Power supply build quality pictorial. part 2

[goodpsusearch]

Re: Power supply build quality pictorial. part 2

I found a couple of old Fuhjyyu's in some device that predates the old Antec Smartpower Fuhjyyu plague and they actually are still okay... Not sure if's just that one period with the scandal that they produced so many poppers...

The reason those caps failed a lot in Antec psus has to do with how hot they got due to the design of the parts location inside and also the fact that the fan controller was configured very aggressively to be silent. And the fact that their efficiency was nowhere close to what we have today didn't help either (~74%)

[pdavid]

Re: Power supply build quality pictorial. part 2

My question is why is it using an overspecced and odd 7905 negative rail regulator when a cheaper 78L05 or 78M05 would do?

Sorry, 7905 was a typo. It is a L7805C positive voltage regulator. It is visable on the pictures. The ic has that simple piece of metal screwed on for heatsinking. The pcb silkscreening suggests a TO-92 device instead of TO220 that is crammed in there.

[eccerr0r]

Re: Power supply build quality pictorial. part 2

Earliest ATX 1.0 spec indeed only specced only 100mA so I suspect they may have built to spec though whether or not they exceeded or not is another question. My question is why is it using an overspecced and odd 7905 negative rail regulator when a cheaper 78L05 or 78M05 would do? Incidentally I'd not call this "cheap" but rather "old, inefficient" ... those transformers are not cheap to source or ship in volume...

I found a couple of old Fuhjyyu's in some device that predates the old Antec Smartpower Fuhjyyu plague and they actually are still okay... Not sure if's just that one period with the scandal that they produced so many poppers...

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

There is a seperate transformer attached to the casing that looked like passive PFC at first but it isn't. The 5V standby has 100mA current capability and it is generated using this trafo, rectifier and a 7905 regulator. I haven't seen this "cheap" method before.

The current rating for the +5SB is just .1A, some the effect on efficiency is minimal. A 50/60 Hz transformer, recifiers, and 7805 3T regulator might have been cheaper than a flyback switching regulator circuit. .1A was pretty minimal for that era. I would expect 1.0-1.5A.

A TL494 clone and MJE13007 clone BJTs would easily have been adequate for the ATX spec of that era and the 235W rating; the heatsinks were OK, if not spectacular heavy metal. Looks like the PCB was laid out to allow higher power switch transistors and output transformer. The 330uF input caps might have been marginal for hold-up time. The fluctuating output voltages and high ripple could be due to the 24 year old output caps having increased in impedance. Replacing the F-yus with Nichicon PJ or PW or NCC LXV or LXZ series caps (which were in common use in the late 1990s) might result in better performance.

[Agent24]

Re: Power supply build quality pictorial. part 2

What a fascinating design! I want one just for the sheer novelty.

[pdavid]

Re: Power supply build quality pictorial. part 2

A saved an old ATX power supply from recycling last week.
The casing is damaged, has dents, a broken fan but the insides are intact.

EverPower brand with a 235W Channel Well Tech guts from 1997.


There is a seperate transformer attached to the casing that looked like passive PFC at first but it isn't. The 5V standby has 100mA current capability and it is generated using this trafo, rectifier and a 7905 regulator. I haven't seen this "cheap" method before.
The standby trafo has primary winding taped for both 110V and 230V.


The unit has ok EMI filtering, 4 Amp bridge rectifier, 330uF Matsushita input capacitors.
It's a half bridge topology with two 13007 BJTs controlled by KA7500 pwm.



A 339 comparator is used to supervise the output voltages. There is also a seperate fan controller circuit.

https://www.badcaps.net/forum/attach...5&d=1637581493


The 3.3V rail is also unusual. No mag amp circuit.
A UTC34063 is set up in step down configuration to make the 3.3V work.


Secondary electrolitic capacitors are all Fuhjyuus so that's bad.


I've cleaned and tested the psu. Turns on, voltages are a bit low-ish and fluctuating, ripple is probaly high also. Kind of unusual early ATX unit.

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

CapXon is a brand not respected here. However it looks like some of the output capacitors are polymer types.

The power supply puzzles me. It is rated as simple "80 Plus", but those heatsinks look insufficient for a 600W power supply. The main transformer also looks odd. My best guess is that the switch frequency is somewhat high, and phase modulation is used rather than pulse width modulation. But if that's the case, I would think it would be rated as at least "Bronze" or "Silver".

[Togepi]

Re: Power supply build quality pictorial. part 2

Hello,

here I have a Cooler Master power supply MasterLite 600Watt. It is new and unused. All capacitors in the device appear to be from CapXon. I don't know if this is good or bad now. The device is new and unused. I would have been interested in who the right manufacturer of the power supply is. Can someone see that from the pictures?





Regards

[Behemot]

Re: Power supply build quality pictorial. part 2

Looks really well-built, overall. Cooler Master isn't exactly know for picking the best OEM's for their PSUs (but far from the worst, too)... though I think that applies more for their lower-end units. But this one, whoever the OEM behind it is... I like what I'm seeing.

