Opinions on whether I should use traditional electrolytics or polymers?

[jpyerry]

I am slowly getting ready to attempt my first recapping of a motherboard, it is an MSI K7T Turbo2. The only thing I'm waiting on is to buy a new soldering iron, I don't want to attempt this with my current cheapo Radio Shack iron that I hate. This board was dead when I bought it, got it for like a dollar on ebay, so if I can't revive it, I won't lose any sleep over it.

So, I am planning on using Panasonic FR caps for almost all of the capacitors (the obviously bad ones are G Luxons at 2700μF 6.3V, but I think I should replace all of them). But, the board has seven Teapo A3 1000μF 6.3V capacitors on it. I happen to have enough capacitors on hand to complete the job using either Nichicon HZ series or Nichicon L8 polymer series capacitors (both 1000μF 6.3V). So, since I have them on hand, I would like to save a little money and use them.

It seems like there is a bit of a debate on using polymer caps in place of wet electrolytics. Some say go down in voltage or capacitance, others say keep the specs the same unless installing near the VRM. I'm just really confused which would be the better choice. Should I use the Nichicon HZ's and save the L8's for another project, or for longevity's sake should I go ahead and put the L8's on the board?

Opinions, commentary, and advice would be greatly appreciated for this confused newbie. Thanks in advance.

Yours,
Justin

[ChaosLegionnaire]

Re: Opinions on whether I should use traditional electrolytics or polymers?

firstly, athlon xp cpus dont run hot unlike pentium 4s, i believe. secondly, are u going to use the system in a cramped casing with poor ventilation or in a hot area? polys are more for toaster box pcs which run very hot. polys cost a few times more than electrolytics, so if u wanna save money, u shud save the polys for "hot boxes" where they are needed most. use electrolytics for low power, cool, well ventilated pcs.

[LLLlllou]

Re: Opinions on whether I should use traditional electrolytics or polymers?

I am slowly getting ready to attempt my first recapping of a motherboard, it is an MSI K7T Turbo2. The only thing I'm waiting on is to buy a new soldering iron, I don't want to attempt this with my current cheapo Radio Shack iron that I hate.

Make sure you get something with at least 45 watts, more is better, motherboards have ALLOT of copper and multiple layers, and will wick away heat quickly. Some (myself) would say 60 watts is a good minimum.

This board was dead when I bought it, got it for like a dollar on ebay, so if I can't revive it, I won't lose any sleep over it.

So, I am planning on using Panasonic FR caps for almost all of the capacitors (the obviously bad ones are G Luxons at 2700μF 6.3V, but I think I should replace all of them). But, the board has seven Teapo A3 1000μF 6.3V capacitors on it. I happen to have enough capacitors on hand to complete the job using either Nichicon HZ series or Nichicon L8 polymer series capacitors (both 1000μF 6.3V). So, since I have them on hand, I would like to save a little money and use them.

Both would be MASSIVE overkill compared to the original caps, but shouldn't be a problem. HZ is the lowest ESR, highest ripple current, electrolytic available, and the pollies are even better. BTW, A3 is not the Teapo's series, Teapos use a 2 letter series code like SC.

It seems like there is a bit of a debate on using polymer caps in place of wet electrolytics. Some say go down in voltage or capacitance, others say keep the specs the same unless installing near the VRM. I'm just really confused which would be the better choice. Should I use the Nichicon HZ's and save the L8's for another project, or for longevity's sake should I go ahead and put the L8's on the board?

Voltage is simple, Voltage needs to be at least the highest voltage the cap is going to see. If it's on a 5 volt rail, 6.3 volts is the lowest you can go. If it's on a 12V rail, 16V is the lowest you can go. If it's in the CPU VRM out, it will never see more then 2 volts, so you can use 4V or even 2.5 volt caps. If you're unsure, either use the same voltage rating as the original caps, or measure the voltage.

As far as capacitance goes, if the cap is anywhere other than a VRM out, use the same value as the original and you'll never go wrong. If it is on the CPU VRM out, ESR is more important than capacitance. If given the option, and you can fit the same value, do so. Otherwise, it's usually safe to go lower or slightly higher, assuming you're going from electrolytic to polymer.

Many manufacturers will make the same board with some having all electrolytics in the VRM, all pollies, or a mix of elec. and polly. When this is done it's quite common for the pollies to be half the capacitance of the electrolytics. You should always shoot for a minimum of about 3300uf of total capacitance, 5000uf is better. Too high and you risk blowing out mosfets with elevated inrush currents, but you'd have to get pretty high before that would be likely. Mind you, this applies for P4 class CPUs, and has been extrapolated from a P4 VRM chip application note, your board uses Athlon/Athlon XP CPUs, so although the above SHOULD apply, Your mileage may vary. I'm not sure that I've ever seen an Athlon era board with stock polymers, probably because the CPUs didn't require that the ESR/ripple be at polly levels, and the cost of pollies at the time was about 10 times the cost of electrolytics.

Opinions, commentary, and advice would be greatly appreciated for this confused newbie. Thanks in advance.

Yours,
Justin

[ratdude747]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Here's a rule of thumb for poly mods:

Halve the Capacitance for VRM caps, otherwise match the capacitance.

Granted, poly mods still may take some experimentation if a known working combo isn't already recorded, such anything topcat sells a poly kit for or that somebody else on the forum has done and confirmed.

