How to test for bad caps?

[larrymoencurly]

Originally Posted by Nagoshi

Where could I find the data sheets of the original caps? I thought we could find most of the data on the caps themselves

I was thinking about kind of upgrading the caps but this is ending up more complicated than I thought

I would have to check but I believe half the caps on the boards are those black Nichicons and they are all the same sizes. Should I upgrade them to HZ caps, or something like KZG caps? The other half of the caps are brown colored with no brand marking on them, and there are about 5 different size of caps.

CapacitorWeb has links to many manufacturer websites (click on any of the "select" buttons on the left) and also photos of the caps, including of the tops. The tops are stamped so they'll rupture if the pressure builds up too much, and the pattern of the stamp can help identify the brand, at least if it's not the usual X or Mercedes logo. For example, an "M" logo on the plastic and a "T" stamp on top indicates Matsu****a, AKA Panasonic.

I'm no expert, but I wouldn't bother upgrading Nichicon HMs to HZs unless the price was the same. And because of what the experts at BadCaps.net have said, I've been avoiding Chemicon KZGs and have been replacing the ones already in my mobos.

On one mobo, I expected to change just the caps for the voltage regulators (CPU, AGP, and memory) but ended up changing several 100uF caps as well because they were infamous G-Luxons.

[Nagoshi]

From what I can gather, the brown caps are all KZG, KMG and KMA. With what caps should I recap them? They all have a brown shroud.

All the Nichicon are HMs, Ill have to check but I believe they are all 1000uF 6.3v, as they are all the same shape and size.

Ill ask in a DFI forum and maybe send some e-mails to some mobo re-cappers about what should I use, but if you could put some light on what should I use to recap the whole board, I would be really happy

Could I replace the Chemi-con caps with similar specs Nichicon caps?

[digitaldd]

You know with the extra expense of the higher end mobos now it does make sense to replace bad caps on newer high-end motherboards. But on a socket 754 or 939 mobo I'd just use it as a chance to upgrade. I'm doing just that right now as I have an ASUS A8V that has just started acting a little flakey after one cap became a little darker colored.

Just my 2 cents.

[Nagoshi]

Originally Posted by digitaldd

You know with the extra expense of the higher end mobos now it does make sense to replace bad caps on newer high-end motherboards. But on a socket 754 or 939 mobo I'd just use it as a chance to upgrade. I'm doing just that right now as I have an ASUS A8V that has just started acting a little flakey after one cap became a little darker colored.

Just my 2 cents.

Well I dont see how I can upgrade with $0, so Ill have to make do with what I have.

The AM2 is going away, all I have left are dead P4 478 boards and an ASRock K8Upgrade-VM800 which is another 754 board, but on a lesser chipset with a very basic OC ability (auto/normal/high voltage settings on the CPU and RAM is nothing to be proud of).

So might as well live on the ASRock board till the DFI is fixed, then get back on the DFI. Its still snappy for what I do, and the tiny bit of gaming I want to do can be handled by the 6800GT for now, so Ill just collect some money and buy stuff when I can.

Id love to upgrade, but my wallet is crying, and I just cannot afford anything else.

[larrymoencurly]

Originally Posted by Nagoshi

From what I can gather, the brown caps are all KZG, KMG and KMA. With what caps should I recap them? They all have a brown shroud.

All the Nichicon are HMs, Ill have to check but I believe they are all 1000uF 6.3v, as they are all the same shape and size.

Ill ask in a DFI forum and maybe send some e-mails to some mobo re-cappers about what should I use, but if you could put some light on what should I use to recap the whole board, I would be really happy

Could I replace the Chemi-con caps with similar specs Nichicon caps?

At BadCaps.net, Big Pope and Yanz have compiled this table of leading Japanese brands, showing which series are equivalent to one another: comparison of various high quality capacitors, listed in order of decreasing ESR. IOW you can replace models high in the table with any lower down.