V series is quite nice, I've reviewed different models yeaaaars ago on HWI, looks like you haven't read Last was V650 https://www.hardwareinsights.com/coo...odular-review/ looks I have the V850 still opened and not finished for like 3 years now, shame on me

[terradrone]

Re: Power supply build quality pictorial. part 2

Do you still own this power supply? I have one that is not working; has a blown IC. I was hoping you could help me identify this chip because mine is so badly damaged that the partnumber isnt visible anymore.

Nevermind, i found out the partnumbers that i needed. For future reference: This is about a Dell PSU from an Alienware Aurora R4, model N875EF-00 / pcb is Newton NPS-875BP. The parts that i needed to identify where c903 and ic903. C903 seems to be a 100nf 630v 10% film capacitor. IC903 is a TNY280PN. This psu also seems to be used in the Dell Precision T5500 workstation.

[terradrone]

Re: Power supply build quality pictorial. part 2

Here show you a PSU Dell alienware aurora r3, specifically a Newton Power/Delta electronics n875ef-00
The source carries an ADDA fan.
I am surprised by its design, it has hardly any transformer, does anyone know how this type of PSU works? It amazes me how it is built, I have never seen anything to it.
There are LTEC capacitors, but they have 30,000h, they have not given problems, but surely change the capacitors for quality ones.

Do you still own this power supply? I have one that is not working; has a blown IC. I was hoping you could help me identify this chip because mine is so badly damaged that the partnumber isnt visible anymore.

[TechGeek]

Re: Power supply build quality pictorial. part 2

I give it between a month and 6 months since you let it know you're willing to spend time on it.

[momaka]

Delta Electronics DPS-300ab-15b REV:01F [PCB: DPS-300ap-15b] - recap & mods

After decommissioning the above DPS-300ab-15b PSU from the Gateway PC that it was in, I put it on the shelf with the intention to recap it. I already knew it had a 2-transistor 5VSB design (with a “critical” cap too), so a recap was undoubtedly going to be required at some point in time. In 2018, however, I ran short on working PSUs while putting together some spare PC builds. So I installed this PSU (still with the original caps) as a “temporary” thing in a HP PC with an Athlon II X2 that I didn’t care much about (due to having some issues with the motherboard.) To say that I didn’t use this PC afterwards would be an understatement. I connected it to power maybe only twice in 2 years. Then, last fall as I was fixing up another similar PC and needed to power up the Athlon II X2 system to try some tests on it with the hardware from the other system, I of course ran into issues with this unrecapped Delta PSU. Basically, as soon as I applied power, I heard a very high-pitched squealing, whining noise. I powered off the PC, but the noise continued. At that point I was almost certain what the issue was – bad caps on the 5VSB, likely. So I unplugged the PSU almost immediately. And I was right about the problem!



After so many years, I suppose those CapXon GL caps beat the Ltec to the finish line (of FAIL.) I swapped out the bulging CapXon GL, 16V, 1500 uF with a Nichicon HN, 16V, 1500 uF that I had on hand. This fixed the 5VSB squealing on the spot. Of course, I put the PSU aside again, so that this time I could finish the recap (as I had planned when I originally decommissioned the PSU.) Besides, the Ltec caps were also starting to show suspiciously increased capacitance, IIRC. So eventually I did the recap and this was the result:





To understand what is going on, here is a cap diagram of the output capacitors:



As you can see, I still didn’t do a 100% full recap (left the 2nd 5VSB cap and 2nd 12V rail caps with the original Taicon ones, as Taicon doesn’t seem to fail very often in Delta PSUs.) The 1st -12V rail filter cap was replaced with a recycled Taicon (from another Delta??) The 12V rail also received an “interesting” treatment: the Ltec LZG 680 uF cap was replaced with a Rubycon ZL 1200 uF cap and the CapXon GL 1500 uF cap was replaced with an Ltec LZP 2200 uF cap. Both of these were recycled parts (the Ltec I think I pulled from the 12V rail on one of the HiPro 300W units a few pages back.) But apart from these, the rest of the PSU received good caps. The 3.3V rail received 2x new Rubycon ZLH 6.3V, 2200 uF. The 5V received 1x Panasonic FC 16V, 2200 uF, 12.5 mm cap (recycled part from Vcore on a Foxconn motherboard, so best not used on higher voltages) and also a new Rubycon YXJ 10V, 2200 uF part. As for the “critical” cap on the 5VSB circuit, I don’t actually remember what I used as a replacement there or if I replaced it at all. It was a Taicon PW and measured good ESR and capacitance. So I might have left it for when I get more 25V, 100 uF caps, as I don’t have any ATM.

