Dell GX 620 Motherboard Recap

[ComputerGeek]

Hello Guy's I have a Dell GX 620 Motherboard that has two bloated Rubycon's on it. I should mention that the system runs fine and I had it up for 24 hours without a problem.

I have a couple questions. First, are these fake Rubycon's. The five next to the motherboard are especially suspicious one of them has a black gold label and the others have black gray even though they are the same series.

Second what Caps do you recomend replacing? I will be reselling and I need a Hard drive and a OS so I don't want to spend a ton on a Recap. Also, it is running fine so. I was thinking about replacing the (4) MCZ 6.3v 2200Uf, the (5) MCZ 6.3v 1800Uf and the (1) MCZ 16v 1000uf. Should I just worry about the (4) MCZ 6.3v 2200Uf.

Thanks!

[mockingbird]

No, these are not fakes... The first time I saw a vented Rubycon was a few weeks ago when I picked up a tower GX520 or 620 and one of the Rubycons had the "K" split... It wasn't bloated, the "K" was just split with some crusted electrolyte.

The only black/gold one I see is the 8mm one... That's fine.

In this case I would personally do a total re-cap (Not the polymer VRM chips, obviously)... But that's not half of your problem... You need to take a look at what caused this... The PSU! Crack that thing open and you'll see that the inferior caps passed so much ripple to the motherboard that it caused the Rubycon caps to bloat.

I would also replace the small cheap "YK" Rubycons with something more reliable, preferably a non-GP cap.

Replace the MCZ and MBZ with Nichicon HN. For the values where you cannot get HN, it is OK to replace MBZ with HM, but MCZ must be replaced with at least HN. HZ is good too. If you had an ESR meter, you could test the caps, otherwise, be safe and just replace them.

[ComputerGeek]

Well I open the PSU already and their weren't any bulging Caps, out of the very few that were in their. The Power Supply also barely had any dust in it so I think that it probably has been replaced. If so should I even recap it?

You really think that I need to do the whole thing huh, It's only a Pentium 4 so I don't think whoever I sell it to will be using it more than two years. Do you still think I need to do those large number of small caps on the board.

Thanks!

[mockingbird]

Post some pics of the PSU innards... Caps don't always bloat, sometimes the electrolyic just dries up on the inside. Good question about the small caps. If someone else can comment about the location of the small ones and their function, we can get a better answer regarding that.

[mockingbird]

Just by the way, I have a GX620 here, SFF, same as yours, PSU model N275P-00 / NPS-275BB B REV 02 / NPS-220BP. All electrolytic caps on the motherboard look ok. Combination of Rubycon 6.3 2200 10mm, 16V 1000 and 6.3 1800 8mm. Small caps in my case are UCC SMG as opposed to your Rubycon YK. SMG is a pretty good series, I'm going to leave them. Looks like they stopped using Nichicon VR/VZ for the small caps, thank G-D. Computer is unstable.

I opened up the PSU, all the caps look fine but I know better. Most of the caps are LTec "LZG series (Delta likes to use LTec Caps), a few Taicons, and a single UCC KZE. I had to desolder the heatsink with a couple of MOSFETs attached to get to some caps underneath, and I also desoldered the PWM/Fan Controller daughterboard which is 19 pins.

I can't test the caps, but I'm willing to bet that the replacements I ordered from Digikey will solve the problem.

If you want to know what I used, let me know I can post the list.

[Topcat]

I do have a kit for this board.... Only the MCZ series on it will ever give you any problems.

http://www.badcaps.net/store/product...roducts_id=105

[mockingbird]

Should I suspect the MCZ if they look ok? I guess I should really test the system with a good PSU to find out.

[kleung]

Well, I haven't tested the caps on my sff gx620 but there are 2 other problems that contribute to the failure of those caps.

1) the hard drive sits on top of them and there is no fan associated.

2) the ONE system fan sucks in air from the front; passes it over a super-hot pentium 4 processor and then pushes that air towards these caps.

the successor model (gx745) has 1) the front fan running a bit faster and 2) an optional fan under the hard drive/over these caps.

Still fail often of course since design is so tight on these sytems.

[mockingbird]

I saw that video on Youtube... He's wrong. It has more to do with the PSU than it has to do with the thermal design. Sure, it isn't helping, but I've seen far hotter chassis designs where the caps endured it.

