Re: the gutless, bloated, and fried power supply hall of shame
I'm going to concur with momaka, the big lytics probably failed when one of the rectifiers in the bridge shorted and the caps saw reverse voltage. While the label value of 470uF in that configuration would probably be OK for 250W, that inverter heatsink puts the useful power (if operating) at around 200W. And if the rest of the PSU is as skimpy as the non-existent power line filtering, that might be pushing it. It might not even have many parts worth salvaging.
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by momaka View PostAlso, for half-bridge PSUs, you must have two series caps on the input. That way, the input voltage is divided equally. The "center tap" or "middle connection" of these series caps goes to one side of the main PS transformer on the primary (through a metal film cap). The other leg on the primary side of the main PS transformer is switched between +340V and primary GRND by the two BJTs. So this creates a series of square wave pulses with 170V amplitude across the main PS primary side. On the secondary side, you have center-tapped windings for a 5V rail and 12V rail, from which the 3.3V, 5V, 12V, -5V, and -12V rails can be derived.
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Re: the gutless, bloated, and fried power supply hall of shame
Oh man, that ^... is soo gutless!
Even if the PSU didn't have any damage, I would NOT use it for anything - not even powering small DC fans.
Originally posted by Dannyx View PostSeverely failed mains caps on a trash-picked RPC ATX supply.
...
Two diodes of the bridge were shorted.
...
The fan was not seized when I found it (so I kept it ), so the cause of failure wasn't actually excess heat, but likely overvoltage !
I don't see an input voltage selector switch, so it's not possible for someone to have set the PSU for 115V AC operation and then plug it into 230V AC (which is one way to cause this kind of damage to the primary caps.)
Instead, it looks like either one or more of the diodes in the full "bridge rectifier" on the input overheated and shorted, sending AC current to the input caps...
-OR-
There was a power surge from nearby lightning strike hitting a power line and causing massive over-voltage.
I imagine this PSU came from the city, where majority of AC power distribution to residential buildings is underground. So that means caps likely blew because the diodes in the bridge rectifier failed.
Originally posted by Dannyx View PostLook at those caps more carefully: only 200v rating ? There's no PFC here, so although B+ doesn't go as high as 400v, I know for a fact it's still around 300+ after the bridge rectifier, making a 200v rated cap about 100v too low ! Could it be they're in series ?
Also, for half-bridge PSUs, you must have two series caps on the input. That way, the input voltage is divided equally. The "center tap" or "middle connection" of these series caps goes to one side of the main PS transformer on the primary (through a metal film cap). The other leg on the primary side of the main PS transformer is switched between +340V and primary GRND by the two BJTs. So this creates a series of square wave pulses with 170V amplitude across the main PS primary side. On the secondary side, you have center-tapped windings for a 5V rail and 12V rail, from which the 3.3V, 5V, 12V, -5V, and -12V rails can be derived.
Originally posted by Dannyx View PostAlso, have a look at that top "shelf" of the heatsink. Yes, that's right: the force of the can being "ejected" upwards was so great that it bent the corner of the heatsink. I myself wouldn't be able to do that bare-handed
I have an old L&C/Deer PSU, whose unfiltered high-side 5VSB cap exploded and also bent a fin on the secondary-side heatsink, just like on your unit.
Give me a few minutes, and I'll edit this post with a link to that PSU (I posted it on BCN many many years ago.)
**EDIT**
Here is the PSU/picture in question:
https://www.badcaps.net/forum/attach...2&d=1331835289
Notice the two "ears" sticking out on a component? (Just a little left from the center of the image.) Those are the leads and rubber bung left from that exploded cap. The cap can probably hit the heatsink fin right above it and bent it. I couldn't find the cap can body anywhere, though. It must have fallen out when I found that PSU (it was a trash can find many years before I was even into fixing electronics.) There was simply paper and aluminum shrapnel/shards/pieces everywhere inside the PSU. This is why I always wear safety glasses when testing PSUs with covers removed or when testing a circuit on my breadboard that involves small caps and the possibility of them getting either over-volted or reverse-voltage (though I usually design to try to avoid that, of course.)
Here is the post I made about it, from 8 years ago, mind you (wow I feel old now! )
https://www.badcaps.net/forum/showpo...&postcount=489Last edited by momaka; 06-13-2020, 10:58 AM.