After giving the PSU a recap, there was still one thing I wasn’t too keen about – the discoloration / PCB darkening around diode D951 on the primary side next to the 5VSB transformer. This darkening has been there ever since I took the pictures of this PSU back in 2014. In this case, D951 is the rectifying diode for the primary side auxiliary rail, which provides power to both the 5VSB feedback circuitry on the primary side and also power to the PWM controller on the primary. Like with the DPS-300KP PSU I showed, this diode is just a standard 1N4002 (not 1N4001 as I noted in the 300KP post – that’s a mistake.) I’m not sure why Delta insists on using a regular diode here (not even fast-recovery type!), though when I tried changing it in the Delta 300KP PSU, the 5VSB lost regulation and started oscillating wildly. Of course, I wanted to see if the Delta DPS-300ab-15b would do the same thing, so I tried it again – I replaced diode D951 (originally 1N4002) with an FR153 diode. What’s interesting is that the 300ab-15b did not have any problems with this change and the 5VSB circuit continued to work normally. However, even my new diode there was still running a bit too hot (though not as much as before.) Therefore, I removed it again, soldered a piece of used copper braid to the Cathode lead, and then soldered it back in the circuit. You can actually see that modification in the first recap picture I posted above (on the left side.) After doing this, the diode seemed to run a bit cooler as the copper braid was doing its job of sinking heat away from it.

And speaking of the 5VSB circuit, I drew the schematic of that so I could get a better idea of what’s going on. Here it is:



One interesting note for the DPS-300ab-15b 5VSB circuit is that it looks very similar on the primary side (despite me arranging the components on the schematic in a slightly different order) to that of the HEC Orion HP585D PSU I posted a while back. That said, both of these 5VSB circuits are quite power-hungry and easily waste 3-4 Watts without a load. (Well, that hot diode in the 300ab-15b has to take its power from somewhere. )

Finally, I replaced the STTH1602ct fast recovery rectifier on the 12V rail with an MBR20100CT that came from the KDMPower MIPC MI-X8775CD PSU that I repaired not too long ago. That PSU can’t really provide much power anyways, so it was a bit of waste to have 2x 20 Amp Schottky rectifiers on its 12V rail, while the Delta DPS-300ab-15b was just chugging barely along with a single 16 Amp FR rectifier. You can see the “new” 12V rectifier in the Delta PSU in the 2nd recap picture above. This did actually improve the 12V rail cross-load regulation by about 0.2 to 0.3V and brought it much closer to 12V under load. So I think that was a good change.

And that’s all I really have for this Delta PSU. Now cast your votes when you think I will have to open it again to change that 2200 uF Ltec LZP cap on the 12V rail.

[momaka]

Delta Electronics DPS-300ab-15b REV:01F [PCB: DPS-300ap-15b]

Don't ask how many Delta PSUs I have – probably too many. This one, model DPS-300ab-15b, I didn't actually obtain as a standalone find or “purchase”. Rather, it was the PSU that came included inside a dumpster-picked Gateway GT-5656 desktop I found back around 2014 or so (and I believe was the original PSU for that PC too.) So let's have a look and see if that looks any different.





The case on this one indeed looks a little different from the other Delta units that I posted. Not only that, but the output wiring also seems to better match the components in the system: that is, besides the usual 20-pin ATX connector and 4-pin 12V CPU power connector, there are also 2x SATA, 2x or 3x Molex drive, and 1x floppy. The GT-5656 PC doesn't have a floppy drive, but the floppy connector is used for a special Gateway external drive bay. And the Molex drive connectors are for the optical drive(s), which are oldschool IDE in that system, whereas the HDD(s) are SATA. Only thing I'm not sure about is why Gateway had it with a 20-pin ATX connector, as the motherboard in there (ECS MCP61PM-AM) has a 24-pin ATX connector. But I suspect perhaps Gateway just went with whatever was the cheapest, as the output cables of this Delta PSU consist mainly of 20 AWG wires… and they aren't very long either. So the PSU feels a bit like a “cheapie”. The label seemed fairly modest, though, with only 15 Amps on the 12V rail.



Note that there are no OEM names or internal model numbers here. Rather, the label states that it's a plain-straight Delta PSU. So perhaps Gateway just used a standard off-the-shelf unit? Either way, let's see what's inside it.





Well, there isn't anything much intriguing about this PSU: standard STF topology for the main PS with an oldschool 2-transistor self-oscillating 5VSB circuit. Cap choices are a mix of mostly Ltec and CapXon, with a few Taicon in there too (and Samxon for the primary filters.) The output filter toroid for the main PS 5V/12V rail isn't oversized like with some of the recently posted Delta PSUs I showed above, but should still be adequate for the task. It does use the more efficient -52 core material, after all. The only real letdown is the 12V rail's rectifier – it's a 16 Amp, 200V, fast-recovery –type rectifier. So how Delta is supposed to get 15 Amps of current out of it when the topology is single-transistor forward, I'm not quite sure about. 12-13 Amps is a more realistic number, IMO. Either way, I de-commissioned the PSU from the Gateway PC it was in, because with the stock Athlon 64 X2 6000+ CPU (89W TDP) and a Radeon HD 2400 GPU (19W TDP), the PSU was already pushing out very warm air from its exhaust when gaming on that PC. Moreover, the 12V rail was dipping a bit low at 11.6-11.7V, IIRC. So the 12V rail rectifier definitely was under some stress. However, I didn't do the decommissioning at least a year after I used the PC as-is. So all in all, the DPS-300ab-15b held up just fine. Once I swapped it out, it was sitting around mostly as a spare.

