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Recapping Capacitor List

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First post, by AppleSauce

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Hi so I've been working up towards recapping an Abit bf6 motherboard and an AOpen Z350-A PSU.
I've made a list of caps , would these be a good bet or should I get some other caps?

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Reply 1 of 93, by Deunan

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I see you've picked Panasonic caps for the PSU, this is their low-ESR series? You might want low ESR caps on the outputs (these are usually 1000uF+ caps), doesn't make a huge difference but can help with ripple. It would also be good to upgrade them to 105C but unless the PSU will be loaded a lot, and/or you intend to slow the fan down to lower the noise it makes, 85C will do. Primary side capacitors could also benefit from going to 105C if the PSU is running hot.

Not much point in going with expensive low ESR caps on the mobo, won't hurt but there's next to no benefit. Also no point in 105C caps there, if you get a lot of heat in the case then the problem isn't capacitors but poor airflow in general.

Reply 2 of 93, by AppleSauce

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Deunan wrote on 2021-10-11, 10:00:

I see you've picked Panasonic caps for the PSU, this is their low-ESR series? You might want low ESR caps on the outputs (these are usually 1000uF+ caps), doesn't make a huge difference but can help with ripple. It would also be good to upgrade them to 105C but unless the PSU will be loaded a lot, and/or you intend to slow the fan down to lower the noise it makes, 85C will do. Primary side capacitors could also benefit from going to 105C if the PSU is running hot.

Not much point in going with expensive low ESR caps on the mobo, won't hurt but there's next to no benefit. Also no point in 105C caps there, if you get a lot of heat in the case then the problem isn't capacitors but poor airflow in general.

Honestly I'm a bit of newbie when it comes to capping boards , so if you think I should change em then I'll get the 105c caps for the psu and cheaper caps for the motherboard.
I do plan on having a build with all the slots filled , so like 1 agp card plus 6 pci cards , I guess the 105c caps should help then?

Reply 3 of 93, by Deunan

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In PSU 105C capacitors vs 85C ones is always better, but not always required or cost-effective. In my experience the output filters die first, then the smaller ones (not all, but best to change all anyway since it's cheap), and the big input caps last. Unless the big ones were poor quality or too close to heatsink of the switching transistor(s) - but that usually shows. Still, they sometimes do vent slowly without any external signs of damage so without a meter to test them in-circuit it's probably easier to just replace anyway. Do make sure the new caps will fit though, 105C or low-ESR ones might be bigger than what was already in there so that might also limit your choices.

Re-capping old & tired PC PSUs is usually a good idea, but recapping in general should not be done "just because". This is often as useful as adding magnets to car air intake for power boost. And if you have never recapped a mobo I'd say train a bit first because you can easily cause more damage than good if your skills or tools are not up for the job.
Inspect the mobo and replace any caps that have clearly failed - bulged, vented or leaked. If the cap is part of a group, replace entire group, chances are other ones are no good too. The ones that usually go are close to CPU socket and AGP/PCI-E slot. If nothing seems out of place just leave them all be, recap PSU and see if that solves any stability issues you've had. If not, then consider recapping the mobo and/or the GPU.

Reply 4 of 93, by AppleSauce

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Deunan wrote on 2021-10-11, 13:03:

In PSU 105C capacitors vs 85C ones is always better, but not always required or cost-effective. In my experience the output filters die first, then the smaller ones (not all, but best to change all anyway since it's cheap), and the big input caps last. Unless the big ones were poor quality or too close to heatsink of the switching transistor(s) - but that usually shows. Still, they sometimes do vent slowly without any external signs of damage so without a meter to test them in-circuit it's probably easier to just replace anyway. Do make sure the new caps will fit though, 105C or low-ESR ones might be bigger than what was already in there so that might also limit your choices.

