Recommendation for Pentium II PSU

[ratdude747]

Re: Recommendation for Pentium II PSU

P.S: We prefer if you also attach the photos here, so they don't get lost in the future if the host goes down/deletes them...

This. Such a common problem, we even have a smiley for it:

[Per Hansson]

Re: Recommendation for Pentium II PSU

I would also suggest to reform the main capacitor to be nice to it if the unit has not been powered on for many years.
This can be done very easily by having a really small incandescent light bulb in series with the unit.
Say 15w or the smallest you can find that is rated for your line voltage.
Then don't try to start the unit: just connect mains to it and switch the power switch to the on position.
The 5VSB will still be up and so the unit will be reformed even without starting it...

P.S: We prefer if you also attach the photos here, so they don't get lost in the future if the host goes down/deletes them...

[Th3_uN1Qu3]

Re: Recommendation for Pentium II PSU

Yeah, you didn't win the capacitor lottery this time around. Recap the secondary side and you should be up and running.

[teknical]

Re: Recommendation for Pentium II PSU

Sorry for the delay, I have been busy.

I have an update, I just went ahead and bought the SeaSonic for $40. The guy spent half on shipping so I suppose you could say it was $20 and $20 on shipping.

Anyway, here are the insides. I think I see some bulging caps.

[momaka]

Re: Recommendation for Pentium II PSU

I was starting to wonder if we made you mad or something though!!

LOL!
Nah, this would be the last place on earth for anyone to drive me mad. If anything, more like the other way around - me driving people mad with my long-winded posts. So maybe good thing I didn't post for a while.

[Topcat]

Re: Recommendation for Pentium II PSU

Oh, I'm still here. (and saw a few of the threads with the builds.)
Just visiting family across the pond (in Europe) for a good while now, so haven't been as active on BCN. Since I don't really have a comfortable desk, I've been hesitant to spend more than 20 minutes on the computer in one sitting (hence not enough time to type a reply.) Plus, the keyboard on this laptop isn't great for typing a lot, either. The above post was an exception the other day, as I couldn't go to sleep that night, so typing a post on BCN was the best remedy.
Gonna be back to normal in about a week or two, though.

I figured it was something like that.....I was starting to wonder if we made you mad or something though!!

[momaka]

Re: Recommendation for Pentium II PSU

I was wondering where you've been.... you've slept through some builds!

Oh, I'm still here. (and saw a few of the threads with the builds.)
Just visiting family across the pond (in Europe) for a good while now, so haven't been as active on BCN. Since I don't really have a comfortable desk, I've been hesitant to spend more than 20 minutes on the computer in one sitting (hence not enough time to type a reply.) Plus, the keyboard on this laptop isn't great for typing a lot, either. The above post was an exception the other day, as I couldn't go to sleep that night, so typing a post on BCN was the best remedy.
Gonna be back to normal in about a week or two, though.

PIII Coppermine is similar.

Coppermine CPUs are actually very light on power use - around 40W tops for the highest models.

It wouldn't surprise me if socket 462 Athlons require more current, especially Bartons on Asus' socket 462 motherboards. Possibly later Thoroughbreds as well.
It's possible that a stock Athlon XP 2000+ doesn't use much. But I suspect the 2400+s do.

They do. Both the Pentium 4 and all of the Athlon (T-bird) and Athlon XP upped the power requirements compared to P3 and slot Athlon.

The fastest Athlon (1400) is rated for 72W max power dissipation.
Thoroughbreds actually use less power, and the fastest T-bred Athlon XP (2600+) is rated for 68.3W max.
Then it goes back up a bit with the Barton cores, with the fastest (3200+ 400 MHz FSB) needing 77W max.

Nothing seemed to stretch the older PSU designs like the socket 462 Athlons did.

Dual socket 462 motherboards were obviously the best when it comes to that.

Though, it should be noted here that a few cheap ECS motherboards for socket 478 did also use 5V rail for the CPU VRM (these used the same 2-phase DBL494 single-ended buck regulator design as the ECS K7S5A.) Luckily, these ECS boards didn't support anything newer than single-core Northwoods with 533 MHz FSB. So the top-end CPU for those was the 400 MHz or 533 MHz FSB P4 running at 2.66 GHz or 2.8 GHz and having a max power draw of about 80-ish Watts. That's still quite high, of course - around 16 Amps under max load (the same as that of a high-end dual Pentium 3 CPU setup, lol!)

[Topcat]

Re: Recommendation for Pentium II PSU

Depends on the system you're building.

I was wondering where you've been.... you've slept through some builds!

[RJARRRPCGP]

Re: Recommendation for Pentium II PSU

Also socket 462 likely requires a beefier +5V rail, especially T-birds and all socket 462 Athlons on Asus' socket 462 motherboards. PIII Coppermine is similar.

Of course, the T-bird 1.4s require more.

It wouldn't surprise me if socket 462 Athlons require more current, especially Bartons on Asus' socket 462 motherboards. Possibly later Thoroughbreds as well.
It's possible that a stock Athlon XP 2000+ doesn't use much. But I suspect the 2400+s do.