Anyways. Moving onto the solder side… there isn't anything special about the solder quality of the PCB either – it's just standard clean Delta work, as usual (which is always nice! )



And that concludes all the pictures I have of the stock PSU. No fan label shot, as I didn't normally take any back when I took these pictures (note the date of when they were taken, and thus how long I had them sit on my HDD, lol.) However, the fan in this PSU is a Delta, too – a dsb8012h to be exact, rated for 0.21 Amps at 12V.

~~~~~~~ Parts Summary ~~~~~~~~

ICs:
UC3843bn (PWM controller main PS, primary side), DWA108 (supervisor IC, secondary side), LM339an (OCP + other protections?), and 7912 voltage regulator (for -12V rail)

Wiring:
* input: 600V, 18 AWG
* output: 300V, 20 AWG
* output connectors: 20-pin ATX, 4-pin 12V CPU, 2x SATA, 3x Molex drive, 1x floppy

Primary Side:
* Input Filtering: two X2-class caps (0.47 uF and 0.22 uF), six Y2-class caps (2x on receptacle and 4x on board), two CM chokes, 1 SM choke
* Input protection: F8AH 250V fuse, no NTC thermistor (?? ), 2x MOVs across each cap
* ”GBU6J” bridge rectifier
* 2x Samxon LP, 200V, 680, 22x45 mm, 85°C caps
* 1x W9NK90z MOSFETs (TO-247) for main PS
* 3NK60zfp MOSFET (TO-220FP) and 2N2222A BJT (TO-92) for 5VSB circuit
* ERL35 main PS transformer and EEL16 (??) 5VSB transformer

Secondary Side:
*** T103(?)-52 toroid filter for 5V/12V/-12V rails
*** toroid filter for 3.3V rail (3.3V rail is mag-amp regulated) uses -26 core material

* 5VSB
*** 1x CapXon GL, 16V, 1500 uF, 10x25 mm before PI coil
*** 1x CapXon GL, 16V, 680 uF, 8x20 mm after PI coil
*** PI coil: 3 mm core, 15-turn, 22 AWG wire
*** SB340 Schottky diode for rectification

* 3.3V Rail
*** 2x Ltec LZG, 6.3V, 2200 uF, 10x24 mm with PI coil in between
*** PI coil: 3 mm core, 6.5-turn, 18 AWG wire
*** STPS2045ct (TO-220) Schottky rectifier
*** 470-Ohm (?) SMD load resistor

* 5V Rail
*** 1x Ltec LZG, 10V, 2200 uF, 10x30 mm before PI coil
*** 1x CapXon GL, 10V, 1500 uF, 10x24 mm after PI coil
*** PI coil: 3 mm core, 6.5-turn, 18 AWG wire
*** two STPS2045ct (TO-220) Schottky rectifiers in parallel
*** 150-Ohm (?) SMD load resistor

* 12V Rail
*** 1x Ltec LZG, 16V, 680 uF, 10x16 mm
*** 1x CapXon GL, 16V, 1500 uF, 10x25 mm
*** no PI coil – only a current shunt (for OCP) between the two caps
*** STTH1602ct (TO-220) fast recovery rectifier

* -12V Rail
*** 1x CapXon GL, 35V, 220 uF, 8x18 mm before 7912 linear regulator (no PI coil)
*** 1x Taicon PW, 25V, 220 uF, 8x12 mm after 7912 linear regulator

[momaka]

Re: Power supply build quality pictorial. part 2

Cooler Master V1200 (80 Plus Platinum certified)

YAY! Finally a newer PSU that doesn't have those pesky black-colored PCBs. In fact, those red PCBs look like someone stuck an oldschool ATI Radeon video card in there.

330uF 420V x2 + 390uF 420V primary filter (all Nichicon GG)

Nice! Good to see the primary input capacitance wasn't cut to some minimum spec value. 1050 uF split across 3 big 420V caps should allow the caps to hopefully not suffer as much from the high ripple current of the APFC stage (especially at low load - those caps should just be chillin' in there. )

330uF 16V x6 Nichicon FPCAP before all +12V output inductors with 1000uF 16V Chemi-Con KY after each output inductor
3900uF 16V Rubycon ZLH before +5VSB inductor and 3300uF 6.3V Chemi-Con KY after it
Small electrolytic capacaitors are Rubycon YXG (mostly) or Chemi-Con KY

Japanese caps? Yes please! Good to see those and not the 2nd tier brands.

Looks really well-built, overall. Cooler Master isn't exactly know for picking the best OEM's for their PSUs (but far from the worst, too)... though I think that applies more for their lower-end units. But this one, whoever the OEM behind it is... I like what I'm seeing.

With that said, I think the APFC will probably be the first to fail when it kills the primary caps... but that might not happen for probably at least 10 years, if not more, seeing how many of those caps there are on the primary and their ratings/specs.

[japlytic]

Re: Power supply build quality pictorial. part 2

Cooler Master V1200 (80 Plus Platinum certified)

Main board:
330uF 420V x2 + 390uF 420V primary filter (all Nichicon GG)
330uF 16V x6 Nichicon FPCAP before all +12V output inductors with 1000uF 16V Chemi-Con KY after each output inductor
3900uF 16V Rubycon ZLH before +5VSB inductor and 3300uF 6.3V Chemi-Con KY after it
Small electrolytic capacaitors are Rubycon YXG (mostly) or Chemi-Con KY
Two parallel bridge rectifiers on the primary side (cannot read type number without removing them)
6R125P x3 MOSFETs and C3D10060 SiC rectifier for the PFC stage with 5R199P x4 MOSFETs for the main converter
014N04L x8 synchronous rectifier MOSFETs for the main +12V rail

