the gutless, bloated, and fried power supply hall of shame

[RukyCon]

Re: the gutless, bloated, and fried power supply hall of shame

Here we have a USB power supply that i got for free.
Here is the label...

Looking good [in a bad way.]
Seems to have the classic 100v to 240v input rating.
Note that the output voltage is 4.5V to 9.5V! That seems to be a bit high for a USB power supply.
Next up, the board itself.

Note that the ceramic capacitor is not a Y-class capacitor.
And by the way it looks. The output is is unregulated. [Explains the 4.5v to 9.5v output rating.]
The big transistor is a 13003D and the smaller one is a C945.
Bottom of the power supply.

What else do you expect from a piece of crap.
Last but not lest.

Input: 4.7uf 400v
Bootstrap: 0.33uf 50v
Output: 470uf 16v
Brands: all Y.U.B
Overall this thing is a piece of crap and should be burned.

[PeteS in CA]

Re: the gutless, bloated, and fried power supply hall of shame

... Overall this thing is a piece of crap and should be burned.

Well, plug it in and see if it self-immolates, .

[RukyCon]

Re: the gutless, bloated, and fried power supply hall of shame

Well, plug it in and see if it self-immolates, .

I really hope that happens.

I'm thinking of doing a stress test on this unit and see how much power it can really handle before burning up. [That's if the voltage doesn't drop out under load.]

[eccerr0r]

Re: the gutless, bloated, and fried power supply hall of shame

I've gotten one of those types of PSUs before, it's the el-cheaped out design that's missing the feedback loop to reduce costs.

Even worse, the one I have has a half wave rectifier primary... talk about bad PF.

[jazzie366]

Re: the gutless, bloated, and fried power supply hall of shame

I've gotten one of those types of PSUs before, it's the el-cheaped out design that's missing the feedback loop to reduce costs.

Even worse, the one I have has a half wave rectifier primary... talk about bad PF.

What? That has full wave bridge rectification? There are 4 diodes right outside the AC input.

[RukyCon]

Re: the gutless, bloated, and fried power supply hall of shame

Here we go again with another cheap 5v supply.
Label.

At lest it has a brand this time. [Brand: Just Wireless.]
Note that the input voltage is 12VDC.
Top side.

Yet again the ceramic caps are not Y-class capacitors.
The big transistor is a 13003D and the smaller one is a C945. [This is just a copy and paste of from the last one because they're literally the same.]
Bottom side.

Isolation? We don't need none of that bull. Look, it works fine without it.
Capacitor shot.

Input: 4.7uf 400v
Bootstrap: 0.33uf 50v
Output: 470uf 16v
Brands: Y.U.B [The same Y.U.B from last time.] JAKEC, And whatever that last one is.

I think this thing deserves to be burned more than the last one i took a look at.

[goontron]

Re: the gutless, bloated, and fried power supply hall of shame

I've got my "test" rig built. Ill post the designs after I give mine an "extreme overtemp cutout" test.

[lti]

Re: the gutless, bloated, and fried power supply hall of shame

That Just Wireless thing looks familiar. It appears to be isolated (poorly), unlike the one I posted a long time ago. I wonder if it would really run on 12V.

[lti]

Re: the gutless, bloated, and fried power supply hall of shame

The Just Wireless charger I posted a long time ago actually runs on 12V, but its output drops below 4.5V at about 2.5mA. It had the same input and output voltage rating.
Pictures (from 2014) for reference:
https://www.badcaps.net/forum/attach...5&d=1401588349
https://www.badcaps.net/forum/attach...6&d=1401588349

I missed the isolation gap for all these years. There is no copper under that white line on the bottom. I turn stupid every time I go near this thing.

Those two ceramic caps are not in a position where they need to be safety rated. C6 (on both power supplies) would need to be safety rated if it was populated.

[Per Hansson]

Re: the gutless, bloated, and fried power supply hall of shame

Those two ceramic caps are not in a position where they need to be safety rated. C6 (on both power supplies) would need to be safety rated if it was populated.

I noticed this as well but was too occupied to respond.
I find it really strange how some PSU manufacturers put in these non-safety rated caps.
Why not just do the right thing (like here) and put nothing there?
A hell of allot safer than having something that can put mains voltage on the USB connector!!!
And for everything the companies making these care about: cheaper too!

[RukyCon]

Re: the gutless, bloated, and fried power supply hall of shame

I'm thinking of doing a 'Running while it's on fire' test on the just wireless power supply and a 'High voltage' test on the generic one by putting a MOT across the input and output.

[ben7]

Re: the gutless, bloated, and fried power supply hall of shame

Coworker brought to me a Chicago Electric 2kW inverter (model 92464) that he picked up for $30. He wanted my opinion as to how well built it is ...

First off, note that it is a two-board design. The big board is the 12V to HV (probably around 170V or so) booster. The smaller board is the main controller, which also has 8 IGBTs on it for the DC to AC conversion. It's probably modified sine wave output because there is no output filtering inductor/capacitor (in fact not even EMI filtering!). The capacitors are the cheapo "GL" brand - the DC input caps are 2200uF 35V and the HV rail caps are 470uF 200V.

