Intel D845EBG2 recap opinions

[yyonline]

I have 2 computers in the shop. Both have Intel D845EBG2 motherboards, both have failed capacitors in the same place.

Board A:
VRM is a mix of UCC KZG and Nichicon NA polymers.
2 big Nichicon HD capactors
Nichicon VR (85*C) elsewhere (1000uf and smaller)

Board B:
VRM is Nichicon HM with 2002 datecode and Nichicon NA polymers.
2 big UCC KZE capacitors
Nichicon PW elsewhere (1000uf and smaller)

Both boards have bulging caps in the VRM area, near the CPU heatsink.
Board A has 2 bulging KZG out of 4 total in the VRM area.
Board B has 1 leaking and 3 bulging HM in the same area, but these are from the bad date range.

Both computers had older FSP power supplies with all sorts of leaking Fuhjyuu caps.

Interestingly, both boards could run Memtest86 and Prime95 for 48 hours each with no stability issues.

I figure the bad electrolyte caused the NM to fail, and a combination of heat and dirty power caused the KZG failure.

My plan: Replace power supplies with Delta units with good capacitors (done). Replace all HM and KZG caps with Rubycon MBZ.

Should this be sufficient? Is there any need to replace the Nichicon NA polymers on the VRM? Are the two large caps connected to the VRM (HD on Board A, KZE on board B) - Are these VRM input caps? (I'm new to component repair - bear with me...) Any need to replace those? The polymers and the large caps show no visible signs of failure, but I didn't know if dirty power from a failing PSU could have damaged them.

Board A image attached. Board B looks the same, but with different brands as mentioned.

[linuxguru]

Re: Intel D845EBG2 recap opinions

Yup, MBZ will be fine at the VRM output. VRM input caps are subject to much lower stresses and fail relatively rarely.

[PCBONEZ]

Re: Intel D845EBG2 recap opinions

KZG, HM, and VR need to go.
.

[yyonline]

Re: Intel D845EBG2 recap opinions

Thanks for the tips, guys! I have some MBZ left over from my last project, but I'll have to order some more before I can start to actually tear down the boards. I'll post back with the results once everything is back together.

[hardwareguy]

Re: Intel D845EBG2 recap opinions

VR has NO place on a mainboard! Its only good for 85C and its not even Low ESR! Its a general purpose cap.

What was Intel thinking here?

[yyonline]

Re: Intel D845EBG2 recap opinions

Actually, taking a second look, all the VR caps are 220uf or less. Also, all are 25V, which seems a bit unusual to me. Most boards I've looked at have 6.3V for most of the scattered motherboard caps. Perhaps the higher voltage rating compensates a bit for the otherwise not so good caps? Either way, despite my recommendation (based on forum advice), the the owner opted not to replace the VR caps. Her reasoning was that if it was stable for 6 years with less than ideal VR capacitors, they're good enough, and it's a light use computer used about 4 hours a week. I told her no guarantee unless I replace all of them. Oh well, not the way I recommended to fix it, but I can only do what the customer will pay me for. I'll be keeping an extra close eye on those VRs in future checkups.

It will be interesting to compare specs on the smaller caps once I get the second board back in the shop for a recap, as that board had PW in place of VR caps, and I could have sworn there were a few 1000uf PWs on the other one.

[PCBONEZ]

Re: Intel D845EBG2 recap opinions

You need to explain to the,, ah,, thee,, ah,,, the 'customer' that capacitors wear out.

Quite easy to get the idea across to a clueless wonder.
Caps have electrolyte and plates just like a car battery.
The chemicals in them work pretty much like a car battery.
They dry out and wear out,,, just like a car battery.

Intels Marketing Guru's determined that the useful lifespan of a motherboard is 7 years.
They then build the hardware to last 'at least' 7 years.
VR should last 'at least' 7 years if they are properly cooled and never stressed.
- But they won't last much longer than that and if the system is hot they won't make it that far.

A D845EBG2 would be ~ 6 or 7+ years old about now.
TPS was printed Apr 2002.

I had an early Intel P4 board in recently where every 100uF 25v VR cap on it was bad.
I think about 1/2 were bloated but you had to look close to tell.
[Pretty sure I uploaded pics someplace here.]
.

[yyonline]

Re: Intel D845EBG2 recap opinions

Well I am happy to report both boards have had the bulging/leaking VRM caps replaced. Both are running stable now.

PCBONEZ, that's very enlightening info on intel's 7 year useful lifespan. I shared that info with the owner. She still insisted on not spending the extra few dollars for more capacitors as she plans on replacing these 2 systems in the next year. However, I do appreciate your helpful advice. If they were my systems, I'd be doing things differently.

[Krankshaft]

Re: Intel D845EBG2 recap opinions

I wish my AGM batteries in my UPSs had as long of a life as my caps .