you are suggesting change those?

The others you should probably leave as lytics at the original values because, without knowing exactly what they do or what actual voltage they are on, changing the uF or volts can much things up. [Little too late to check their voltages with a meter.].

There are four of the 6,3v that look in great shape. only thing is my range meter wont charge the board enough to get an accurate reading


I took your photo and circled the ones that I pulled.




If so many of them blew up how do you know if somethin much more fragile like a transistor/thyristor or a mofset isnt burned? They TO SMALL to see and toooo many of them!

After all, caps can be used as voltage regulators. Oh and how can you tell the VRM-in caps from the rest of them?

Sean

[PCBONEZ]

Re: Dell Precision 470 Workstation

When choosing replacement caps pay attention to old-vs-new diameters.
That will bite you when they don't fit later on.

And check your power supply too........

[PCBONEZ]

Re: Dell Precision 470 Workstation

I hope you made a cap map taking note of the polarities in addition to uF and volts.

Excessive heat will kill any lytic after a while.
The ones that didn't bloat are probably aged pretty well and since you have them out anyway...

The photo is one that has been poly'ed.
Not sure if it's a newer revision or if its been rebuilt.

The Vcore caps can be down to 2.5v and 820uF is probably best.
The VRM-IN caps [caps on +12v that power the CPUs] need to be 16v caps and on a server I'd use at least 470uF.

The others you should probably leave as lytics at the original values because, without knowing exactly what they do or what actual voltage they are on, changing the uF or volts can much things up. [Little too late to check their voltages with a meter.]

.

[bigcape]

Re: Dell Precision 470 Workstation

Hey all,

I was sent over here to get some advice on "poly caps"?

This was my Exchange 2007 server that crashed, umm.. burned up day before yesterday.



She gave no warning just quit. I have taken them out (but y'all say these are top caps so.....?) with a HAKKO 808 desoldering kit. (darn thing works fantastic!

Here I was thinking I was going to pop into RadioShack, but I now see that is not going to work as hoped

[TonyBerry]

Re: Dell Precision 470 Workstation

I decided this might be a good time to upgrade my "aging" Weller WES-51, so I purchased a Weller WESD-51. As expected, it really didn't do much better at removing these capacitors. It does seem to be getting more heat to the components though, because as I heat the backside of the board, the capacitor is getting so hot I can barely touch it to pull it out. I was able to get a good number of the capacitors on the areas without the massive ground plane, but no such luck on the "important" ones.

I'm considering something more aggressive at this point. If I could precision drill out the holes that the capacitor legs go through, I could save a lot of time and energy. I have also considered pulling the capacitor casings off and solder the replacement capacitors to the existing legs.

I've also thought about asking the local hobbyists who think they have some extreme soldering skills to do it for me. I'd offer them 50 cents a pop to remove a capacitor. They would jump at the chance to make "quick money", but they'd probably hate me (or refuse to do any more) after the first board.