Oh, and, notice the two red arrows? Those point to the cables that control the booster switching FETs. Yikes! Those long, thin wires mustn't be good for high frequency switching (and at high currents too, because there are a total of 16 FETs! I checked the bottom of the booster board and there are no drivers on that board... crazy design!).


Next up ... um, woah!!!
LOL, this is why he picked it up for only $30 ...


Yes, all eight (8!) 30 amp fuses are blown!
Interestingly I can't see any scorch marks around the FETs, but I bet they are blown. I didn't even bother testing them because this thing is going to go back for a refund, LOL.

-Ben

[Dannyx]

Re: the gutless, bloated, and fried power supply hall of shame

Not liking the way the live and neutral wires are botched onto the PCB on the left either...should be properly crimped spade connectors IMO.

[momaka]

Re: the gutless, bloated, and fried power supply hall of shame

GL caps are awesome!........................................... at failing
Even if this thing was designed properly, those caps would have brought it down.

There's a reason why some stuff from Harbor Freight are so cheap.
Hopefully your friend should know better now.

I myself shop there only for certain items that I know the quality doesn't matter to much, like cheap garden work gloves and paint brushes. Occasionally, they do have a few decent things - got a decent breaker bar for my car from there and also the "3-ton" jack stands (which probably won't hold up to 3 tons for sure, but I have a small light car, so those are okay for that).

[RukyCon]

Re: the gutless, bloated, and fried power supply hall of shame

I can tell you from my personal experience that GL caps are crap.

I bet that thing can't output the full 2KW that it says it can do, maybe 500Watts or less.

[jazzie366]

Re: the gutless, bloated, and fried power supply hall of shame

Your shitting me? Undersized and knockoffs of a Crapacitor brand? Vhat the fuck?

Well actually, ChengX and Chang caps may or may not be bad caps. Chang caps made large appearances in older CRT tvs, and monitors. They're really common in certain older Samsung TVs. Forgot the exact model, but there was one by Samsung that was entirely Chang branded, 3 were known to fail and cause the TV to act up, but this was well after it's lifespan.

As for ChengX, fakes of these are extremely common. Real ChengX caps can be found in power supplies made by Honglin, a common OEM for USB chargers. I have one that is for an old android tablet I got when I was first starting college in 2014. It's still going today, no bloating or loss of capacitance or bad ESR.

I'm really unsure of the caps nature, but from what I've seen there is some small proof they might just have tarnished names.

I uploaded datasheets to the depot, if you have a look at them, you can see pics in them of the real caps. Real ones should have a lot/size code (can't tell) such as "16D", model (such as GR) and the word "VENT" correctly spelled. Fakes commonly have the word, "VEHT" written on them.

The ChengX should also look like this:


OR

[eccerr0r]

Re: the gutless, bloated, and fried power supply hall of shame

That inverter probably could support 2KW, it's big enough.

However the fuse thing is kind of bothersome. Just like transistors, you can't really parallel fuses together either and that's why things like this happen. However people still do it.

I have a 400W inverter that uses three 30A fuses in parallel. That's way overkill, but due to the paralleling problem, it's not really that much overkill. And just like that 2000W inverter, my inverter will also blow all (three) fuses if there's an overload. Fortunately the switching transistors were saved by the fuses.

[eccerr0r]

Re: the gutless, bloated, and fried power supply hall of shame

(And btw Chongx or Chqngx is a bad cap...)

[Dan81]

Re: the gutless, bloated, and fried power supply hall of shame

I don't have pics (my phone battery's dead and for some reason the two USB cables I have won't work with the genuine Samsung charger I have) but I just got a PSU today.

It's some noname "400W-PIV" PSU that came with a PC I gutted. I initally thought this was a random crappy Leadman with ultra-thin heatsinks, then a Kaisen because of the thin heatsinks.

It turned out to be a pretty beefy Sun Pro. D209L primary transistors, true ERL-35 transformer (I easily recognize a ERL35 transformer so I can confirm it's a true ERL35) and a VERY thick output coil.

Other than that, of course, it had bulging SC caps, including on the 5vSB rail too. I'll definitely recap this though. This, and the output filtering is missing, but at least it has VERY thick diodes. (I don't really care if it uses diodes or a bridge rectifier - it's all about them being powerful).

[Wester547]

Re: the gutless, bloated, and fried power supply hall of shame

Well actually, ChengX and Chang caps may or may not be bad caps. Chang caps made large appearances in older CRT tvs, and monitors. They're really common in certain older Samsung TVs. Forgot the exact model, but there was one by Samsung that was entirely Chang branded, 3 were known to fail and cause the TV to act up, but this was well after it's lifespan.

CRT TVs / monitors aren't nearly as hard on their caps as LCD TVs / monitors are.

As for ChengX, fakes of these are extremely common. Real ChengX caps can be found in power supplies made by Honglin, a common OEM for USB chargers. I have one that is for an old android tablet I got when I was first starting college in 2014. It's still going today, no bloating or loss of capacitance or bad ESR.

Heh, it's only 3 years old. The real test of any bad cap is time.

I uploaded datasheets to the depot, if you have a look at them, you can see pics in them of the real caps. Real ones should have a lot/size code (can't tell) such as "16D", model (such as GR) and the word "VENT" correctly spelled. Fakes commonly have the word, "VEHT" written on them.

One could also chalk that up to the inconsistency that is characteristic of many bad crap brands.