They sure make PII seem like nothing. It didn't help that I was using a Deer PSU for a T-bird! Despite it strangely not being flaky like the Soyo SY-5EMA/+ and K6-2 450 Mhz combo was.
Wouldn't the K6-2 use less current? My K6-2 combo was flaky, just because the room was warm, FFS. It acted like I had a hefty overclock, even when not overclocking! Random Windows errors. My T-bird system, ironically, wasn't like that!

Nothing seemed to stretch the older PSU designs like the socket 462 Athlons did.

[ratdude747]

Re: Recommendation for Pentium II PSU

To the OP: I'm pretty sure I have a some delta/hipro 250W PSUs that are 5V heavy I could part with. I do know I have a 300W delta out of a PIII compaq presario that's an absolute beast. I know I had a bunch of Hipro's out of dell and HP systems at one point. I also have a dell PSU from the PIII era (where they used a different pinout) that had been converted to ATX... but I don't know how many watts it is (225???)

I'll look and see (I think most of mine are at my Parent's house still)... If I find one that strikes your fancy, it's yours for the cost of shipping.

[momaka]

Re: Recommendation for Pentium II PSU

I was browsing around the net and found this.

Worth buying?

I did a bit of searching on that one and... it's a nicely built PSU, thought it may still require a recap, as evidenced by these two Russian electronics repair websites:
https://gallery.ykt.ru/photo/view/137924
http://electron55.ru/power-supply/6-...sonic-ss-300fs

At $40 and still possibly needing a recap, I'd probably pass on that Seasonic. For half the price, maybe.

I will be using a dual slot PII build and possibly messing around with some old ISA cards.

Gotcha.

If you do end up using ISA cards, you would probably want a PSU with -5V rail then.

Regarding the dual Pentium II system - power consumption on the 5V rail still shouldn't be anything too crazy, though certainly something not to task with a gutless PSU, of course.

The most power-hungry PII CPU you can get is the PII @ 300 MHz with Klamath core, which is rated for nearly 50 Watts max power consumption. So two of these would yield close to 100W of power draw from the 5V rail, which translates to 20 Amps needed. On the other hand, if you do go with a Pentium II with the Deschutes core, the max rated power draw for the fastest model (450 MHz) is about 40 Watts. Thus, you're looking at 80 Watts of power from the 5V rail for two CPUs... or about 16 Amps.

In both of these cases, a PSU rated for 22-25 Amps on the 5V rail should do the job if it is built well (like the HiPro, Delta, and LiteON linked above)... unless you plan on adding something like a Radeon 9700 or 9800 video card to the system (either of these consumes about 40-50 Watts combined from the 5V and 3.3V)

Delta are the experts in making orherwise average capacitors last damn near forever, so my vote goes to them.

On their older ones, anyways. With their newer units starting past around 2007, I see a lot more with failed CapXon and Ltec. I think that's more to do with CapXon and Ltec's quality (or lack thereof, though) over time.

Another option are old Sparkle/SPI/Fortron units. Something like this FSP250-60ATV are fairly common too. Of course, those too would likely need a recap, and I find FSP PSUs to be a bit more time-consuming to work on compared to Delta and HiPro.

I dug up the spec sheets for both the Delta DPS-300KB-1 and SeaSonic SS-300FS. They seem very similar to each other. I guess the question comes down to which one is built better?

They're both built very well. I'd probably root for the Delta, though, due to having worked with more of them. All in all, they are pretty recap-friendly.

By the way, while browsing eBay again, I found the following PSUs:
HiPro HP-235ATXAK
^ I think that one is same or very similar to this HiPro HP-235NLXAK. It's an older HiPro design with a -5V rail. I haven't recapped the above unit yet, but I still think the newer models like the HP-2507F3P and HP-P2037F3 are easier to work on. Speaking of which, there's these two for sale as well:
https://www.ebay.com/itm/132488305715
https://www.ebay.com/itm/154358155368

The LiteON / Dell PS-5251-2DS is also fairly easy to recap / work on:
https://www.ebay.com/itm/294182629435
https://www.ebay.com/itm/203578402042

[Th3_uN1Qu3]

Re: Recommendation for Pentium II PSU

Delta are the experts in making orherwise average capacitors last damn near forever, so my vote goes to them.

[teknical]

Re: Recommendation for Pentium II PSU

I dug up the spec sheets for both the Delta DPS-300KB-1 and SeaSonic SS-300FS. They seem very similar to each other. I guess the question comes down to which one is built better?

[Th3_uN1Qu3]

Re: Recommendation for Pentium II PSU

My hipro is 400W so they made em bigger than 250W too. I probably have at least one more identical functioning board which just requires fitting in a casing and plugging in the fan, but I've no idea where I put them. If you will be running a dual processor system you will definitely need a whole lot of 5V and 3.3V amps, I know that all so well.

The Seasonic is still a good option if you can get it a little cheaper.

[teknical]

Re: Recommendation for Pentium II PSU

I will be using a dual slot PII build and possibly messing around with some old ISA cards.

Would you recommending not pursuing the Seasonic at all, then?

[momaka]

Re: Recommendation for Pentium II PSU

I am putting together a Pentium II build and was wondering what would be a good power supply unit for it? Should I get an era correct one and recap it or buy a modern era one?

