When to Choose ZL vs. MCZ

[bgavin]

Re: When to Choose ZL vs. MCZ

Thanks for the pointer to the AKOR procedure. I added the PDF to my library.

I've given up on recapping dead boards, until I figure out how to use the above procedure to see if I have a good chance of reviving the board. Future recaps will be done only to boards that are still alive.

It appears the answer to my original question in this thread is: use ZL(x) for power supplies and power-supply related components such as the ATX-12V board input. Use MCZ for critical VRM caps, and optionally for board field caps.

[PeteS in CA]

Re: When to Choose ZL vs. MCZ

Newark carries some ZL.

[starfury1]

Re: When to Choose ZL vs. MCZ

no worries, and yeah that about sums it up
So yeah if your going to do psu repair keep stock of ZL's or Pana FC's whatever good quality cap you get at a good price.

There is a scattering of "Dead MB" posts in the forums but unfortunately scattered be the operative word.

Maybe we need an "Dead MB" sticky and as people come across posts they can then just drop a link (if they would be so kind) to it in that thread with make model and possibly short description. of fault.
Might save a bit of searching

Anyway leave that to TC and the mods to think about

The bit on "PWR good Signal" is relevant as its the "trigger" for the startup procedure of the MB.
how often a failure on an MB of this is likely to occur I don't know.

you may want to hope there is a common failure mode as at lest a "cause and cure" will be known but it could be write off time for the MB anyway...at lest that may save you a lot of time in trouble if its is as you could identify it quickly...
(some MB just Have weak links in the chain so as to speak)

if I find anything I'll let you know

Cheers

Footnote: I actually thought the ZL series was phased out but from posts around here seems not...I could be wrong...maybe it was while they were changing to RoHs lines

[PCBONEZ]

Re: When to Choose ZL vs. MCZ

Close enough.

In so far as standard use (as in from the Factory)

ZL -
VRM on P3 or older.
In better PSU's.
"Field caps" on any board.
Found in ATX-12V or 12v input but some boards use better.
- - - Maybe better is not necessary but they do it.

I have a 1.4 GHz Tualatin capable Dual P3 server board that is 100% ZL from the factory.