[ComputerGeek]

Originally Posted by mockingbird

Post some pics of the PSU innards... Caps don't always bloat, sometimes the electrolyic just dries up on the inside. Good question about the small caps. If someone else can comment about the location of the small ones and their function, we can get a better answer regarding that.

Here are some Pictures, sorry they aren't that great, there isn't that much Room to take photos.

They Psu was really clean like literally had no dust in it so I think someone has replaced it. The system also ran fine in its current condition.

[OniJon]

All I say is recapping a already bad PSU doesn't make it better. Sure it lasts longer but ripple goes nuts in 90% of the cases. The caps are in parallel with the design, so they work good the time they actually work. After that you can recap, live with the ripple or toss the thing out the window. In this case, you're selling it so leave it be.

[mockingbird]

All I say is recapping a already bad PSU doesn't make it better. Sure it lasts longer but ripple goes nuts in 90% of the cases.

This has no factual basis.

Here are some Pictures, sorry they aren't that great, there isn't that much Room to take photos.

I'm pretty sure I had the same PSU. I don't have it anymore, but I still have a complete mapout and list of parts, which I make for all PSUs I re-cap anyway. I even have the list of caps from Digikey if you're interested. Let me know.

By the way, you will need to desolder that daughterboard and the heatsink with the two FETs to get to some small caps. Also, check if the Delta model is the same as the ones as I posted above.

[ComputerGeek]

Originally Posted by mockingbird

This has no factual basis.

I'm pretty sure I had the same PSU. I don't have it anymore, but I still have a complete mapout and list of parts, which I make for all PSUs I re-cap anyway. I even have the list of caps from Digikey if you're interested. Let me know.

By the way, you will need to desolder that daughterboard and the heatsink with the two FETs to get to some small caps. Also, check if the Delta model is the same as the ones as I posted above.

Sure send me the list on the PSU and the motherboard if you have it too. Thanks!

So what about the ~20 small Caps on the motherboard. The Badcaps kit doesn't have them should I really worry about them?

Thanks!

[mockingbird]

Ok give me a little time, I'm a little busy re-constructing the Tabernacle for the upcoming holiday...

I don't have the motherboard anymore, but for the small 16V 220uF Rubycon YK caps, if you really want to replace them, you can go for something like this:

http://www.digikey.com/product-detai...154-ND/3134112

That's probably the highest rated cap that exists in 16V 220uF 6.3x11mm. It's not implicitly listed in the datasheet, but based on the size, the ripple for it is 700 compared to 280 for the YK...

Also, YK is not as shabby as I thought... So you should probably leave them alone...

[ComputerGeek]

Originally Posted by mockingbird

Ok give me a little time, I'm a little busy re-constructing the Tabernacle for the upcoming holiday...

I don't have the motherboard anymore, but for the small 16V 220uF Rubycon YK caps, if you really want to replace them, you can go for something like this:

http://www.digikey.com/product-detai...154-ND/3134112

That's probably the highest rated cap that exists in 16V 220uF 6.3x11mm. It's not implicitly listed in the datasheet, but based on the size, the ripple for it is 700 compared to 280 for the YK...

Also, YK is not as shabby as I thought... So you should probably leave them alone...

Ok no problem I am not in any terrible rush to get it done.

I think I'll leave the small YK Caps. Thanks!

[ComputerGeek]

Mockingbird did you ever get that list together?

[mockingbird]

Ah sorry, I have it here, let me look through it...

----
1) 1189-1076-ND
2) 1189-1074-ND
3) 565-1662-ND
4) 565-1660-ND
5) 1189-1148-ND
6) 565-1650-ND
7) 565-1674-ND
8) 1189-1076-ND
9) 565-1646-ND
10) P12927-ND
11) 493-3280-ND
12) 565-1598-ND
13) 565-1544-ND
14) P14508-ND
15) 493-3279-ND
16) 565-1545-ND
17) 493-1810-ND

This is for every single cap in the PSU, except the primary cap, which you should not change. All in stock right now. Take note, this is for the PSU only, not for the motherboard. I don't have this system anymore, so I don't know which caps need to be changed on the motherboard, but I do have a mapout of the PSU in case you can't figure out which cap replaces what, though it should be relatively obvious.