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Re: the gutless, bloated, and fried power supply hall of shame
Severely failed mains caps on a trash-picked RPC ATX supply. I dug this out of our junk pile the other day with intent of scavenging for parts, when I saw THIS The vent on the cap on the left apparently failed to open up, forcing the pressure to release out the bottom. Fuse was completely blown to bits (visible to the right). Two diodes of the bridge were shorted. BJTs were OK, so likely fixable overall, but what's the point when the caps cost almost as much as the whole thing when new ?
Also, have a look at that top "shelf" of the heatsink. Yes, that's right: the force of the can being "ejected" upwards was so great that it bent the corner of the heatsink. I myself wouldn't be able to do that bare-handed
The fan was not seized when I found it (so I kept it ), so the cause of failure wasn't actually excess heat, but likely overvoltage ! Look at those caps more carefully: only 200v rating ? There's no PFC here, so although B+ doesn't go as high as 400v, I know for a fact it's still around 300+ after the bridge rectifier, making a 200v rated cap about 100v too low ! Could it be they're in series ?.....but that would also drop capacitance ! I tossed the board now, so I forgot to check, for curiosity's sake. TBH, I didn't even notice that 200v marking until just now when I was transferring the photos off my phone to upload them Am I mad ? 200v caps on the hot side of a SMPS ? Is it intended for a 110v country ? Maybe they were in series after all....:|Last edited by Dannyx; 06-13-2020, 07:09 AM.
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Re: the gutless, bloated, and fried power supply hall of shame
Yeah, that Lametech looks like it could be a usable 200W P/S - limited by the 330uF F-yus, where's-the-beef heatsinks, under-sized main transformer, wimpy output rectifiers, almost-tiny toroids and AWG #20 output wires. It looks like its Y-caps are safety rated types, though.
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Re: the gutless, bloated, and fried power supply hall of shame
Yeah, that's the same platform used in MOST Delux units. Pretty moddable if you ask me. I've actually improved one of these for a quite low power i3 unit w/ GTX1050 (w/o PCI-E plug, MSI branded) and it's been holding up great.
Ironically HKC PSUs did a better attempt at this, and if it weren't for the quite skinny heatsinks in mine, it might actually do 430W.
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by goodpsusearch View PostLamtech ATX-S450
Personally, I find this psu boring.
While most of the components are there, they are just too small.
Looks like a decent *try*, but just a tad bit short of being overall decent PSU.
15A on the 12V rail will do for a basic system, if it can provide that much in spec. With 2 output caps and a PI coil, it probably will - just barely, if the caps on the 12V rail are 1000 uF each (and they look like they are.) Still, it ticks me off to see a 450 Watt rating on the label. If they advertised this as a basic 200-250W PSU and sold it for the right price, this would be much better alternative than, say... Powertech or L&C.
Originally posted by goodpsusearch View PostThe primary caps are 330uF, too small to take this unit seriously and who knows if this is their real capacitance.
Originally posted by TechGeek View PostMore like LAMEtech
Still better than L&C (Lame and Crappy )
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Re: the gutless, bloated, and fried power supply hall of shame
More like LAMEtech
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Re: the gutless, bloated, and fried power supply hall of shame
Lamtech ATX-S450
Personally, I find this psu boring.
While most of the components are there, they are just too small.
The input filter is here, missing a common mode choke and MOV.
The conductive glue is here too. Good!
The 4 diodes are tiny but probably good for 230V AC.
The primary caps are 330uF, too small to take this unit seriously and who knows if this is their real capacitance.
half bridge design with switching transistors 2x D13007
very small transformers 33 and 16
nicon caps everywhere
pi coil for every output voltage and 2 caps for all voltage rails except -12V
tl494 and SDC339 ICs
very small toroid coils
S16C45C @ 3.3V
S20C45C @ 5V
F16C20C @ 12V
This unit was made in 2011 and looking at the label:
15A @ 12V
there is no excuse for that
The label also states that there is -5V rail and the white cable is there, but the place for -5V output cap is not populated on PCB.
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by goodpsusearch View PostBeware! The most powerful Powertech power supply ever posted here!
Powertech ATX-550W
Well, compared to the other Powertech PSUs, it indeed has really good build quality. (Not that they were setting the bar too high to begin with. )
Originally posted by goodpsusearch View Postlabel states dual 12V rail and 17A on each one with no max combined output limit!
If only they gave it an honest 250W rating with maybe a limit of 200W on the 12V rail, that PSU wouldn't actually been half bad.
Originally posted by goodpsusearch View PostThe fan brand is "Cooling fan". Cool
Originally posted by goodpsusearch View PostThere is also a full input filter, except the MOVs because they are expensive!