MBZ/MCZ -
VRM on P4 or older.
Often in ATX-12V or 12v input but some boards use lesser.
Occasionally found as "Field caps" when the manufacturer chose to not use lesser caps (that would be perfectly acceptable there) for marketing purposes or possibly to use fewer caps in the field.
-
Acceptable as replacements in PSU's if you need to take advantage of the (usually) smaller physical size for a given uF/volts/ESR rating.

~~~

"Life" is misunderstood and over emphasized.

Don't confuse the "Life Time", "Load Life", "Endurance" (all the same meaning) rating as an estimated life span. - That's just not what it is.
-
There are equations to estimated the life span from the Load Life but it's accuracy is only +/-60% due to the fact that so many of the inputs to the equation are in themselves only estimates or ranges.
Multiply a number with a +/-20% deviation by another with +/-20% deviation by another with similar... You see.
When you get done with all the math you end up with a figure like "Between 3 and 7 years" which isn't particularly useful.

What Load Life actually is: (Lets say 2000 hrs)
Take a cap and operate it for 2000 hours at max volts, max ripple, max temperature, and so forth.
Then return it to normal conditions.
If the ESR, capacitance, and leakage are all in spec then it passed.
-
There is no assumption whatever as to how long it will continue the be in spec after the abuse.

Also the stated rating is somewhat arbitrary.
-
They aren't going to do 200 or 300 tests to zero an exact number.
The rating is applied to all the caps of the same diameter in the series. If these were exact numbers every single can size would have a different number and they all wouldn't be in even 1000's.

.

[PCBONEZ]

Re: When to Choose ZL vs. MCZ

Need to correct typo fro PWR_OK post.
Meant to say:

According to the ATX Power Supply design specs the PWR_OK signal must be sent in less than 500ms from the time the PSU is turned on.

If it's too slow the CPU won't start.
-

[kc8adu]

Re: When to Choose ZL vs. MCZ

no worries, and yeah that about sums it up
So yeah if your going to do psu repair keep stock of ZL's or Pana FC's whatever good quality cap you get at a good price.

There is a scattering of "Dead MB" posts in the forums but unfortunately scattered be the operative word.

Maybe we need an "Dead MB" sticky and as people come across posts they can then just drop a link (if they would be so kind) to it in that thread with make model and possibly short description. of fault.
Might save a bit of searching

Anyway leave that to TC and the mods to think about

if someone wants to start such a thing go for it.
i will sticky it.sounds like a great idea.

[spiff59]

Re: When to Choose ZL vs. MCZ

Dell's free ride on replacing GX270 motherboards ends this month, so, planning for the future, I'm starting to shop caps or cap kits for manual replacement.

I had already crossed Rubycon MCZ's off my list, yet find they are touted as reliable here. The following photo is a late-model (Rev A02) GX270 mobo with 15 caps that have barfed all over (the 2 that look decent puked the electrolyte out the bottom). The entire batch (as shown by inset in lower-right corner) are Rubycon MCZ's. So... what gives? MCZ's are good? or garbage? Or do you have to go by date codes to find ones with a 'corrected' formula?

[PedroDaGr8]

Re: When to Choose ZL vs. MCZ

I have heard the PSU for this device can do that.

[starfury1]

Re: When to Choose ZL vs. MCZ

if someone wants to start such a thing go for it.
i will sticky it.sounds like a great idea.

Thank you KC8

I started one in the FAQ section
If you think it needs to be edited moved etc then please do so.

it seems like an FAQ type situation question as in;

"I've changed the caps it still wont boot and I am sure there's nothing wrong with my recap and PSU, whats my next step? type question...should add thought its probably a very good idea to check the VRM and voltage supply before inserting CPU! & memory anyway.

Cheers

[starfury1]

Re: When to Choose ZL vs. MCZ

MCZ are suppose to be a quality cap but like any cap are subject to heat and being stressed beyond their limits.
(rubycons don't fail that often is my understanding)

I don't know the situation with those MB personally so cant answer why that type of failure has happened at such a level
(except for the possible domino effect)

its possible a crap stressed PSU may well have helped in their demise too.

I don't recall there being any bad batches of the MCZ line but don't know for sure
they are the replacement for MBZ series so think the manufacture is after the bad caps formula period.

I could be wrong as I said.

Another possibility is OCing which is going to cause extra stress and heat on the VRM and caps.(and a hotter CPU)
So maybe very hot CPU heatsink next to them or just plain bad ventilation

Bottom line is they are reliable quality cap when run within specs from what I gather here, so I am a little surprised to see them in that state.

What was the situation the MB was being run in? out of curiosity

guess there's a few here who know these boxes and give a better comment on the situation as to why they died, but that failure is almost worthy of GSC

last possibility, and really more a question for those out there...
is it possible they are counterfeits?...seems to be a bit of that going on in the cap world.

Welcome and Cheers

[kc8adu]

Re: When to Choose ZL vs. MCZ

all of the very few mcz failures have been in dell gx 270 units.
the psu is suspect as i have been seeing lots of them come down with badcaps.
anyway the whole mess runs way too hot .next one that crosses my bench is getting polymers.

[spiff59]

Re: When to Choose ZL vs. MCZ

We have 13 (lucky, huh?) of the GX270 SFF's here. They all run 24/7. They are placed in fairly well ventilated areas but use only the (inadequate) stock cooling. Both DIMM slots are populated (512 * 2), but AGP and PCI slots are unused. The processors vary from 2.66 to 3.2mhz with a mix of Northwood and Prescott cores. The processors are likely taxed somewhat most of the time as, having no true video card, they do all the work in displaying Serenescreen's Marine Aquarium 2 (hi-res) screensaver most of the day (the patients love it). The actual applications in use are for X-Ray image display and simple document edits.