Output connector board:
All electrolytic capacitors on this board are Nichicon FPCAP
470uF 16V on the inputs of the +3.3V and +5V DC-DC converters
470uF 16V on the +12V rail (disk drive connectors)
560uF 6.3V x4 on each of the the +3.3V and +5V rails
For each of the +3.3V and +5V DC-DC converters, 4D030L x3 switching MOSFETs

[momaka]

Delta Electronics DPS-300sb A REV:03F [PCB: DPS-300sp A] – recap & tests

The 12V rail is coupled to the 5V rail too, so regulation and 12V-heavy cross-loading shouldn’t be a problem… though I will test that eventually, after I recap the PSU.

Right, so I did that - the DPS-300sb indeed performed quite well with both 5V-heavy and 12V-heavy cross-load tests. Basically I ran 4 tests, with the first 2 being more 12V-heavy and the last two more 5V-heavy.
test #1: 6 Amps on 12V rail, 2.5 Amps on 5V rail, 2 Amps on 3.3V rail
test #2: 12 Amps on 12V rail, 5 Amps on 5V rail, 2 Amps on 3.3V rail
test #3: 1.7 Amps on 12V rail, 10 Amps on 5V rail, 2 Amps on 3.3V rail
test #4: 2.22 Amps on 12V rail, 20 Amps on 5V rail, 2 Amps on 3.3V rail

For 12V-heavy tests #1 and #2, the 12V rail on the DPS-300sb dipped a bit low at 11.85V and 11.68V respectively… but that’s still well within spec. Meanwhile, the 5V rail peaked only up to about 5.10V. Now the 5V-heavy tests #3 and #4 are more interesting. In particular, some group-regulated PSUs I’ve tested so far – even older ones that should seemingly have done better with 5V-heavy loads – would pass test #3 just about OK, but a few got out-of-spec on the 12V rail voltage with test #4. On the other hand, this Delta DPS-300sb did not have such problems at all. Here are the voltages for test #4:


As you can see… yes, the 5V rail started dipping a bit low at 4.87V, but was still in spec. In fact, considering this load (20 Amps) represents 80% of the maximum the 5V rail is rated for, the results are rather good. What I like even better about this PSU is how well-controlled the 12V rail was with the 5V-heavy load test, peaking at no more than 12.21V. Most off-brand PSUs I’ve tested (an Apevia 620W, a Sirtec/Task TK-930TX, and a few others) were already getting close to out-of-spec on the 12V rail on test #3. With test #4, the 12V rail on all of them went above 12.6V. In fact, the Task TK-930TX was already barely below 12.6V on test #3 and close to 13V on test #4.

So in a few short words, the Delta DPS-300sb did very well with cross-loading, especially considering that it’s a group-regulated PSU.

Of course, all of the above tests were done after the PSU was recapped. On that note, here is a cap diagram of the PSU:


There aren’t really that many small caps or any obscure ones, so the recap was pretty straight-forward.



The bulging CapXon GL 2200 uF caps on 3.3V rail were replaced with 2x Rubycon ZLH of same voltage and capacity. ZLH has pretty low ESR (especially for older PSUs), but should be OK for the 3.3V rail here, as mag-amp circuits don’t mind them as much.

For the 5V rail, only 1 of the 2 CapXon GL caps was changed – the 1st one. I used UCC KY series rated for 10V and 2200 uF.

For the 12V rail, I did a slight upgrade with a UCC KYB rated for 16V and 2200 uF.

For the -12V rail, I didn’t change the small 100 uF output cap on the 7912 regulator, as those rarely go bad (and even then, it’s not too big of a deal, as 78xx/79xx regulators don’t need much in the way of output caps to still regulate well.) However, I did change the input to the 7912 regulator – that is, the cap for the -12V rail labeled “raw”. Here, I used UCC KZE 25V, 470 uF, as that’s the only low-ESR 25V-rated cap I had. Otherwise, I do have plenty of choices for 16V… but because this is the input to the 7912 regulator, it is advisable to use at least 25V caps, as 16V caps may not have adequate voltage overhead.

Finally, the 5VSB: I replaced the first filter cap – a CapXon GL 16V, 1500 uF - with a Nichicon HN 16V, 1500 uF. It’s unnecessary to go with this kind of ultra-low ESR cap here. I just have a lot of these in stock leftover from scrap Xbox 360 motherboards, and I haven’t found a 5VSB / flyback circuit that minds the drop (upgrade?) in ESR so far. Thus, I’ve been doing it to a number of PSUs now. I didn’t change the 2nd cap in the 5VSB output filter (a CapXon GL rated for 10V and 470 uF), but the Nichicon HN should be more than enough to handle everything by itself, even if that 2nd filter cap failed.