Depends on the system you're building.

Planning to use any ISA sounds cards (or ISA cards in general)?
- If YES, you'll probably want an older unit close to that era that has both -12V and -5V rails.

Is the motherboard a dual slot PII/PIII one? If YES, the power requirements on the 5V rail might get a bit higher and require an older PSU with a stronger 5V rail.

If the answer to both of the above is NO, then a modern PSU could probably do the job. A single-CPU Pentium II/III PC isn't very power-hungry - you'll be looking at around 50 Watts max power draw for CPU and RAM... so no more than 10 Amps on the 5V rail, which any modern PSU should be able to handle just fine.

On the other hand, if you're willing to put some time and effort to build a more period-specific system, going with an old PSU and recapping it could be a fun project that should yield a very solid and reliable PSU.

My personal favorite for an old system are old Astec power supplies, as they're pretty much guaranteed to come with high-quality Japanese capacitors inside and also extremely reliable. Of course, old Lite-On and some Delta PSUs from the PII/P3 era were also built with Japanese capacitors. But to find such PSUs, you might just have to wait a while. They aren't super rare or anything, but just not too common either anymore, as most have been recycled/thrown away by now. Every once in a while, though, they do show up for sale online, like this one 200W unit:
https://www.ebay.com/itm/19426184725...item2d3ae88cd2
Just note that while the above PSU is ATX form factor, it does have a funky 92 mm fan on the side/bottom, which may get in your way. I have a similar Astec PSU in a Gateway Select 650 and 750 PCs, and they're both 100% Japanese cap PSUs inside and built very well.

That said, I have a few other PSU favorites for older systems. The first one is the HiPro HP-2507F3P
It's only a 250W PSU with a 5V rail rated for 22 Amps, and also lacks a -5V rail. However, its 5V rail is rock-solid and can be loaded heavily without sagging at all. The 3.3V on most of the HiPro PSUs from that era are also linearly-regulated, so the 3.3V rail ripple and noise is extremely low - which is good, because SDRAM is often powered directly from the 3.3V rail on older motherboards.
Here are some active eBay listing for one in the USA:
https://www.ebay.com/itm/27464453825...item3ff217138b
https://www.ebay.com/itm/13367682047...item1f1fc267fe
In terms of recapping the above PSU... it should be pretty easy to do, as most cap spots inside are for 12.5 mm diameter caps. So finding replacements would be easy. Also, depending on what caps were installed from the factory, some of these PSUs can still be used with the original caps for a good while. I still rock a few of these PSUs in various old Pentium 4 and Athlon XP systems.

Up next, another solid PSU for older PCs is the Bestec ATX-250-12Z, ATX-300-12Z, and ATX-300-12E. All of these are built quite well and very easy to find for under $15 shipped to your door. Problem is, at this age, they usually need a recap. And more annoyingly, some of them also come with the brown glue that becomes conductive over time, so that needs to be removed as well - nothing too complicated, but certainly an extra annoyance. Also, while taking about Bestec PSUs, *AVOID* the ATX-250-12E model - that one has a killer 5VSB circuit that requires a bit more work to make it safer.

Another acceptable semi-modern alternative is the ThermalTake TR2-430W a.k.a. ThermalTake XP550-NP. Under the skin, it's identical to the HEC Orion HP585D, but the ThermalTake ones have the input filtering populated, whereas the HEC Orion doesn't.

Delta/Newton also have various old PSU models that are well-fit for retro 5V-heavy PCs. One example of that would be the DPS-300KB-1, though certainly many others are suitable too. Lite-ON also has a few models as well. In fact, here is one that came with an HP P3 PC:
https://www.badcaps.net/forum/showpo...postcount=2582

And finally, some Deer/Allied/Solytech PSUs could also be worth a recap for a PII/PIII PC if they are build decently, like this one:
https://www.badcaps.net/forum/showpo...&postcount=490
In my case, I've had the above PSU rocking in a Pentium III PC for about 10 years now (though only every other summer or so, due to the location of that PC.) Just partially recapped the 3.3V rail on it this summer (not because it had a problem, but because I found a good Rubycon cap in my hands.)

[teknical]

Re: Recommendation for Pentium II PSU

I can see if the seller will be willing to go lower on the price of the Seasonic.

I do not think I would feel comfortable recapping it with my very limited skills. If that be the case, I would rather pay someone to do it.

[Th3_uN1Qu3]

Re: Recommendation for Pentium II PSU

I think it's from the age before they used cheap caps, I remember my SS-500HT being full of Japanese caps.

[Topcat]

Re: Recommendation for Pentium II PSU

That's a nice unit but no way worth 40 bucks. Your local thrift shop or goodwill is probably a better place to look.

..and on top of that it will likely need to be recapped. New in box, I'd say $30~$40 would be fair....but it'll still need recapping, probably full of crapxons or teapos.

[eccerr0r]

Re: Recommendation for Pentium II PSU

Watch out, seen thrift shops sell bad PSUs, not sure how or if they test them...
Incidentally I saw GW selling a used 250W PSU for $20... that a deal? IMHO no...