Power supply build quality pictorial. part 2

[goontron]

Re: Power supply build quality pictorial. part 2

Here's a surprising one. Modem PSU, 10v, one and a half amps. Its a bodge-job replacement for a real POS. https://www.badcaps.net/forum/showpo...postcount=1326

Case shot.

Not inspiring....

Board topside.

This is promising! Good insulation, no Brown Gorilla Snot, plenty of filtering. Looks like the board has provisions for another rail. Actual safety rated caps.

Topside-BottomWise!

No bad solder. Plenty of isolation. Not bad.

And the Money-Shot!

Decent Chemi-Con caps.
Secondary Filter: 1000uF, 16v.
BootStrap: 47uF, 50v.
Primary Filter: ? It was wrapped in yellow tape... Very large though.

Goontrons rating: B for beautiful. Needs more heat sink, and the primary cap is resting on some large resistors. More than satisfactory for its intended use. Looks Delta OEM.

[Behemot]

Re: Power supply build quality pictorial. part 2

I'd guesstimate that primary cap around 47 uF/400 V.

[momaka]

Re: Power supply build quality pictorial. part 2

Here's a surprising one. Modem PSU, 10v, one and a half amps.
...
Goontrons rating: B for beautiful. Needs more heat sink, and the primary cap is resting on some large resistors.

For a 1.5A adapter, the heatsinks look plentiful.

With those caps, I would have argued you give it an "A"... but it looks like it is a 2-transistor design. So in that case, "B" seems appropriate, as 2-transistor designs are not very efficient. The small cap on the primary may also be a "critical" cap... but again, I see nothing but good caps in this adapter, so that shouldn't be a problem.

A world of a difference compared to the gutless adapter you posted in the other thread.

[kaboom]

Re: Power supply build quality pictorial. part 2

Decent Chemi-Con caps.
Secondary Filter: 1000uF, 16v.
BootStrap: 47uF, 50v.
Primary Filter: ? It was wrapped in yellow tape... Very large though.

33-47u, 400V? Maybe 68u/400V.

Actually, since it's rated only up to 120V AC, the cap could be an 82u/200V unit.

Goontrons rating: B for beautiful. Needs more heat sink, and the primary cap is resting on some large resistors. More than satisfactory for its intended use. Looks Delta OEM.

Agree! Looks rather non-RoHS-ey for 2011.

[goontron]

Re: Power supply build quality pictorial. part 2

^ That was my thought. 82uF/200v.

I gave it a nice dose of 60/40 before i welded the case back together.

[RukyCon]

Re: Power supply build quality pictorial. part 2

Here we are with an ebay 12V 2A power supply.
Label.

Not looking promising.
Top side.

Not bad IMO. I think they did a good job with it.
Has a nice Y-class capacitor and a PI coil on the output side. I'd take some points off for the cheap glue. The input capacitor is not original to this power supply and no, i did not replace it.
The big transistor is a STD13005 and the smaller looking one is a AZ431.
And bonus points to whoever noticed that the input capacitor is bulging.
Bottom side.

Looks like they did a decent job on isolation from the input.
The hot glue was added by me to stop one of the solder pads from being ripped up from the PCB.
Solder seems to be good.
Cap shot.

Input: 10uf 400v
Bootstap: 220uf 16v
Output: 680uf 16v
Brands: BERYL, Ltec.

Overall i'd say this thing is not bad for the price.

[eccerr0r]

Re: Power supply build quality pictorial. part 2

Vaguely familiar to the 2-transistor 5VSB circuitry modified to 12V, compacted into a wall wart?

[RukyCon]

Re: Power supply build quality pictorial. part 2

The power supply is OEMed by unifive. Some of there products seem to be UL listed when looking on there website.

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

Here we are with an ebay 12V 2A power supply.
Label.

Not looking promising.
Top side.
...
Overall i'd say this thing is not bad for the price.

IC1 is an optocoupler, and IC2 is in a TO-92 package. I'm guessing IC2 is a TL431 (or clone), and the output is regulated. The MJE13005 clone transistor - bipolar, not a MOSFET - should be plenty beefy for 24W. As long as its heatsink and the traces "heatsinking" the output rectifier are adequate, it looks reasonably solid.

[RukyCon]

Re: Power supply build quality pictorial. part 2

...I'm guessing IC2 is a TL431 (or clone)...

IC2 is a AZ431.

[RukyCon]

Re: Power supply build quality pictorial. part 2

I may all a new wires to the output because the ones that are there are thin and are soldered across the output capacitor making the PI coil useless unlike the old wires.

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

IC2 is a AZ431.

That self-oscillating discontinuous flyback circuit using a bipolar transistor as the switch and a **431 as an error amplifier has been around for nearly 40 years. It's not super high efficiency, but the low component count generally, and the lack of a large separate output inductor make it an attractive choice for small adapters.

[RukyCon]

Re: Power supply build quality pictorial. part 2

That self-oscillating discontinuous flyback circuit using a bipolar transistor as the switch and a **431 as an error amplifier has been around for nearly 40 years.

Interesting that the design has been around for that long.

It's not super high efficiency, but the low component count generally, and the lack of a large separate output inductor make it an attractive choice for small adapters.

When it comes down to adapters, i don't really care too much about the efficiency. [Unless it draws many times more power than it outputs.]

And IIRC the output inductor is usually referred to as a 'PI coil'.

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

Interesting that the design has been around for that long.
...
And IIRC the output inductor is usually referred to as a 'PI coil'.

Here's a second generation single output example from Boschert, dated 1983:



Here's a first generation multiple output example from Boschert, dated 1982:



The latter was in production when I started at Boschert in 1980.

Those little inductors on the outputs are there primarily to reduce spike and ringing noise, not to filter switch frequency ripple.

