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Any sense buying modern PSU for old hardware?

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Reply 80 of 86, by CharlieFoxtrot

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Mike_ wrote on Yesterday, 05:52:

Hmm, would you think it'd be worth the effort to recap that Enermax, even though output seems to be fine or just wait and see? I'd actually like to have that in working condition as it's a pretty nice PSU otherwise, so it would be a lot more likely to see actual use than the Fortron.

What is worth is up to you, but I wouldn't trust those CEC caps holding up at all.

How did you measure the voltages, because just your basic "multimeter voltage" won't show you how the caps are working. You need to look at ripple and how "dirty" the voltages are and you need oscilloscope for that.

Example from real life: I just replaced caps on a 1980s 286 PSU. At first everything seemed to work just fine, but when I brought the system inside from workshop, the systems soon became very unstable and LCD screen in front of the case went haywire. I also smelled bad caps. Caps most likely started to puke their insides out when I started to use the system for longer periods of time and re-enwrgized them.

And guess what? Based on multimeter readings the voltages were still fine and completely in spec. As a matter of fact, even the capacitance of those leaked caps was in spec, only ESR was extremely high, like 5-8ohms for all the caps. Your basic voltage measurement doesn't necessarily show if something is already wrong. You notice it when your system starts behaving badly. Or smelling bad.

Ehh, it looks like there's lots of that yellow goo and even a couple of daughterboards with a bunch of small caps in them... If it's just a so-so PSU, I'd probably prefer not to spend the time for it.

It is up to you, but I wouldn't worry about the goo. It is often so brittle that you can just easily wiggle the cap off. And if not, you can cut it easily with exacto knife. It is not a problem or a hurdle.

And like I said before, just change the voltage rail filtering caps. Those small caps in the regulation and protection circuits are 99% chance just fine and stay that way for years. I personally change them for the most part, because with desoldering gun changing these caps is extremely fast if you have mapped them beforehand and you have the replacements at hand. I do it basically because it is not a significant effort at that point, not because I'm that much worried about those caps.

Reply 81 of 86, by Caesum

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Okay one last question then before I decide to buy. I found this cheap FSP Fortron that has pretty good 5V and 3.3V, but it says that it's an Active PFC one. Do you think it could work or should I ignore any active PFC PSU entirely?

Also another silly question, how do you find out if a PSU is non-active PFC? I wouldn't have guessed this one was an active one if it wasn't for this huge sticker on it lmao. I know good rule for me is to look for PSUs with beefy 3V and 5V but some modern ones have them good too and yet they are not recommended for retro hardware.

Reply 82 of 86, by appiah4

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Visual inspection of my whining ATX-400PNF PSU revealed one bulging 3300uf 10V Teapo cap. There is another 3300uf 10V and two 2200uf 16V Teapo caps right next to it, that I will also be replacing, just in case.

Reply 83 of 86, by shevalier

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Caesum wrote on Yesterday, 21:00:

Okay one last question then before I decide to buy. I found this cheap FSP Fortron that has pretty good 5V and 3.3V, but it says that it's an Active PFC one. Do you think it could work or should I ignore any active PFC PSU entirely?

Also another silly question, how do you find out if a PSU is non-active PFC? I wouldn't have guessed this one was an active one if it wasn't for this huge sticker on it lmao. I know good rule for me is to look for PSUs with beefy 3V and 5V but some modern ones have them good too and yet they are not recommended for retro hardware.

https://www.elektroda.pl/rtvforum/topic1329491.html
And the following topics

PSUs with APFC emerged in response to the significantly increased power demands of the AM2/S775 era and graphics cards such as the 8800 GTX.
As a result, they are more complex and were used in more demanding conditions.
Whilst a unit without an APFC has most likely been sitting on a shelf for the last 15 years, one with an APFC has most likely been in operation somewhere in an office for the entire 20 years since its release.

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

Reply 84 of 86, by tehsiggi

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appiah4 wrote on Yesterday, 23:07:

Visual inspection of my whining ATX-400PNF PSU revealed one bulging 3300uf 10V Teapo cap. There is another 3300uf 10V and two 2200uf 16V Teapo caps right next to it, that I will also be replacing, just in case.

Yeah, begone with them! PSUs are packed and hot, no happy life for a cap. And then the age on top of it.

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Reply 85 of 86, by Mike_

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CharlieFoxtrot wrote on Yesterday, 14:08:
What is worth is up to you, but I wouldn't trust those CEC caps holding up at all. […]
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What is worth is up to you, but I wouldn't trust those CEC caps holding up at all.

How did you measure the voltages, because just your basic "multimeter voltage" won't show you how the caps are working. You need to look at ripple and how "dirty" the voltages are and you need oscilloscope for that.

Example from real life: I just replaced caps on a 1980s 286 PSU. At first everything seemed to work just fine, but when I brought the system inside from workshop, the systems soon became very unstable and LCD screen in front of the case went haywire. I also smelled bad caps. Caps most likely started to puke their insides out when I started to use the system for longer periods of time and re-enwrgized them.

And guess what? Based on multimeter readings the voltages were still fine and completely in spec. As a matter of fact, even the capacitance of those leaked caps was in spec, only ESR was extremely high, like 5-8ohms for all the caps. Your basic voltage measurement doesn't necessarily show if something is already wrong. You notice it when your system starts behaving badly. Or smelling bad.

I know, I even included a picture of oscilloscope screen in previous page...

Reply 86 of 86, by Caesum

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Guys, I checked AKYGA site again for their PSU specifications and... It seems they are actually making Passive PFC units too. Look at this power supply:
https://www.akyga.com/products/3-power-supply … 1-420-420w.html

That's the PSU I was thinking about buying at the start of the topic before everyone suggested not trying this brand (I still won't buy it, I was just curious). Frankly I am surprised as I thought nobody makes passive PFC units anymore. Although they say it should be used with "current and next generation of platforms". Akyga is a Polish brand if anyone wonders.