voodoo1907 wrote on Today, 12:22:
Thanks for the detailed answer. How about the NOS DELTA DPS-250GB 250W? It’s old and only 250W, but it looks like it’s made by a decent manufacturer, and it seems to have powerful enough rails — +5V 25A, +3.3V 20A, with a combined maximum of 150W.
Thumbs up for the Delta from me.
Being as old as it is, though (despite being NOS), you should still open it and check for bad/bulging caps.
Just curious how much is it priced at, being NOS and all.
Normally, similar OEM PSUs from that era can be found on ebay for around $15 shipped in the US.
I personally always got mine used and just refurbished them myself - open, clean dust from inside, inspect and/or lubricate the fan, and recap in most cases (even when the caps were OK)... so that way, I know I'll have a reliable PSU I won't have to worry about anymore.
By the way, that Chieftec GPS-450A is also made by Delta (UL number is E131881... which leads back to Delta) - just a much newer platform that probably won't deal too well if used with a motherboard that draws more power from the 5V rail than the 12V rail.
dionb wrote on Today, 11:35:
Next the question is how much current your system uses on that line. A Duron 1300 has a 60W TDP. Let's also assume the 7500LE only gets its power from 5V (ATX power is a bit more complicated, but always safe to assume worst-case). Its TDP is 23W. I always add a 10W 'fudge factor' for what the chipset and other devices might use on top of that so we come to a total of 93W. Divide that by five for the current at 5V: 18.6A.
Excellent advice and calculation there. This is how I normally do it as well.
The 10 Watt "fudge factor" can sometimes be larger and sometimes smaller. Usually depends on what the motherboard is using to power the two next most power-hungry things after the CPU: the Northbridge and the RAM. I usually dedicate anywhere from 10 Watts to 20 Watts for those, typically judging by the side of the NB's heatsink and # of RAM sticks installed. And if I really want refinement, I'll do a quick continuity check on various MOSFETs on the motherboard in question to try and determine what rail powers the NB and what rail powers the RAM (it can be 3.3V or 5V or a mix of the two.)
That said, 20 Amps on the 5V rail should be good enough for that system, though with no headroom for adding other hardware that draws heavy from the 5V rail (e.g. swapping the Radeon 7500 with a 9500/9700/9800.)
dionb wrote on Today, 11:35:
Moreover, the PSU is still at least two decades old, so it's fairly likely it won't be performing as well as when it was new either.
No such thing exists.
Unless the electrolytic capacitors are severely degraded - i.e. failed - then there's nothing that would make an old PSU not perform as good as new.
Please stop the fearmongering that old PSUs = always unsafer to use.
There are old ones (though not too many) that were built great with top-tier Japanese caps and are essentially bullet-proof.
Astec (careful not to confuse this with Bestec) is one of these. It's not a brand that was sold stand-alone, but rather only found in OEM PCs, like Gateway, HP, and etc. LiteON and Delta also sometimes had models that were built like that.
That said, even the PSUs that weren't built with the best brands of caps are sometimes still OK (if not better) to use with a retro PC than a new PSU with a weak 5V rail that may struggle to power the old hardware properly (or at all.)
dionb wrote on Today, 11:35:
Now, a new quality power supply will always be a safer bet than an old period-correct one
Sure. But again, the main issue is finding a modern good quality PSU that has a strong 5V rail.
dionb wrote on Today, 11:35:
I'm not convinced Point of View makes quality power supplies. In fact, they don't make any themselves, just slap their label onto an ODM's design (PoV seems to use Casing Macron).
If it's a Casing Macron, that would be a good thing! Well, IME, anyways. 😀
You can check by the UL number, if that's visible on the label. (Though probably worth noting that a few PSU manufacturers did cheat and put other manufacturer's UL number.)
Macron Power is E199529
I do actually hunt out for old Casing Macron PSUs as they make really good retro PC PSUs... but not before a full recap, of course.
Depending on your skill level and/or how much time and effort you're willing to spend, such PSUs may or may not be worthwhile to you. Just FYI, recapping PSUs is a lot easier than recapping motherboards, though still a tedious and time-consuming process. You just won't struggle as much with the soldering, as much as you would with extracting the old caps from tight spaces.
dionb wrote on Today, 11:35:
in fact I just checked on badcaps.net and Casing Macron is all over there. General consensus seems to be decent design but substandard components, both caps and rectifiers.
