VOGONS


Reply 41 of 47, by Vaudane

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TheMobRules wrote on 2020-08-02, 21:55:
When it comes to brands it's easy: Nichicon, Rubycon, United Chemi-con (also known as Nippon Chemi-con) or Panasonic. […]
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pentiumspeed wrote on 2020-08-02, 21:25:

Still no answer here yet some of you said that worked well, please provide the brand and series of these capacitors (especially electrolytic low ESR capacitors)?

When it comes to brands it's easy: Nichicon, Rubycon, United Chemi-con (also known as Nippon Chemi-con) or Panasonic.

As for specific series, it really depends on the component you are trying to recap and its age. But as a general guideline:

  • Pre-2000 power supplies: Nichicon UPJ/UPS, Rubycon YXF, UCC LXV/LXY
  • 2000-2005 power supplies: Nichicon UPW, Rubycon YXG, UCC LXZ/KY, Panasonic FC
  • Pre-S7 MB: in most cases anyting rated 105C should work, Intel used the old equivalent to Nichicon UPM on a lot of their boards
  • Socket 7, Slot 1: Nichicon UPW or equivalent
  • S370, Socket A: Panasonic FM, Nichicon UHW, Rubycon ZLQ
  • S478/775, 754/939: these usually have ultra-low ESR caps, you'll probably need to use polymers here

Series to avoid: Nichicon HM/HN, UCC KZG/KZJ as these are almost guaranteed to fail prematurely (I don't think they are in production anymore though)

Again, it's better if you provide specific examples of what you need to replace, I'm just basing this on past experience but the options could change depending on the board. If you want to be certain it's worth to put some effort on finding the datasheets of the caps you are replacing (if possible) and browse Mouser or Digi-Key for japanese caps with similar specs.

Another question on this actually since you look like you have the know. I have a motherboard that uses some small value lytics near the CPU, two 25v10u and a 25v22u. Their footprint means they cannot be replaced by polymer, but ceramics exist with that footprint. Is there any reason a ceramic couldn't replace a lytic? I know about microphonics and the derating at higher voltages, but since the motherboard shouldn't see any higher than 12V and thus 25V is already overkill, I can't think of any other reasons.

Reply 42 of 47, by canthearu

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SETBLASTER wrote on 2020-08-27, 06:30:

so for PSU built in the athlon xp /pentium4 era

i should replace with LOW ESR caps? or can i use Normal ones?

Computer PSUs normally use low ESR capacitors, but usually not ultra low esr capacitors. Like computer motherboards, try to match what the existing caps are in terms of ESR, voltage, capacitance and Ripple Current.

Do not polymod a PSU, it doesn't normally work.

Reply 43 of 47, by canthearu

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Vaudane wrote on 2020-08-28, 15:39:

Another question on this actually since you look like you have the know. I have a motherboard that uses some small value lytics near the CPU, two 25v10u and a 25v22u. Their footprint means they cannot be replaced by polymer, but ceramics exist with that footprint. Is there any reason a ceramic couldn't replace a lytic? I know about microphonics and the derating at higher voltages, but since the motherboard shouldn't see any higher than 12V and thus 25V is already overkill, I can't think of any other reasons.

Normally, the small caps are just fine and don't need replacing.

I would be wary of replacing them with ceramic capacitors, their characteristics are vastly different.

Reply 44 of 47, by TheMobRules

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Yeah, for PSUs of the P4/XP era stuff like Nichicon UPW should be fine, low ESR but not "ultra-low". I have read about several instances of people attempting polymods on power supplies from that era and they usually have problems like canthearu said (due to the feedback loop being affected I believe).

canthearu wrote on 2020-08-28, 15:52:

Normally, the small caps are just fine and don't need replacing.
I would be wary of replacing them with ceramic capacitors, their characteristics are vastly different.

+1

If you're really, really worried about those small caps or they are of a known garbage brand, just replace them with Japanese electrolytics, pretty much anything rated 105C will work for those.

Certain people underestimate the lifespan of good electrolytic caps, thinking they will dry out after a couple of years. But if you use adequate replacements of reputable brands, I bet they will even outlive some of the other components, unless we're talking about a really rough environment with lots of heat.

Personally I wouldn't bother with polymodding unless there is a specific ultra-low ESR requirement, otherwise I try to stick to replacements that are as close to the original specs as possible (unless there are known problems with the original design). But I know this goes against what many YouTubers do with their "future-proofing" techniques... many half-truths or outright lies spawn out of those videos.

A while back I saw a video of a dude refurbishing an old Amiga power supply, and after replacing the caps he applied lots of hot glue over them. He claimed that the manufacturer also used glue originally because the coil vibrations could break the solder joints, which is a bunch of horseshit. While the coils do vibrate, the glue is applied to hold the caps in place for the wave soldering during the manufacturing process and possibly to prevent noise from vibrations. But for a manual recapping job, if you solder the caps flush to the board, this is a non-issue.