Re-capping old & tired PC PSUs is usually a good idea, but recapping in general should not be done "just because". This is often as useful as adding magnets to car air intake for power boost. And if you have never recapped a mobo I'd say train a bit first because you can easily cause more damage than good if your skills or tools are not up for the job.
Inspect the mobo and replace any caps that have clearly failed - bulged, vented or leaked. If the cap is part of a group, replace entire group, chances are other ones are no good too. The ones that usually go are close to CPU socket and AGP/PCI-E slot. If nothing seems out of place just leave them all be, recap PSU and see if that solves any stability issues you've had. If not, then consider recapping the mobo and/or the GPU.

The power supply is apparently new old stock and was never used , its just that it suffered from the capacitor plague from the 90s , some caps are bulged which is why I want to replace them.
The mobo has bulged caps as well so I've got no choice , I have to replace them too.

Reply 5 of 93, by Matth79

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Those 1000uF 10v are astonishingly expensive... are the 16V ones any larger, if not you could substitute those. Oops, misread, those are 100 not 1000

Also, trying to figure out what would need 10V caps on a motherboard
The ATX PSU delivers 12V (16V caps), 5V (6.3V caps, 10V could be there), 3.3V (maybe 4V caps, otherwise 6.3V), and the board generates core and VRAM voltages
SDRAM being 3.3V and CPU Vcore being max 3.5V

Last edited by Matth79 on 2021-10-11, 14:25. Edited 1 time in total.

Reply 6 of 93, by AppleSauce

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Matth79 wrote on 2021-10-11, 14:16:

Those 1000uF 10v are astonishingly expensive... are the 16V ones any larger, if not you could substitute those. Oops, misread, those are 100 not 1000

Also, trying to figure out what would need 10V caps on a motherboard
The ATX PSU delivers 12V (16V caps), 5V (6.3V caps, 10V could be there), 3.3V (maybe 4V caps, otherwise 6.3V), and the board generates core and VRAM voltages

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Here are the voltage values if it helps.

I Essentially got the motherboard for free from a friend and I only paid like 30 aud shipping included for the power supply. So I'm willing to spend a bit more for caps if it means the supply is generally reliable.

Reply 7 of 93, by Matth79

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If the 1000uF 10V are for CPU Vcore, then you could drop them to 6.3V models, I just can't think of anything inbetween 5V and 12V that would be on a motherboard.
CPU Vcore would need to be low ESR, so maybe in the original, 10V caps had better ESR?

Reply 8 of 93, by AppleSauce

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Matth79 wrote on 2021-10-11, 14:29:

If the 1000uF 10V are for CPU Vcore, then you could drop them to 6.3V models, I just can't think of anything inbetween 5V and 12V that would be on a motherboard.
CPU Vcore would need to be low ESR, so maybe in the original, 10V caps had better ESR?

Here's my jank diagram

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Reply 9 of 93, by AppleSauce

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The 1,2,3 mystery cap values i only figured out after i took them out of the board since they were blocked from view by other caps or hearsinks.

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Also I might try and make a better diagram on the pc since my hand written scribbles are spectacularly awful , sorry about that.

Reply 10 of 93, by Deunan

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Weird, the PSU does look unused but it has bulged caps. That happens only when power is applied, so perhaps it has clocked a few hours but not more than that.
So, looking at the photo, the output filtering capacitors are on the left. Bulged, some of them at least, replace all. As I've said try to find low-ESR or 105C that will fit - if you can. On the right, the big input caps, look OK-ish but I would replace them because TEAPO.

The rest can be OK or not but since some bulged, better to replace with known good ones. You don't want PSU failure taking a mobo with it just because one somewhat critical electrolytic filtering power to the PWM controller has failed. If I was doing that, I would replace all except the input caps, and test those to see if still good. But not CHEAPO brand, these have to go even if they seem good right now.

Reply 11 of 93, by AppleSauce

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Deunan wrote on 2021-10-11, 15:03:

Weird, the PSU does look unused but it has bulged caps. That happens only when power is applied, so perhaps it has clocked a few hours but not more than that.
So, looking at the photo, the output filtering capacitors are on the left. Bulged, some of them at least, replace all. As I've said try to find low-ESR or 105C that will fit - if you can. On the right, the big input caps, look OK-ish but I would replace them because TEAPO.