Boschert's second generation discontinuous flybacks were part of a fairly large scale effort to get the pricing for their low and medium power products under $1 per watt. I don't think the first-gen OL25 was replaced, but I know second-gen XL standard products ranged from that 30W single output to a model that could do 165W convection cooled or 185W with forced air cooling. The guy who did all those designs - one guy! - was a genius.

By way of contrast in terms of pricing, in 2000 Delta Products was charging Compaq, Dell, and Apple $13-$16 for 200W-250W power supplies.

[RukyCon]

Re: Power supply build quality pictorial. part 2

I wanted to see how the newer 12V 2A power supply's on ebay looked and all of the newer ones are crap, Oh well.

I may make a post about the newer crappy ones if anyone's interested.

[kevin!]

Re: Power supply build quality pictorial. part 2

I found this source on a Pentium 3 that I found at a recycling point.
The source seems very decent, except for the primary capacitors that are garbage, which are SC, but the secondary ones are Nicon, for me Nicon is good brand, I have seen sources with Nicon with 40.000hy and they were in very good condition, although if it does missing the change too.
The rest of the source, I think it's 500W, weighs a lot, and the PFC has a real winding inside, it's not the typical one that put fake PFCs.
I do not have data of the switch, nor the transistor, it is very complicated access, and I do not want to break, because I will use it, I will change the 2 primary capacitors.
What opinates, is it good? I see her quite well.

[momaka]

Re: Power supply build quality pictorial. part 2

I have my doubts that PSU will do 500 Watts. Maybe around 400-450 Watts at most. As well-built as it looks, there are still several things I don't like about it:

1. The output filter caps seem way too small. This PSUs appears old and probably has a low switching frequency. So if anything, those output caps need to be much bigger to properly filter 500 Watts worth of power.
2. No combined power rating for the 12V rail or the 3.3V and 5V rails is dodgy.
3. Main transformer is labeled ERL35. To me it looks like it's close to size 39, but maybe the picture is deceiving. In any case, even with an ERL39, you won't be able to do 500 Watts - not with a slow-switching half-bridge topology. Which leads me to my next point.
4. This PSU uses half-bridge topology, most likely with two BJTs on the primary. Such an ancient topology is not very efficient - you'd be lucky if it peaks close to 80%. Most are less than 75%. So with that kind of [in]efficiency, 500 Watts wouldn't really be possible with that primary heatsink.

All that said, this still appears to be a very decent PSU. With good brand caps, it should last a very long time, especially since it has a very simple design with passive PFC. Thus, I definitely suggest recapping it and keeping it.

It may not do too well in a very 12V-hungry modern PC, but it should be okay for a mid-range PC. And because it has a strong 5V rail, it would also be suitable for running an old 5V-hungry rig, like a top-of-the-line Athlon XP PC with a 5V-heavy GPU (Radeon 9700/9800).

[Behemot]

Re: Power supply build quality pictorial. part 2

Xilence units are usually half-decent, not sure about this old series but they usually deliver the power. Though at least the older ones were using all those "peak power" crap tricks, just check my review of the R6: https://www.hardwareinsights.com/xil...p400r6-review/

[kevin!]

Re: Power supply build quality pictorial. part 2

I have my doubts that PSU will do 500 Watts. Maybe around 400-450 Watts at most. As well-built as it looks, there are still several things I don't like about it:

1. The output filter caps seem way too small. This PSUs appears old and probably has a low switching frequency. So if anything, those output caps need to be much bigger to properly filter 500 Watts worth of power.
2. No combined power rating for the 12V rail or the 3.3V and 5V rails is dodgy.
3. Main transformer is labeled ERL35. To me it looks like it's close to size 39, but maybe the picture is deceiving. In any case, even with an ERL39, you won't be able to do 500 Watts - not with a slow-switching half-bridge topology. Which leads me to my next point.
4. This PSU uses half-bridge topology, most likely with two BJTs on the primary. Such an ancient topology is not very efficient - you'd be lucky if it peaks close to 80%. Most are less than 75%. So with that kind of [in]efficiency, 500 Watts wouldn't really be possible with that primary heatsink.

All that said, this still appears to be a very decent PSU. With good brand caps, it should last a very long time, especially since it has a very simple design with passive PFC. Thus, I definitely suggest recapping it and keeping it. If it does not reach 500W, nothing happens.


It may not do too well in a very 12V-hungry modern PC, but it should be okay for a mid-range PC. And because it has a strong 5V rail, it would also be suitable for running an old 5V-hungry rig, like a top-of-the-line Athlon XP PC with a 5V-heavy GPU (Radeon 9700/9800).

Thank you very much ,
I think the same, the capacitors look very small, in addition being SC will not have half of its capacity of what it marks on its label.
Well, I'm not going to ask too much, I'll have it for a gtx8800 with a core 2 duo.
I have been looking for information about the manufacturer of this source, and it is the same one that manufactures for NOX. (Huizhou Xin Hui Yuan Tech)
Nothing happens if it does not reach 75% efficiency, at least if it works, and has good protection, I have enough.

Xilence units are usually half-decent, not sure about this old series but they usually deliver the power. Though at least the older ones were using all those "peak power" crap tricks, just check my review of the R6: https://www.hardwareinsights.com/xil...p400r6-review/

You see, I've seen them in many sources putting peak for 30 seconds for example.
My PSU I think will be the same.

I will recap the primary capacitors and give them a second life.
Thanks

[Stefan Payne]

Re: Power supply build quality pictorial. part 2

That's a Pre Listan era Xilence. Maybe they were too good and that's the reason Xilence went under (and was boght by Listan).

Though there are way way worse...

I'd treat that like a 250-300W unit with max 20A on +5V/3,3V and 15-18A on +12V combined.