Originally posted by goodpsusearch View PostThis unit broke the chinese tradition and even has an IC controlled 5vsb :
em311Z
I searched but couldn't find a datasheet.
https://cdn.badcaps-static.com/pdfs/...0ea56a5952.pdf
Check if the pinout matches.
Probably does. I don't see what else it would be.
Not bad. Everell here did a mod like that to convert many Bestec ATX-250-12E power supplies, and it works pretty well. Will handle up to 2-2.5 Amps
Originally posted by goodpsusearch View Postand the rectifier for 12V is mur2020ct, rated for 20A.
Originally posted by goodpsusearch View PostAnd there is a fan controller with thermistor ghetto glued on secondary heatsink
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Re: the gutless, bloated, and fried power supply hall of shame
Beware! The most powerful Powertech power supply ever posted here!
Powertech ATX-550W
label states dual 12V rail and 17A on each one with no max combined output limit!
The fan brand is "Cooling fan". Cool
There is also a full input filter, except the MOVs because they are expensive!
Originally posted by Per Hansson View PostHow is the 5VSB on these units, is it "two transistors" design or something decent?
em311Z
I searched but couldn't find a datasheet.
half bridge psu with 2x 13007 again
the rectifiers for 3.3V and 5V are MBR2545CT
and the rectifier for 12V is mur2020ct, rated for 20A.
So, it is indeed really powerful compared to the other Powertech units.
And there is a fan controller with thermistor ghetto glued on secondary heatsink
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by bauto601 View PostThe TO247 12V rectifier also did not fit since the board only allows TO220 parts there, so i had to bend the legs of the rectifier and make a new mounting hole on the heatsink to mount it higher in order to make it all fit.
With other gutless PSU's I've seen (particularly ones that were based on a "high end model" PCB and then made cheaper), they would have TO-247 holes, but only TO-220 parts installed, with the TO-220 parts' pins stretched to fit the holes, lol.
Originally posted by goodpsusearch View PostPowertech ATX-450W year 2014
...
Something bad happened here as you can see from the toasty group of resistors.
Originally posted by goodpsusearch View Postwhy? I mean, this is not an early 00s unit. It's a 2014 psu. Why put 20A and 30A on 3.3V and 5V rails and 12A ultrafast rectifier on 12V?
Originally posted by Per Hansson View PostI don't think the manufacturer cares much considering this unit would require PFC to be sold in the EU though, yet there is none.
And since it is rated for 230VAC input only I guess they had no plans to sell it anywhere else...
But yeah... not like the manufacturer seems to care anyways.
Originally posted by Per Hansson View PostHow is the 5VSB on these units, is it "two transistors" design or something decent?
Like I said... old Chinese traditions must be observed.
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Re: the gutless, bloated, and fried power supply hall of shame
Well the label on the powewr (sic) supply is what informed people base their purchasing decisions on.
And that assures of a hefty 29A on 12v, and then just 10A on 5v and 14A on 3.3v.
Sounds like a quite modern unit don't you think?
I mean we have come a long way comparing it to the label on this don't you think?
It is almost like they have listened to your initial feedback there and then made some serious iterations.
In this latest one is the PFC connector spot maybe even upgraded so it sits between live a neutral and not just off to the side not connected to anything?
I don't think the manufacturer cares much considering this unit would require PFC to be sold in the EU though, yet there is none.
And since it is rated for 230VAC input only I guess they had no plans to sell it anywhere else...
How is the 5VSB on these units, is it "two transistors" design or something decent?
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Re: the gutless, bloated, and fried power supply hall of shame
Powertech ATX-450W year 2014
I have also the 2012, 2013 and 2015 versions of this thing.
No one is even close to half decent.
Something bad happened here as you can see from the toasty group of resistors.
2x 13007 npn transistors
EST7502C supervisor IC
MBR2545CT 3.3V
MBR2060CT 5V
F12C20C 12V
why? I mean, this is not an early 00s unit. It's a 2014 psu. Why put 20A and 30A on 3.3V and 5V rails and 12A ultrafast rectifier on 12V?
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by RukyCon View PostThis looks like an Athena Power unit, definitely better than the one i pulled about 2 years ago as yours seems to have more room for modifications.