Reply 45 of 47, by Vaudane

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canthearu wrote on 2020-08-28, 15:52:
Vaudane wrote on 2020-08-28, 15:39:

Another question on this actually since you look like you have the know. I have a motherboard that uses some small value lytics near the CPU, two 25v10u and a 25v22u. Their footprint means they cannot be replaced by polymer, but ceramics exist with that footprint. Is there any reason a ceramic couldn't replace a lytic? I know about microphonics and the derating at higher voltages, but since the motherboard shouldn't see any higher than 12V and thus 25V is already overkill, I can't think of any other reasons.

Normally, the small caps are just fine and don't need replacing.

I would be wary of replacing them with ceramic capacitors, their characteristics are vastly different.

TheMobRules wrote on 2020-08-28, 16:51:
Yeah, for PSUs of the P4/XP era stuff like Nichicon UPW should be fine, low ESR but not "ultra-low". I have read about several i […]
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Yeah, for PSUs of the P4/XP era stuff like Nichicon UPW should be fine, low ESR but not "ultra-low". I have read about several instances of people attempting polymods on power supplies from that era and they usually have problems like canthearu said (due to the feedback loop being affected I believe).

canthearu wrote on 2020-08-28, 15:52:

Normally, the small caps are just fine and don't need replacing.
I would be wary of replacing them with ceramic capacitors, their characteristics are vastly different.

+1

If you're really, really worried about those small caps or they are of a known garbage brand, just replace them with Japanese electrolytics, pretty much anything rated 105C will work for those.

Certain people underestimate the lifespan of good electrolytic caps, thinking they will dry out after a couple of years. But if you use adequate replacements of reputable brands, I bet they will even outlive some of the other components, unless we're talking about a really rough environment with lots of heat.

Personally I wouldn't bother with polymodding unless there is a specific ultra-low ESR requirement, otherwise I try to stick to replacements that are as close to the original specs as possible (unless there are known problems with the original design). But I know this goes against what many YouTubers do with their "future-proofing" techniques... many half-truths or outright lies spawn out of those videos.

A while back I saw a video of a dude refurbishing an old Amiga power supply, and after replacing the caps he applied lots of hot glue over them. He claimed that the manufacturer also used glue originally because the coil vibrations could break the solder joints, which is a bunch of horseshit. While the coils do vibrate, the glue is applied to hold the caps in place for the wave soldering during the manufacturing process and possibly to prevent noise from vibrations. But for a manual recapping job, if you solder the caps flush to the board, this is a non-issue.

I think that about answers my question thanks guys. You got it in one with the lifetime statement. I've read there is little tangible benefit to polymodding a PIII board, but I wanted to do it for longevity.

Should be cheaper too... Time to get me some Nichicon UHW series.

Reply 46 of 47, by pixel_workbench

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I recapped a few P3 and P4 boards using modern low ESR Nichicon or Panasonic electrolytics, and haven't had any issues. Usually just make sure to use the rated voltage, capacitance, and size of the replacement capacitors no less than the original. These boards will not be run 24/7 for years, and will not be placed in a vintage steel box with crappy airflow, not plugged into flaky old power supplies, and not feeding the most power hungry CPU that fits, overclocked to the max. So I don't bother polymodding or looking for vintage ultra low ESR electrolytics. If I was working with A64, Preshot or newer boards, then I'd probably go with polymers.

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Reply 47 of 47, by gdjacobs

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TheMobRules wrote on 2020-08-28, 16:51:

Yeah, for PSUs of the P4/XP era stuff like Nichicon UPW should be fine, low ESR but not "ultra-low". I have read about several instances of people attempting polymods on power supplies from that era and they usually have problems like canthearu said (due to the feedback loop being affected I believe).

Nichicon PW and PM are great general duty caps.

TheMobRules wrote on 2020-08-28, 16:51:

Personally I wouldn't bother with polymodding unless there is a specific ultra-low ESR requirement, otherwise I try to stick to replacements that are as close to the original specs as possible (unless there are known problems with the original design). But I know this goes against what many YouTubers do with their "future-proofing" techniques... many half-truths or outright lies spawn out of those videos.

Poly modding is sometimes the best option if you're replacing HM, HZ, MCZ, or other ultra low ESR caps, some of which are no longer easily available.

TheMobRules wrote on 2020-08-28, 16:51:

A while back I saw a video of a dude refurbishing an old Amiga power supply, and after replacing the caps he applied lots of hot glue over them. He claimed that the manufacturer also used glue originally because the coil vibrations could break the solder joints, which is a bunch of horseshit. While the coils do vibrate, the glue is applied to hold the caps in place for the wave soldering during the manufacturing process and possibly to prevent noise from vibrations. But for a manual recapping job, if you solder the caps flush to the board, this is a non-issue.

Wow, that's stupid. The coils are sometimes caulked or wrapped to reduce whine, but not caps. If they were vibrating enough to break solder joints, the noise would be godawful.

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