Apart from the output caps above, it is strongly advisable to change the small caps on the primary side as well (labeled “PWM run cap” and “5VSB startup cap”). In my case, the PWM IC run cap was already a UCC KY, if I remember correctly. But the 5VSB startup cap was a CapXon KM and ever so slightly bulging. It still read OK on capacitance (about 43 uF), but its ESR was showing about 29 Ohms, IIRC – basically way too much for a small 5x11 mm cap. Thus, I replaced it with a UCC KY of the same voltage and capacity (25V, 47 uF.) Then there is another 50V, 47 uF cap I labeled with teal color on the cap diagram above. Not sure what this is for, but I replaced it anyways. The two small caps next to the controller (that I didn’t label on the cap diagram) are rated for 1 uF and 2.2 uF. I replaced these as well, just in case. Finally, there is also a 10 uF cap close to the fan connector that I didn’t label on the cap diagram. This cap is for filtering power going to the fan and isn’t really critical in any way. Thus, I didn’t change that one.

In any case, the recap above should hold up quite well for a long time. Probably the 2nd output cap on the 5V rail may need changing at some point in time, as that is the only large CapXon left (aside from the primary caps – but those should be OK for a while longer too.) I’m not too worried about it, though, as that cap is easily visible from the front vent holes on the PSU. So when I see it going bad, I’ll change it (running short on 10V, 2200 uF UCC KY caps currently, hence the “short-cut”.) Besides, more than likely I will end up using this PSU with a basic 12V-based PC. So the 5V rail shouldn’t see too much loading. Of course, no telling if plans will change and where I will use this PSU. Currently, it’s still sitting in my spare PSU stash and only used for testing. It’s really handy to have a few of these OEM Delta and HiPro PSUs around, though.

Also, does anyone see the slight “mod” I did in the 2nd picture of the recap above?
Probably doesn’t matter too much, but I made a small heatsink for the 5VSB switching transistor. I was trying to get rid of an end angle cut in an aluminum L-bracket that I needed to cut for something else. So I figured I might as well cut it a bit longer and make something useful out of it rather than end up with useless scraps. The modded heatsink is screwed onto the transistor with thermal compound, of course. And I also have it glued to the primary heatsink and 5VSB transformer with silicon glue. I mean, this won’t be a proper momaka PSU recap without any goofy meddling in there, right?

If Delta uses the YYWW date code format the PSU is about 15 years old.

That sounds about right.
This Delta DPS-300sb came from an HP mATX tower with Windows XP stickers and what appears to have been an early socket 775 Pentium 4/D motherboard... so probably a PC from the mid-2000's. Not sure if the PSU is original to the case, but it looks like it is, based on the HP P/N stickers.

As far as lasting 15 years - well, I don't know if it did. I got the case from a guy on Craigslist for $5, as it seemed like a pretty decent spare mATX case to keep around. But I remember seeing the ad for it possibly up to 1 year prior to when I got it. I think the ad got taken down, and then went back up around this winter. So quite possibly, the case (and PSU) have sat in storage for more than a year. In fact, when I got the case, it was quite a bit dustier/dirtier than the pictures and even had a few mouse droppings. Thus, I definitely think it sat in storage for a while.

Nonetheless, I wouldn't be surprised if the caps in the PSU lasted at least 10 years. Indeed Delta knows how to make lesser brands last for a good while - or at least usually past the intended life of the PC/PSU anyways. Of course, I'm of the opinion that these PSUs can be re-used for much much longer, because they are simple and built quite well - no APFC circuit to burn primary caps after X number of years, and usually no hard-to-find "unobtanium" replacement parts, in case something does go *boom* for whatever reason... though this particular PSU did have a number of "cryptic" parts that I couldn't find datasheets for. It also has a good deal of SMD parts. This is where I like the HiPro equivalents of that age just a bit better, as they usually come with none and often have space for 12.5 mm caps on the output.

[PeteS in CA]

Re: Power supply build quality pictorial. part 2

If Delta uses the YYWW date code format the PSU is about 15 years old. Even if it hasn't been used for a couple of years someone got very decent life out of those CapXon caps. Whether good airflow or the use of lower loss -52 material, or (probably) multiple factors combined, Delta seems to get a bit better life from lesser quality output caps.

[momaka]

Delta Electronics DPS-300sb A REV:03F [PCB: DPS-300sp A]

And… looks like we're going to go back to regular ATX PSUs here… and back to Delta, too. Today's post features a DPS-300sb A REV:03F (based on PCB: DPS-300sp A.)