And talking about room for modifications... The second cap for the 12V rail is added at the place where you normally put the outgoing wires. The PFC connector is not mounted directly to the PCB as they never even bothered to add PFC support on it. The bigger output inductor did not really fit and i had to use some additional solid core wiring and modify the secondary heatsink to make it fit, the ERL35 transformer had the same footprint as the ERL33 transformer and even that one i had to squeeze in and change the primary heatsink for. The TO247 12V rectifier also did not fit since the board only allows TO220 parts there, so i had to bend the legs of the rectifier and make a new mounting hole on the heatsink to mount it higher in order to make it all fit. The fan control circuit is also added via an additional PCB, at least the bridge rectifier popped right in.....Last edited by bauto601; 05-18-2020, 03:51 PM.
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Re: the gutless, bloated, and fried power supply hall of shame
This looks like an Athena Power unit, definitely better than the one i pulled about 2 years ago as yours seems to have more room for modifications.
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by momaka View Posthmmm.
If it was my unit, i would have put that 2200 uf cap on the 5vsb rail. 5vsb caps see far more stress than any other rail, since it is always on and filters a flyback design (higher ripple current output.)
the -12v rail no one cares about. Just has to be there and not too out of spec to trip uv/ov protections. Same goes for the -5v rail.
Originally posted by momaka View Postanother option you can do if you want to keep the -5v rail (for legacy purposes) is to install a 7905 voltage regulator and use the -12v rail to generate -5v with the 7905 regulator. Plus, it's easy - just mount the 7905 on the secondary heatsink and run wires from -12v, -5v, and grnd to the appropriate pins.
Originally posted by momaka View Postthose are not bad results at all. Pulling 220 watts from the 12v rail is actually impressive given how compact this unit is. Not surprised at all with the temperatures. Now put it in a core 2 duo box that uses no more than 100 watts, and this psu will probably have a very long life and run much cooler.
The pcb traces are fairily short because of the small pcb, filling the main power traces on the secondary side with solder tin also helped a bit i think. This helps the voltage regulation too.
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Re: the gutless, bloated, and fried power supply hall of shame
Originally posted by goodpsusearch View PostDeer DR-8500BTX (MAX 500W)
not able to output any watts in specs here
And it's a shame, because the primary side probably could do 200-250 Watts. With good parts on the secondary and proper filtering, even a 200-250 Watt PSU can be plenty for many office systems and entry-level gaming PCs.
Originally posted by bauto601 View PostI mean, they really went out of their way for this one and did all kinds of extra work to still produce a shitty PSU.
- Added a seperate PCB for input filtering
- 4 "fat" diodes for input rectifier bridge
- real output rectifiers, no "2-diodes-on-a-plate" jobby
- The caps were good enough to last for a couple of years it seems
- A label completely dedicated to this one PSU version
I mean, they even painted the case and glued the fuse down. That's some serious build quality you don't expect from a Deer unit.
Originally posted by Hemingray View PostThese crapbox PSUs still exist in 2020?
As long as there are suckers to buy them (and believe me, there are - especially in this day and age where buying questionable cheap Chinese products from eBay and Amazon is considered a norm), we will keep seeing them.
Originally posted by PeteS in CA View Postbut if those "Y caps" are generic 1KV or 2KV DC parts instead of agency-approved safety caps, .
Originally posted by goodpsusearch View PostForce DR-8460BTX (MAX 450W) v2.2
The fan stopped but the psu continued working till it almost burnt itself to death.
I wonder what this PSU was powering for so long, though. You'd think with that crappy filtering and bad caps, the constant PC crashes/instability would have made the owner realize something is wrong with the PSU and replaced it.
Instead, it was ran until it turned into Deer kebab.
Originally posted by bauto601 View PostI recently bought 2 shallow ATX power supplies, hoping that they were better than the YoungYear unit i'm currently using. Unfortunately that wasn't the case...
The PCB layout however did have some potential for becoming a decent compact unit. After pulling some components from some other (broken) power supplies, i did the following upgrades:
...
+5VSB: 1x 470uF 16V ChengX, not looked any further -> same
-12V: 1x 470uF 16V ChengX, NO PI Coil -> 1x 2200uF 16V Teapo SC, added PI Coil
If it was my unit, I would have put that 2200 uF cap on the 5VSB rail. 5VSB caps see far more stress than any other rail, since it is always On and filters a flyback design (higher ripple current output.)
The -12V rail no one cares about. Just has to be there and not too out of spec to trip UV/OV protections. Same goes for the -5V rail.
Originally posted by bauto601 View PostAfter making all these changes, it didn't start anymore. It turned out that the controller was entering a protection. The bigger output inductor did not have a winding for the -5V rail. Now, that isn't a problem since modern hardware does not use this voltage rail anymore. But the controller was entering it's UVP protection for the negative rails. Connecting the supervising pin for these negative rails directly to ground fixed it.
