I like the person doing "mmmmhhhh" and "aaahhh" on the background of the antec comparison, he wins the internet 🤣

Since the days of hot Athlons being fed through low voltages I've had a habit of buying Enermax units for the computers at work (if the budget allowed it).
Most of these still work, but they are useless for powering modern machines, so I kept a few for my retro rigs:

The pics are from a 465W (ATX12V ver. 1.2) model, this was shortly before power was moved to the 12V rail(s) and the -5V rail started to vanish.

@TELVM: Thanks for explaining PSU designs, I'm sure many of us learned a lot in this thread 😀

My pleasure 🤣 . ^ That Enermax looks well built. Decent input filtering with a MOV. APFC with a fine Rubycon bulk cap. Decent thick heatsinks & main trafo. Well sized caps & robust PI coils on output.

Just two details, there is a cement resistor close to the trafos:

^ These things get very hot (that's why they put a heat isolator between it and the trafos, the 'V' shaped thing in top view). And the fan looks cheap and tired after a decade. If the fan seizes, the PSU cooks itself and dies. A fresh decent fan wouldn't harm (if we cut-off the grill behind the fan, even better).

Also I see a lot of PCE-TUR caps, which is a suspicious brand. I wouldn't trust them after a decade.

Thanks for the info about the cement resistor, I already wondered what that was. Fortunately this PSU has a decent 92mm fan in the lid, so the resistor (and the transformators in the cramped middle part of the PSU) should get enough air flow.
You're right about the 80mm fan on the back though, I've had to replace these on several PSUs (they start to make very annoying noises when failing).
The PCE-TU(R/L) caps seem to be common in Enermax PSUs. To be honest, I expected something with a better reputation considering the price of these PSUs (~100 € when they were new).
One more question: What is on the vertical PCB shown in the fifth picture? Is it part of an active PFC circuit or something different?

5u3 wrote:

... Fortunately this PSU has a decent 92mm fan in the lid ...

Excellent, having two fans in the PSU improves cooling and reliability a lot. Fans in series increase the static pressure, which helps moving more air thru the cramped and aerodynamically restrictive innards of a PSU.

IMHO the best cooling solution for a PSU is two fans enfilading the heatsinks:

5u3 wrote:

... The PCE-TU(R/L) caps seem to be common in Enermax PSUs. To be honest, I expected something with a better reputation considering the price of these PSUs (~100 € when they were new) ...

Yep, makes no sense placing a top-notch Rubycon at the primary and then suspicious caps at the secondary. One can understand finding Teapos in unexpensive entry PSUs (you get what you pay after all), but things like those all-Fuhjyyu SmartPowers of the past, or finding CrapXons inside a $200 760i make little sense.

5u3 wrote:

... One more question: What is on the vertical PCB shown in the fifth picture? Is it part of an active PFC circuit or something different?

Yep that's the APFC circuit, the controller is a UCC3817 .

time to get another opinion from TELVM 🤣

What do you think of this AT psu? I don't see much input filtering and it appears that the 125/230v switch on the back is functional on this one...

edit:
in case this is a good psu, how about adding this filtering to the input?

Looks a bit cheap but there is always room for improvement. The transient filtering is lame, would be a good idea to use the real choke, X-cap and Y-caps from that daughterboard if you can shoehorn them in. Input caps are good Rubys, but don't trust the cheap brands in the output after two decades, better recap them.

thought so, I'll put is aside for when I get a stock of quality caps... plenty of room for the extra filtering board 😀
thanks TELVM!

I was "gifted" this Enermax 300W power supply by an old college classmate back in early November, and would like to know if it's OK to use it in my Socket 7 build; the generic PSU I'm using right now is over a decade old and showing signs of age - time to replace it.

(Sorry about the wall of pics, just trying to give as much detail as possible 😅 )

If everything looks good and proper then I'll use it; if not, then I'll just send it to the recycling center (my soldering skills are horrible and I don't know anyone around that can fix old PSUs like this).

I've got the EG301P-VE

Those PCE-TUR capacitors need to be replaced before you can use it. Don't chuck it, because you'll probably need the -5V voltage rail which newer PSUs lack, so if you can't re-cap it yourself, get someone to do it for you.

I think I have a list of the caps that need to be replaced somewhere around here. Let me know if you're interested, and I can give you a list of what parts you'd need from Digikey.

^ Looks decent enough to propel an SS7 but as said above those caps can't are untrustworthy.

Thank you mockingbird & TELVM, I'll just keep it in my spare parts box with a "must re-cap first" label until I can find someone that can do the job. I would also appreciate it if you can send me the parts list mockingbird, to keep it along with the Enermax.

In the meantime, will the SeaSonic SS-300ES be a good one to use?

JayCeeBee64 wrote:

... In the meantime, will the SeaSonic SS-300ES be a good one to use?

Sure, plenty enough for a SS7 system. Can't find pics of the 300's guts, but if this SS-500ES ain't much different:

http://translate.google.com/translate?sl=auto … %2F%3Flang%3Dru

It looks decent enough for a retrocomp. The output caps could be better but at least they'll be fresh.

Very interestingly they took readings of components' temps (in ºC):

^ The various inductors and the transformer are the hottest spots. Notice also the bridge rectifier temp ('41'), it would be hotter without a heatsink.

Excellent, thanks again TELVM. I'm off to get one 😀 .

I don't think that PSU has -5V.

Yes, it doesn't have -5V. Unfortunately, I don't have much of a choice: either use a well-known brand modern ATX PSU without it, or use one that has it from a brand I don't recognize (Startech, Apevia) or has a bad reputation (Coolmax). And finding one on eBay is a crap shoot as well. I'll simply take my chances with the SeaSonic (thanks for the concern, though).

Find an old Delta PSU from a P4 Dell tower. They're 20-pin, and they have -5V and are pretty good quality...

I misspoke... I just checked my Delta NPS-250KB (manufacture date of the 18th week of 2002), and it does not have the -5V rail.

My Enermax does though, and the PCB is very similar to yours.

Well mockingbird, after reading this thread here, I've changed my mind and decided to order the Startech ATXPOWER300 PSU (the specs can be found here). I'm hoping it is similar in build to their AT power supplies. Also, if possible, I'll open it and take some pics as soon as I get it. I'm also still looking for someone local that can do the re-capping of my Enermax EG301P-VB.

TELVM wrote:

No problem, the SS-300FS has a 30A +5V rectifier of TO-247 size, beefier than typical TO-220s. It can handle any Athlon Classic you throw at it 😎

I have a few of these Seasonic PSUs now and used one in an Athlon 64 3000 / Radeon 9800 Pro build... do you think it's up to it or will the 12v load be too much? Thanks and sorry for necropost 😀