It almost like a deja-vu of the DPS-300KP, but then also not quite. Again, we see a clam-shell –style case. But the back vents are different. Moreover, the output connectors are a bit different too: 24-pin ATX (not 20+4 pin, BTW), 4-pin 12V CPU, 2x SATA, 5x Molex drive, and 1x floppy. Most of the wires on the 24-pin ATX and all of the wires on the 4-pin CPU connectors are 16 AWG – i.e. THICC! And in between those are a few “regular” 18 AWG, 300V wires. Really only the floppy connector uses smaller (22 AWG) wires. And just like the DPS-300KP, this one is a fairly heavy PSU too.

Moving onto the label:

Well, the 3.3V/5V combined power rating is not as impressive as on the DPS-300KP, but it's still more than enough for a retro rig at 175 Watts combined. On the other hand, the 12V rail is rated slightly better at 19 Amps. I bet it could do 20-22 Amps easily if the OCP doesn't trip, because this PSU is otherwise quite overbuilt in that area.

Speaking of which, let's start with an overall shot.

Ah, nice – it's got the same style heavy-metal heatsinks as the 300KP. Probably where most of that weight is coming from. The metal shell also has two notches for a 2nd EMI/RFI filter PCB just like the 300KP. But that wasn't installed on this PSU, because it contains all of the EMI/RFI filtering on its main PCB. And let's have a look at that:


There are two X2-caps, 2 common-mode chokes, and plenty of Y2 caps (6 total), so the EMI/RFI filter is more than adequate. For protection, besides the fuse, there are also 2x MOVs and 2x NTC thermistors. Regarding the latter, the NTCs are configured in a very interesting way: one of them is on the Neutral, right after the Neutral wire connection on the PCB (as it should be), but the 2nd (smaller) NTC is placed on the Neutral right before the bridge rectifier and can be bypassed by the voltage-doubler circuit's switch. Thus, when this PSU is used in a country with 120V, only the big NTC thermistor is used and the 2nd one is bypassed. On the other hand, when the PSU voltage switch is set to 230V, the 2nd NTC is not bypassed and adds a bit more resistance. My guess is Delta did this to lower the inrush current on 220/230/240V (which is higher than at 120V.) So to give the PSU slightly better efficiency, they used a slightly lower resistance NTC for the 1st one and then add a bit more resistance, as needed for 230V operation, with the 2nd NTC. Smart!

Next, let's have a look at what's on the rest of the primary side.

Main PS uses STF topology, but with two TO-247 MOSFETs in parallel. Meanwhile, the 5VSB uses a free-standing (not heatsinked) TO-220FP MOSFET. But this time, the 5VSB is not a 2-transistor self-oscillator. Instead, there is a PWM IC for it. In terms of transformers, main one is ERL35 with dimensions of 35x42x11 mm. 5VSB transformer is a bit on the small side, utilizing only a 16 mm wide core… but maybe with the PWM IC, it switches at higher frequency, so perhaps that's how it can get away with it. Not much else to see other than that. Primary bulk caps are CapXon LP instead of nice Rubycon's like in the 300KP… but there's no APFC here, so we can rest assured that even these CapXon caps on the primary should be OK for a few decades, at least.

Bouncing over to the secondary side…

… there's a lovely sight of brown CapXon caps everywhere. The two bulged ones are on the 3.3V rail, and I bet that's why this PSU was “abandoned”. Should be an easy fix. The more of these OEM PSUs I recap, the more I like them. This one should be pretty easy with the caps, as both the 3.3V and 5V rails use 2x 2200 uF caps each. Meanwhile, the 5VSB and 12V rails have 1x 16V, 1500 uF each. On that note, I would have liked to see a slightly bigger capacity cap on the 12V rail. Perhaps this is the reason for the 19 Amp rating. Otherwise everything else checks out to allow for a lot more. In fact, the “12V rectifier” consists of 2x SPTS20H100 Schottky diodes, where one of them is solely used for the forward rectification while the other is used solely for the free-wheeling. Therefore, this is not just a regular “parallel” setup, and I honestly expect the 12V rail to be capable of much more than 20 Amps (perhaps 25-30A with bigger output filter cap.) The 12V rail is coupled to the 5V rail too, so regulation and 12V-heavy cross-loading shouldn't be a problem… though I will test that eventually, after I recap the PSU. And both the 3.3V rail and 5V/12V common mode output toroids use the more efficient Micrometals -52 core material (with the main 5V/12V toroid being a T130-52, I think – i.e. 1.3” dia., which is quite big.)

As for the soldering…

What can I say again? Delta knows how to solder well, for sure.

Lastly, as always, is the fan.

Delta fan in a Delta PSU… Cool with me!