The rest can be OK or not but since some bulged, better to replace with known good ones. You don't want PSU failure taking a mobo with it just because one somewhat critical electrolytic filtering power to the PWM controller has failed. If I was doing that, I would replace all except the input caps, and test those to see if still good. But not CHEAPO brand, these have to go even if they seem good right now.

Is it safe to use low esr for all the caps because I heard some people say that some might not be low esr depending?

Also would it be prudent to buy extra caps in case some that I buy turn out bad , I'm guessing they don't test all of them?

Reply 12 of 93, by dionb

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Deunan wrote on 2021-10-11, 15:03:

Weird, the PSU does look unused but it has bulged caps. That happens only when power is applied, so perhaps it has clocked a few hours but not more than that.

Not necessarily. Applying power speeds up the processes, but bad electrolyte can degrade spontaneously over a few decades as well. I've had NOS motherboards that were 100% confirmed never to have been out of their sealed packaging since manufacture in 2002 that still had caps bulging all over the place.

Reply 14 of 93, by Deunan

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Low-ESR really only matter in switching-mode PSUs (so like this one) and mostly only on output, unless somebody really pushed the primary side due to limited space or higher operating temperature. Low ESR caps will have lower losses with high current spikes, so will heat up less and also provide somewhat less ripple on output. That being said in most cases a brand new modern "normal" ESR capacitor will also do, these PSUs were made to be cheap. It's not a must, but if the price difference is say 30$ total and the amount of work you put in the the same, then why not upgrade. This is NOS power supply (even if nothing fancy), I think it warrants better caps, I'd go for it. It looks like you can get taller caps for secondary side, except maybe if some are under that add-on fan speed regulator.

So, in short, low ESR electrolytics are rarely required as such, but except some rare cases (like vacuum tube rectifiers) never hurt. The main reason I suggested 105C or low ESR (or both) for output is these PSUs can have hot spots due to output wires being in the way, and these capacitors suffer more than other ones and tend to go first. But even standard, modern 85C electrolytics of good brands should last years, so don't overdo it if the ones you find are more than just a bit more expensive.

As for bulging with no power, I've never seen it myself (it takes quite some internal pressure to bulge a cap) but then I haven't actually seen a lot of NOS PCBs from that era, so I guess I stand corrected. Good to know.

Reply 15 of 93, by AppleSauce

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Here is what it looks like under the extra board

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So basically anything near the output where the atx connector is should be low esr then?

Reply 16 of 93, by Deunan

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Yes, all the ones next to output wires are good candidates for low ESR replacement. Just FYI, that glue that keeps them attached to PCB can be pretty strong, you might need to cut that a bit first with a sharp knife tip or something. No need to glue it back again though, it's just to protect the caps from being twisted off by the cables but unless you pull a lot on those it will not happpen.

Reply 18 of 93, by AppleSauce

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Deunan wrote on 2021-10-11, 16:40:

Yes, all the ones next to output wires are good candidates for low ESR replacement. Just FYI, that glue that keeps them attached to PCB can be pretty strong, you might need to cut that a bit first with a sharp knife tip or something. No need to glue it back again though, it's just to protect the caps from being twisted off by the cables but unless you pull a lot on those it will not happpen.

Yeah I had to chip away some to read the values of some caps its bloody strong and its really annoying.

Reply 19 of 93, by retardware

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Deunan wrote on 2021-10-11, 10:00:

Not much point in going with expensive low ESR caps on the mobo, won't hurt but there's next to no benefit.

Really?
I always thought, in particular where the DC-DC converters are, low ESR would be helpful.

Deunan wrote on 2021-10-11, 16:08:

vacuum tube rectifiers

Not vacuum, but beautiful 😀