Just the caps are usually what's terrible about these PSUs. The rest is anywhere from OK to very good, at least considering their age and application.
I have a few posts there (on badcaps.net) specifically detailing a few Macron units. All three are very capable of powering a 5V-heavy PC as well as 12V-based PCs. So they are kind of universal for retro rigs.
In fact, the current PC I'm posting from right now has a recapped Macron Power PSU.
dionb wrote on Today, 11:35:
If you want an old PSU, get a quality one with sufficient specs (Fortron Source Power (FSP) is my go-to for period supplies with beefy 5V lines) but be aware of the age, check caps and always test first with a dummy load (eg. an old HDD with bad sectors) so if it blows, it doesn't take anything valuable with it.
Old FSP PSUs (the ones that have a 5V rail rater higher than the 12V rail) are indeed good for 5V-heavy systems.
However, these, just like Macron Power mentioned above, also often suffer from bad caps. So if you get one, I'd most certainly recommend a recap before using, even if everything looks "OK".
Actually, there's one flaw on old FSP PSUs that some of you should beware about, and this is actually present on many PSUs from that era: the 5VSB circuit uses a 2-transistor self-oscillating circuit with a critical "run" electrolytic cap. When this cap fails really badly (and it can happen on some of these, depending on which 2nd tier brand of capacitors they used), the 5VSB can grossly increase over spec and take out the motherboard's SB or SIO chip, along with some other hardware too.
Unfortunately, this is not something that would show up when you only test the PSU with an old HDD or CDROM or similar. For that, you need a multimeter and check the voltage of the 5VSB rail right after powering up the PSU.
But again, this issue affects not only FSP, but also a number of other quality brands, like Delta and Bestec.
Actually, the most infamous one with this issue is the Bestec ATX-250-12E model - it's a guaranteed motherboard killer. The good news is that pretty much all of them are dead now, so you'd be hard-pressed to find one anymore. But mentioning this just in case anyone does. Now the next revision of this model - the ATX-250-12Z does not have this problem and uses an entirely different circuit for the 5VSB that is comparably safe to modern PSUs'.
dionb wrote on Today, 11:35:
If you don't want that hassle, go for a new PSU, but get it from a reputable brand - and even there check the specific model (Seasonic, here's looking at you). I always prefer to buy products branded by the actualy manufacturer, not relabeling brands (such as Corsair, Be Quiet, EVGA etc.). So good brands I would recommend are things like Super Flower, FSP (yes, they're still around) and Seasonic (as long as you avoid the duds). Even then, find independent reviews of specific models - so ones where PSUs of different brands are compared and your preferred PSU gets at least some criticism. Marketeers flood the social media channels with sponsored content that tells you absolutely nothing other than what the manufacturers want you to hear. Ignore all such content.
Well said.
I personally wouldn't avoid the relabeling brands (Corsair, EVGA, Be Quiet, Cooler Master, and etc.) so long as a legitimate review (one with a break-down of the components inside the PSU as well as detailed load performance) is available for the unit you're looking at. In particular, pay attention to the capacitor brands used. Even many of the legitimate reviews will dismiss less-than-great capacitor brands as "OK" in a budget-tier class PSU (and sometimes even in a high-end class too.) For me, that's a NO-NO. The brand (and thus quality) of the electrolytic capacitors is one of the main factors in how long a PSU will last. The Japanese brands (Rubycon, United Chemicon, Nichicon, and Panasonic) are at the top. Below them, "2nd tier" caps like Teapo, Taicon, Elite, OST, and Samxon may not be as good, but they will more than likely outlast the warranty of the unit, and often at least make it to the 10 year mark. Then there's the lower-end of the "2nd tier" of caps - e.g. CapXon and Ltec - these are usually similar to the caps in the abovementioned 2nd tier, but with a little more unpredictability... so may fail much sooner. And then below the 2nd tier of caps mentioned above, it's an ocean of brands - most of them wildly unpredictable in how long they will last.