PS- Athlon CPU's do run a tad warm... not as bad as many P4's, but much more than a PIII.

[jpyerry]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Right then, thank you for the comments.

If A3 is not the series for the Teapos, the only other identifier would be SM, could that be the series of Teapo I have on this board? I don't believe any of these capacitors are VRM caps, they are mostly located between the PCI slots and there is one near the DIMM slots and one more above the AGP slots.

I have not yet decided on a case for this board, I want to see if I can get the board working before I dress it out as a full PC. I am planning on using it as a Windows XP box. Should I get it going again, I will probably put it in a mini-tower or mid-tower ATX case from either Cooler Master, Lian-Li, or Silverstone, but I don't have my heart set on a particular case yet. I am planning on using a spare 450 Watt PC Power & Cooling PSU that I have kicking around. As for CPU cooling, I have a Swiftech MCX-462+ CPU cooler that I would like to use, haven't decided on a fan for it yet.

I am planning on buying a Hakko-FX888D soldering iron with a couple of extra sizes of chisel tips. I know the "D" model is pretty new, but it seems like a lot of people like the original FX888, so I am hoping that the digital will be a welcome addition. Do people find these irons are adequate for motherboard recapping?

So, since I do not believe these are VRM caps and I have the correct replacement in both poly and HZ. I think I am going to give the polymer capacitors a go, partially because the HZ's are ever so slightly taller than my PCI slots and because I actually have more of them, plus it seems like the HZ's are getting rarer. If worse comes to worst, I can always swap them out with the HZ's.

It will probably be a couple more weeks before I execute the recapping, but I will let everybody know how it goes.

Thanks for the comments, it is appreciated.
Justin

[retiredcaps]

Re: Opinions on whether I should use traditional electrolytics or polymers?

I am planning on buying a Hakko-FX888D soldering iron with a couple of extra sizes of chisel tips.

I have the FX-888 with a 3.2mm chisel tip that I use for desoldering. I mainly use the 1.6mm chisel tip for "everyday" use.

[jpyerry]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Thanks for the remark on my choice of the Hakko, I made my choice by watching videos on the eevblog.com, and while I love Dave Jones (I can credit him for rekindling my interest in electronics), I think he sometimes hypes one brand over another; not that I think he is being dishonest (in fact, I find he can be brutally honest), I think we all just tend to fawn over the things we really like.

Incidentally, since it would seem that my choice of using the Nichicon L8's or Nichicon HZ's might be overkill. Is there another capacitor out there that would be a good choice for a 1000μF 6.3V 8mm diameter, <15mm height, 3.5mm LS capacitor that I should consider should I change my mind over the next few weeks?

And, sorry for the barrage of questions, I just really want to get this right.

Justin

[retiredcaps]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Thanks for the remark on my choice of the Hakko, I made my choice by watching videos on the eevblog.com, and while I love Dave Jones (I can credit him for rekindling my interest in electronics),

I decided to invest in the FX888 after watching his LED hack vblog. Normally, I don't solder much but the price difference between your ebay 936 clone of dubious quality and the FX888 was a justifable $30 (to me).

In addition, after seeing some of the potentially internal wiring problems of the clones, I didn't want to burn down my house for the sake of $30.

I fully expect this soldering station to last me a lifetime not withstanding the tips which will eventually wear out.

Before the FX888, I was using sort by lowest price ebay 40W irons. They worked well for a while.

PS. I also love the blue/yellow color scheme.

[Topcat]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Honestly, I don't encourage polymodding unless its an unusual piece of hardware that will require extreme service/lifespan in extreme conditions, such as industrial applications or server uses. There is always an element of risk involved when using polymer caps in place of lytics, and for a run-of-the-mill home grade system, good brand lytics will more than carry the system through the remainder of its useful lifetime, and not have to worry about the potential of instabilities or other strange quirks that polymodding can present.

Of course for the sake of experimentation, go for it....but just to revive some entry level motherboard or video card, just go with exact replacement lytics and be done with it.

[LLLlllou]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Right then, thank you for the comments.

If A3 is not the series for the Teapos, the only other identifier would be SM, could that be the series of Teapo I have on this board?

Pretty likely, see attached.

I don't believe any of these capacitors are VRM caps, they are mostly located between the PCI slots and there is one near the DIMM slots and one more above the AGP slots.

VRM stands for Voltage Regulation Module, the main one (and what is usually being referred to when "VRM" is used) is for the CPU, but there are others. One for the RAM, one for the AGP or PCI, One for the chipset, depends on what chips are used. All have similarities an peculiarities.

[jpyerry]

Re: Opinions on whether I should use traditional electrolytics or polymers?

Well guys, I screwed it up. I decided to go ahead and try recapping the board with my Radio Shack iron (I got antsy and couldn't wait any longer) and in desoldering one of the caps, I managed to fracture one of the through hole plates and somehow managed to burn through part of the solder mask, I think the soldering iron actually got too hot. The cap is firmly in place though, I think some of the solder might have stuck. So, I guess it is possible that the board may still work, I am still waiting for the CPU to arrive in the mail, so that I can test it. Oh well, like I said, this was my garbage board and I learned my lesson about attempting to do this with a cheapo soldering iron, I will have the correct tools the next time I attempt this.

Yours,
Justin