~~~~~~~~~~~~~~~

ICs:
“1004CL” (PWM controller main PS, primary side), “200d6” which is NCP1200 (PWM controller 5VSB, primary side), TSM1002ds (supervisor IC, secondary side), LM339 (OCP + other protections?), LM358N (OTP + fan speed?), and 7912 linear regulator (-12V rail)

Wiring:
* input: 600V, 18 AWG, EVATOP brand
* output: 300V, 16 AWG (4-pin CPU and most on ATX connector) and 18 AWG
* Output connectors: 24-pin ATX, 4-pin 12V CPU, 2x SATA, 5x Molex drive, 1x floppy

Primary Side:
* Input Filtering: two X2-class caps (2x 0.47 uF), six Y2-class caps (2x “471” on receptacle and 4x 1.0 nF on board), two CM chokes
* Input protection: F8AH250V fuse, SCK 2R512 (main) and SCK 2R55A (230V operation only) NTC inrush current limiters, 2x MOVs (1x across each cap for surge protection)
* ”0601A” bridge rectifier (too many cryptic part number in this PS already, dammit!)
* 2x CapXon LP, 200V, 680, 22x42 mm, 85°C caps
* 2x W9NK90z MOSFETs (TO-247) in parallel for main PS
* 1x F3NK80z MOSFET (TO-220FP) for 5VSB
* 1x CapXon KM, 25, 47 uF, 5x11 mm (5VSB “startup” cap, C914… and bulging)
* 1x United Chemicon KMF, 25/35V, 47 uF, 6.3x11 mm (PWM IC running cap)
* ERL35 (35x42x11 mm) main PS transformer and EEL16 5VSB transformer

Secondary Side:
*** T130(?)-52 toroid filter for 5V/12V/-12V rails
*** T103(?)-52 toroid filter for 3.3V rail (3.3V rail is mag-amp regulated)

* 5VSB
*** 1x CapXon GL, 16V, 1500 uF, 10x25 mm before PI coil
*** 1x CapXon GL, 10V, 470 uF, 8x12 mm after PI coil
*** PI coil: 3 mm core, 17-turn, 22 AWG wire
*** SB340 or SB520 Schottky diode for rectification

* 3.3V Rail
*** 2x CapXon GL, 6.3V, 2200 uF, 10x20 mm with PI coil in between
*** PI coil: 4 mm core, 6.5-turn, 14 AWG wire
*** STPS3045cw (TO-247) Schottky rectifiers
*** 2x 100-Ohm ¼ W SMD load resistors in parallel

* 5V Rail
*** 2x CapXon GL, 10V, 2200 uF, 10x30 mm with PI coil in between
*** PI coil: 4 mm core, 6.5-turn, 12 AWG wire
*** STPS2045ct (TO-220) for forward rectification + STPS3045cw(?) (TO-247) for freewheeling diode
*** 1x 510-Ohm ¼ W SMD load resistor

* 12V Rail
*** 1x CapXon GL, 16V, 1500 uF, 10x25 mm with PI coil before it
*** PI coil: 6 mm core, 13-turn, 14 AWG wire
*** 2x STPR1020ct (TO-220) Schottky rectifiers in parallel
*** 2x STPS20H100 (TO-220): 1x for forward rectification and 1x for freewheeling diode

* -12V Rail
*** 1x CapXon GL, 35V, 220 uF, 8x15 mm before 7912 linear regulator (no PI coil)
*** 1x CapXon KM, 25V, 100 uF, 6.3x11 mm after 7912 linear regulator
*** BYV27-xx (2 Amp) diode rectifier

[momaka]

Re: Power supply build quality pictorial. part 2

Back when mammoths roamed the earth and school cafeterias were serving the last of the frozen dinoburgers, Boschert (Computer Products) had a flyback model rated for 165W convection cooled or 180W forced air cooled. This model used a BJT (MJE13009s?) for the switch.

I think I've seen even larger flyback PSUs in some big CRTs from the early 2000's, rated for close to 200 Watts. So it's certainly not impossible... though in CRTs TVs and monitors, most of that power draw is from the B+, which is a fairly high voltage and low current rail, so not much filtering is needed, despite the relatively high power output.

And regarding the frozen dinoburger comment ... when I was in high-school a little over a decade and a half ago, they still served food made with frozen mammoth meat - or so it seemed, based on the taste on some of the items we had. With enough fries and ketchup, though, we would swallow just about anything.

In all seriousness, the food didn't taste that bad. Though a lot of the food items were definitely made of heavily-processed stuff. But hey, anything is better than being hungry, TBH!