The machine that had the mass MCZ failure was a 2.8mhz Northwood, one of the models with a copper/heatpipe heatsink. Some of our boards are labelled "Foxconn" but this was one of those marked "Vesuvius" (cracks me up, this board had 15 little 'volcanos' erupting). For grins, I pulled the PSU, a Dell PS-5161-7D, and replaced it with a spare Dell PS-5161-1D1S I had on hand. I am not sure of the difference but they appear identical as far as connectors, wattage, physically, etc. I pre-inspected the new PSU and it looked fine, then I popped open the PSU that was running the show when all the MCZ's said "Uncle!" Other than a couple dust bunnies, there were no swollen/leaking caps, nor any sign of thermal discoloration anywhere. I could measure voltages, possibly while under load, but don't have the means to monitor for spikes, transients, etc.

I'm still unsure if it may be a faulty power supply, or, if I shouldn't trust MCZ's (at least under higher temp conditions).

So, the low-esr solid polymers are rated for temps above 105 degrees?
Heck, I'd sleeve axial caps and put them in here if that was what was going to be most reliable in this medical environment. I care little about aesthetics.

Does TopCat offer (or recommend) any polymer options in his kits? Would adjustments to the original uf/mfd values be necessary? Any good sources for compatible polymers?

Thanks.

[starfury1]

Re: When to Choose ZL vs. MCZ

err correct me if I am wrong but don't the Northwood get a little hotter.

Well dont know what the issue might be with the PSU but solid polymers don't have a liquid electrolyte so don't dry out...I think you can use lower values UF wise too
(due to ESR)

I do remember something about them that is or maybe an issue ..what I cant recall.

Anyway KC says they are hot boxes so maybe thats at lest part of your answer
using polymers

Correct this if I barking up the wrong tree here somebody

Dont know if TC does do them I think not but pm him or check the site

cheers

[gonzo0815]

Re: When to Choose ZL vs. MCZ

I would just use polymer capacitors in this case, they have superior endurance at high temperature, lower ESR and lower Z and a very high ripple current rating.
Half the capacitance should be sufficient in case of polymer cap replacement. But a pretest should not hurt.
If the capacitors in the PSU are from unknown brand, just replace them too with some reputable brand (no need for polymers there) and same capacitance.

[kc8adu]

Re: When to Choose ZL vs. MCZ

i laughed when i saw the first vesuvius board with all the erupting nichicon hn/hm
some had volcanoes or anthills on top.
i am waiting to get my hands on a 270 to do a polymer mod.my big clients with thousands of these want to wait till they get an extra to try.
i want to stuff one with polymers and beat it up to test.
if tc does not offer them drop me a pm as i have a ton of them on hand.
or if he needs some to do a board for you i can provide him with some.
if anyone wants to donate one of these boxes for a test i will set it folding for badcaps team.

[PCBONEZ]

Re: When to Choose ZL vs. MCZ

I can't see well enough to tell in the pic.
Is the polarity is correct on all the original caps?

Even one Ruby blowing is pretty rare but a whole board full?
Makes me think something else wrong caused then to eat it.
Bad PSU. Bad solder job shorting something, maybe even a bad/shorted CPU.

.

[Big Pope]

Re: When to Choose ZL vs. MCZ

i laughed when i saw the first vesuvius board with all the erupting nichicon hn/hm
some had volcanoes or anthills on top.
i am waiting to get my hands on a 270 to do a polymer mod.my big clients with thousands of these want to wait till they get an extra to try.
i want to stuff one with polymers and beat it up to test.
if tc does not offer them drop me a pm as i have a ton of them on hand.
or if he needs some to do a board for you i can provide him with some.
if anyone wants to donate one of these boxes for a test i will set it folding for badcaps team.

Great!! It seems very interest for this matter. I am willing to donate Samxon GC series and X-CON ULR series(Samxon's polymers) for this event.

[PCBONEZ]

Re: When to Choose ZL vs. MCZ

The Load Life / Endurance rating seen in data tables is not the Lifespan estimate.

[spiff59]

Re: When to Choose ZL vs. MCZ

Yes, the stripes are all lined up like good little soldiers, no polarity issues here. The PC actually ran anywhere from 1 to 15 minutes before freezing with the board with the 15 leaking MCZ's. The PSU ran fine for a day with the new motherboard before I swapped it to give it a visual inspection, which it passes. The CPU is up and running for 2-3 days now without a glitch. The air exhausting out the back is MUCH cooler now, having functioning capacitors.

I was leaning towards it being a thermal issue causing the MCZ's to fail. Is it feasable that these 15 electrolytics would boil due to overheating, and not one other single component in the system fail?

By the way, the replacement mobo is another with the "Vesuvius" sticker (not the "Foxconn" sticker"), but the metal support bracket underneath the board, that attaches the plastic heatsink holder has an interesting stamp embossed into it "Foxconn 12/JUN/07". Looks like Foxconn has the contract to refurb GX270 boards regardless if they were the original manufacturer or not? The Refurb sticker on the motherboard box identfies it as a "VESUVIUS KILLERBEE" (There's a job I want, naming motherboards!). The refurbed board has a mix of Rubycon MCZ's and Panasonic FL's.

I inventoried all 13 machines here, I have some work to do...
Five more have leaking caps (I didn't get in there close enough to check brands yet). On all 5 machines the cap at the end of the AGP slot is leaking. Three of the five machines also show some leakage on caps near the CPU and voltage regulators. I think one or two of these are going to "fail" before Jan 31st <lol>. The rest I'll have to recap myself (although it's a bear with my little 40W Weller station. I might try a trick someone in here mentioned, that of warming up the affected area of the board first with my heat gun. I'm a bit corcerned about overdoing it and having SM components shifting around. I'm not too bad with a soldering gun, but mix in tweasers and a magnifying glass and I'm in trouble).

Is there a downside to using polymers of the same capacitance? Price? Physical size? Availability?

PS - Maybe my last "free-swap" board to return to Dell after the 31st deadline will mysteriously get shipped to the worng address and end up in one of your hands for experimentation...

[kc8adu]

Re: When to Choose ZL vs. MCZ

Great!! It seems very interest for this matter. I am willing to donate Samxon GC series and X-CON ULR series(Samxon's polymers) for this event.

cool!
i may have 2 of these little desktop blast furnaces coming in as donations.
i will do one up in your parts and the other in one of the polymers i have.