KZG, KZJ, KMG, and KMA are caps from Nippon Chemicon (NCC) and United Chemicon (UCC), which make high quality products. So I'd leave the KMG and KMA caps alone, but apparently KZG and KZJ models have been rare lemons for Chemicon and should be replaced even when they're not bulging or leaking. KZG can be replaced with Nichicon HN or HZ series

Nichicon HM caps are fine, unless their date codes are about 2005 or earlier (05xx, where xx = week of the year), so if they're newer and aren't bulging or leaking, leave them alone, too. But they can be replaced with Rubycon MBZ or MCZ, Panasonic FM or FC, or Sanyo WG.

Generally if you find one bad cap on a mobo, replace all the other identical caps same brand, model, and size), even if they look good, because they've probably all been working under the same load and heat. If your DFI K8Upgrade-VM800 mobo is like this one:

http://prohardver.hu/dl/cnt/2004-11/484/dfi/mobo.jpg

The caps that work the hardest are the 11 in the upper right, next to the donut coils (CPU voltage regulator), the 4 big ones next to power transistors Q14 and Q15, between the VIA VT6307 chip and the SATA sockets in the middle (video slot voltage regulator), the caps around the memory slots, including the ones next to U23 (memory voltage regulator), and the caps to the right of them, between the memory slots and heatsinked north bridge chip

[Nagoshi]

This is the DFI LP UT nF3 250GB, the K8Upgrade-VM800 is an ASRock board and works fine

The first cap that I have seen leak is right over the two "lower" SATA ports, and in that pictures, they are all Chemicon caps, while some of mines (more like half) are Nichicon. They are also all dated 2003 if I remember.

Can't I replace the HM caps with HZ? If I could replace all of them with the same caps, just different sizes, that'd make the whole thing easier.

I believe I also have a couple of Chemicon that are going bad, I think one/some of them are KMG and KMA, so I should replace them with the same thing?

thanks alot for your help btw

[davidhammock200]

As long as the uF rating is the same & the voltage & temp ratings are equal or higher (within reason) they will be fine.

[larrymoencurly]

Originally Posted by Nagoshi

The first cap that I have seen leak is right over the two "lower" SATA ports, and in that pictures, they are all Chemicon caps, while some of mines (more like half) are Nichicon. They are also all dated 2003 if I remember.

Can't I replace the HM caps with HZ? If I could replace all of them with the same caps, just different sizes, that'd make the whole thing easier.

I believe I also have a couple of Chemicon that are going bad, I think one/some of them are KMG and KMA, so I should replace them with the same thing?

HMs can always be replaced with HZs, and HZs are so good that it seems everything except maybe poly caps can be replaced with them. But if you can't find HZs in the right size or want something cheaper, there's no reason to avoid HMs and HNs any more. Chemicon KMG and KMA don't seem to have particularly low ESR, and the comparison table by Big Pope and Yanz at BadCaps.net indicates they're just general purpose 105 Celcius caps, meaning almost any Samxon or Japanese brand and model cap will be a safe substitute.

[§k¥¥ |{£øúÐz]

besides checking for physical deformations, you can test capacitance with a high end multimeter (fluke ftw, others work but aren't nearly as precise)

i've intentionally blown electrolytic caps, it's fun lol. charge up my capacitor bank, then discharge into a small 0.01 uf cap. the 50 f bank wins every time! lol

replacing them... that's the hard part. you have a desoldering pump/tool?

Additional Comment:

digikey.com = newegg of semiconductors btw, forgot to mention

[Nagoshi]

I have a soldering iron but it's probably too hot (50w), but I know somebody who could let me use a lower wattage one Im sure of that.

[davidhammock200]

Originally Posted by Nagoshi

I have a soldering iron but it's probably too hot (50w), but I know somebody who could let me use a lower wattage one Im sure of that.

A vacuum de-soldering tool is pretty much required.

[Hickeydog]

It takes a little skill, but you can de-solder through-hole stuff with just an iron.

[davidhammock200]

Originally Posted by Hickeydog

It takes a little skill, but you can de-solder through-hole stuff with just an iron.

Those caps are in a high-density area, so IMO, investing a few dollars in a good "solder sucker" is only common sense.

[Oklahoma Wolf]

Originally Posted by Nagoshi

I have a soldering iron but it's probably too hot (50w)

50W will barely do it on a multilayer motherboard. I use a 60W. Vacuum desoldering tools are almost useless on these - I usually use either a stainless steel sewing needle to clear the holes or a dental pick. You have to heat up the joint and push the needle through, all while taking care not to damage nearby traces.