Originally posted by bauto601 View PostI've done a quick 15 minute stress test run with the following hardware:
- Intel Pentium D overclocked to 4GHz with 1.45Vcore (used this as the variable load)
- Gigabyte X48T-DQ6
- 4x2GB RAM
- NVidia Geforce GT640
- 2x IDE HDD
Using a current clamp i got the following load numbers:
12V (12.09): 18.5A / 222W
5V (4.99): 5A / 25W
3.3V (3.25): 8A / 26.5W
Total power: 273.5W (~275W)
...
Temperature wise, the power supply could probably use a bigger secondary heatsink, the fan ramps up nicely:
60c Primary heatsink
60c Transformer
75c Secondary heatsink
80c Output inductor
PFC coil: Toasty
I can call it a win this time.Last edited by momaka; 05-18-2020, 12:08 PM.
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Re: the gutless, bloated, and fried power supply hall of shame
I recently bought 2 shallow ATX power supplies, hoping that they were better than the YoungYear unit i'm currently using. Unfortunately that wasn't the case...
The PCB layout however did have some potential for becoming a decent compact unit. After pulling some components from some other (broken) power supplies, i did the following upgrades:
NO PFC -> Passive PFC
2x Y capacitor -> same
NO X capacitor -> added X capacitor
1x common mode choke -> 1x better wound common mode choke
2x 2.5A diode -> KBL406 rectifier bridge
2x 4A diode -> see above
2x 470uF 200V Ltec primary caps -> same
2x 13007 primary transistors -> 2x D304X primary transistors (still TO220)
1x SVD2N60F mosfet -> same (but primary heatsink has been swapped)
ERL33 transformer -> ERL35 transformer (swapped the primary snubber circuit together with it)
Small output inductor -> bigger output inductor
SC6105 switching controller -> who would swap a controller? Not me
NO fan control -> added fan control
12V: MOSPEC F16C20C 16A TO220 Fast Recovery rectifier -> DSSK 40-008B 40A 80V TO-247 Schottky rectifier
5V: MOSPEC S30D45CS 30A TO247 Schottky rectifier -> same, 5V is already beefy enough
3.3V: Advanced Power AP40N03GP 40A mosfet (tapped from 5V) -> same, also beefy enough
12V: 1x 1000uF 16V ChengX, PI Coil -> 1x 2200uF 16V Teapo SC, 1x 470uF 16V ChengX, PI Coil
5V: 2x 1000uF 10V ChengX, PI Coil -> 2x 3300uF 6.3V Panasonic FS, PI Coil
3.3V: 1x 1000uF 10V ChengX, PI Coil -> 1x 3300uF 6.3V Panasonic FS, PI Coil
+5VSB: 1x 470uF 16V ChengX, not looked any further -> same
-12V: 1x 470uF 16V ChengX, NO PI Coil -> 1x 2200uF 16V Teapo SC, added PI Coil
-5V: 1x 470uF 16V ChengX, NO PI Coil -> still there, just not used anymore
After making all these changes, it didn't start anymore. It turned out that the controller was entering a protection. The bigger output inductor did not have a winding for the -5V rail. Now, that isn't a problem since modern hardware does not use this voltage rail anymore. But the controller was entering it's UVP protection for the negative rails. Connecting the supervising pin for these negative rails directly to ground fixed it. The voltage selector switch on the rear is also removed in order to make room for the PFC coil
I've done a quick 15 minute stress test run with the following hardware:
- Intel Pentium D overclocked to 4GHz with 1.45Vcore (used this as the variable load)
- Gigabyte X48T-DQ6
- 4x2GB RAM
- NVidia Geforce GT640
- 2x IDE HDD
Using a current clamp i got the following load numbers:
12V (12.09): 18.5A / 222W
5V (4.99): 5A / 25W
3.3V (3.25): 8A / 26.5W
Total power: 273.5W (~275W)
Using my PR10 power meter, i got the following numbers from the socket:
Power: 340W
Voltage: 221V
Current: 2.0A
Power Factor: 0.76
Efficiency: 275/340 = 0.81 = 81% (pretty decent, that's probably 220VAC doing it's magic)
Temperature wise, the power supply could probably use a bigger secondary heatsink, the fan ramps up nicely:
60c Primary heatsink
60c Transformer
75c Secondary heatsink
80c Output inductor
PFC coil: Toasty
I can call it a win this time.Last edited by bauto601; 05-18-2020, 07:40 AM.
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