This is not a newbie friendly job... if you've never done it before, best to find an old mainboard to practice on first.

[Nagoshi]

thanks for the pointers OW, and thanks for chiming in

I think I know somebody who has the same board as me, but is zapped. All the caps are in perfect shape. I could possibly get the board for free, would it be worth using the zapped board as a part board for the caps?

Also, his board (inc. a couple of ones I saw on the net) has ALL Chemicon caps. I have 20/58 caps made by Nichicon. Would that change anything if I decide to salvage the zapped board?

Wondering if I should transfer caps from a dead board to mine, or just go and buy new parts?

As for the practice, that's no problem, I have like 3-4 dead P4 boards around... surely I could practice on them.

How do you use a sewing needle on an iron? (Probably a noob question )

[Oklahoma Wolf]

Don't re-use parts from a dead board - you don't know how good of shape that stuff is in. You might have a year or a week of life in those caps and you'd never be able to tell. If anything, use it for solder practice.

Lots of good info at badcaps.net on soldering methods - I'd try to explain better but my ankle feels like someone took an axe to it (sprained) and I need to go get some rest.

[davidhammock200]

Originally Posted by Oklahoma Wolf

Don't re-use parts from a dead board - you don't know how good of shape that stuff is in. You might have a year or a week of life in those caps and you'd never be able to tell. If anything, use it for solder practice.

Lots of good info at badcaps.net on soldering methods - I'd try to explain better but my ankle feels like someone took an axe to it (sprained) and I need to go get some rest.

You type with your toes? That explains some of the things I have noticed in your reviews!

[larrymoencurly]

Originally Posted by Nagoshi

I have a soldering iron but it's probably too hot (50w), but I know somebody who could let me use a lower wattage one Im sure of that.

Here's Willawake's excellent guide to replacing mobo caps:

http://www.badcaps.net/forum/showthread.php?t=485

Practice on a junked circuit board made of at least four layers of copper because anything with fewer layers isn't nearly as difficult to desolder.

50W is not excessive for desoldering a multilayer circuit board and actually may not be quite enough power for lead-free solder. But an iron that's somewhat too powerful is safer than an underpowered one because the latter takes longer to completely melt the solder.

You can usually remove caps by heating and pulling on one lead at a time, alternating between them until the cap is completely out. Then you'll probably have to clean out the holes in the board with either a solder sucker (bulb or plunger type), a dental pick (as Willawake describes), or copper desoldering braid.

One key to successful desoldering is adding fresh 60-63% tin, 37-40% lead solder to stubborn joints. Fresh solder can help so much that some people add solder before even attempting to desolder anything.

Originally Posted by Nagoshi

I think I know somebody who has the same board as me, but is zapped. All the caps are in perfect shape. I could possibly get the board for free, would it be worth using the zapped board as a part board for the caps?

Also, his board (inc. a couple of ones I saw on the net) has ALL Chemicon caps. I have 20/58 caps made by Nichicon. Would that change anything if I decide to salvage the zapped board?

I've had a few caps that looked physically perfect but were so bad that they couldn't even pass the ohm meter test (ohms will first measure zero but gradually increase as the cap charges up), which is one of the least reliable tests there is for caps. Even a capacitance meter alone isn't good enough, and I've seen some bulging caps, including notoriously bad Fuhjyyus in old Antec PSUs, measure normal for capacitance. ESR seems to be a much more trustworthy indicator, provided the cap isn't shorted (the ohm meter test can check for that). Also experts warn that some caps look and measure fine but fail anyway from age, including Chemicon's KZG and KZJ series (but their KZE is OK). And if a used cap fails soon, you'll have to desolder and solder the board again, exposing its epoxy again to aging and increase the odds of copper traces, especially plated-through holes, separating from the fiberglass. When I reuse old caps I look for perfect physical appearance, capacitance within tolerance, like-new ESR (not just acceptable ESR), and the particular brand and series having a good reputation for reliability and long life. But even then I'll avoid putting in used caps for anything involving high current.