$20 "500W" PSU From MicroCenter, how bad can it be?

[sam_sam_sam]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

So how do you like your new toy

How accurate is it and do you have any complaints about the quality of this product or use of this product

I might be interested in buying one for myself

I do have a question for you about the cv setting what does that function really do does it load it to keep it at a certain voltage

I just bought one for myself the other day and had some time to (test ) play with it and it seems work pretty good on a switching power supply that I had modified to work with out being hooked to a computer

I had posted the story about earlier a new twist on a switching power supply

[momaka]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

I miss c hegge

Yeah, a lot of our PSU experts/fellas are gone now, or at least not on BCN anymore is what I mean.

c_hegge, 370forlife, Pentium 4, and probably a few more. I haven't heard from Everell either. Hope everyone is alright, but perhaps not here simply because they're busy with their lives.

[goodpsusearch]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

*

On that note, maybe the PSU above should be overloaded to see what happens. (And filmed, better yet.) Where's C_hegge when we need him, though?

I miss c hegge

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Can you upgrade capacitors (from 1000uF to at least 2200uF) on the secondary to check how much ripple goes down? 250mV is absurdly high, too much even for quick tests.

Also 220uF on the primary means that, if used on 220V, we would have ~110uF. Way too low even for a 200W power supply.

Unfortunately I've already stripped it of parts and disposed of the carcass. If it was a better unit I may have tried that (like I did with the Amazon KDMPower unit). But given how bad this unit is and the lack of clearance around the caps on the secondary side not allowing for much in the way of upgrades I didn't think it was worth the effort.

[Hitto]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Can you upgrade capacitors (from 1000uF to at least 2200uF) on the secondary to check how much ripple goes down? 250mV is absurdly high, too much even for quick tests.

Also 220uF on the primary means that, if used on 220V, we would have ~110uF. Way too low even for a 200W power supply.

[Per Hansson]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Wow, I wonder if they used human hair or cat whiskers when doing clearance checks?
More seriously the soldering looks really good, the problem is the PCB routing/layout!
It is also so bizarre because it has high voltage cutout slots.
But then these clearance mistakes that makes you wonder if they thought they were designing for a 24VAC supply, not 240VAC!

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

That Rubycon looks original to me, manufactured week 43 2013.
I think the theory holds that it is a scavenged cap, how else would it be so dirty?

Yah, makes it hard to tell if they're fakes or just really faded/dirty with some of the text rubbed off from age. Either way they are either salvaged caps or phony, not good to find in a new PSU.

Did you check if the thermistor was in circuit or it is bypassed by the crap PCB/soldering?

Yes it is in circuit, the soldering while not great didn't bridge the pads:



(The arrows point to the legs of the NTC Thermistor).

[Per Hansson]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

That Rubycon looks original to me, manufactured week 43 2013.
I think the theory holds that it is a scavenged cap, how else would it be so dirty?
Did you check if the thermistor was in circuit or it is bypassed by the crap PCB/soldering?
Nice info about the DC load

Oh and I'm glad you didn't kill it with 240v with the switch set to 115v, that would be cheating

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Note: if anyone is interested, I posted a separate review of the electronic load here: https://www.badcaps.net/forum/showthread.php?t=86168 (and this time I used a PC Power & Cooling Silencer 750W with a 60A 12V rail to give it a real test).

[sam_sam_sam]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

One note if you think are fake replace if feasible and not too hard to get two

Thanks for your feedback

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

So how do you like your new toy

How accurate is it and do you have any complaints about the quality of this product or use of this product

I might be interested in buying one for myself

I do have a question for you about the cv setting what does that function really do does it load it to keep it at a certain voltage

Yes, per the manual it looks like the CV mode is intended to be used with constant current power supplies, though of course there could be other uses (disregard the voltage reference at the top of the page looks like they use the same manual for all regions, I have a 115v unit).



The quality seems decent enough for a $145 piece of test equipment. You can definitely tell it isn't "high end", the case fitment isn't the greatest, and the buttons feel a little cheap, but it seems to work well enough.






Accuracy and internal construction appears to be pretty good considering the price point:










Of course since UPS just dropped it off this morning I can't comment on long term durability.

Did you buy the DC load on Aliexpress? It looks quite nice!

Ebay, here's the link to the listing I bought it from: https://www.ebay.com/itm/30A-Dual-Ch...53.m2749.l2649, but these are all over Ebay, Amazon, etc.

Cool, will you put in some new diodes and see if you can get another component failure?
(Or, as you're in 115v land just two are in use... Heck, the PCB even has provision for a FOOL BRIDGE RECTIFIER)
Also would be cool to know if that NTC is doing anything or if it is shorted out by the PCB as it looks.
And also if those primary Rubycon caps are real or not

I have already stripped it for parts and tossed the rest.

I do have 240V in my garage/shop in addition to the normal 120V outlets, if the PSU didn't fail on its own the plan was to leave it set to 115V and hook it up to the 240V but that didn't end up being necessary.




I think the "Rubycon" primary caps from that SolidGear PSU are fakes, the coloring/font seems "off".






They do appear to actually be 220uf though testing at 212uf:

[Per Hansson]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Cool, will you put in some new diodes and see if you can get another component failure?
(Or, as you're in 115v land just two are in use... Heck, the PCB even has provision for a FOOL BRIDGE RECTIFIER)
Also would be cool to know if that NTC is doing anything or if it is shorted out by the PCB as it looks.
And also if those primary Rubycon caps are real or not
Did you buy the DC load on Aliexpress? It looks quite nice!

[sam_sam_sam]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

My new toy showed up early:

So how do you like your new toy

How accurate is it and do you have any complaints about the quality of this product or use of this product

I might be interested in buying one for myself

I do have a question for you about the cv setting what does that function really do does it load it to keep it at a certain voltage

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

My new toy showed up early:



Sadly there were no fireworks this Solid gear PSU failed with a whimper rather than a bang.

Here is right before the failure, there is 18.7A of load on the 12V rail and 10A each on the 3.3 and 5V rail for a ~307W load. As you can see the 12V rail is around 10.4V, you can't see them in the pic (since the 2 smaller electronic loads are sitting flat on the bench) but the 5V was also below 4V and 3.3V below 2V, so way out of spec. A few seconds after this it shut down never to power up again.



Analyzing the failure there are no burn marks and no blown up components. It looks like the failure point was the 4 diodes for the bridge rectifier with 2 showing completely open and one showing 2M ohms (so basically open).

[Dan81]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

I've seen such a fuse in an A-Line crap PSU.

Strange seeing them so gutless, usually most of my units were either some stupidly designed Deer (spots for PI coils but the traces didn't go anywhere) or mid-end Yuelin units (and KME, usually for their compact size PSUs),not some absolute no-name garbage.

That, and newer 2012-made Delux PSUs use a similar type of glass fuse, but in a different package. Those are at least mostly reedeemable 250W units, if you're finding soldering quite a few components in there fun (3x PI coils, common mode choke, Y cap, a X cap and that's mostly it.), whereas A-Line is best avoided, unless they're older Yuelin units (as those are semi-decent)

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Ah, right, I didn't factor that into mind. In my case, the MC close to me is literally just a 30 minute -walk- in the worst case.

Yah, MicroCenter hasn't really made its way to PA yet (with the exception of one location in the Philadelphia area) so for me it means a trip to Northern MD. (which is closer to me than Philly).

[RJARRRPCGP]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Ahh ok, I did see there was something there, but could not imagine it was a fuse so small!
Anyway it does not really matter: it is on the wrong location of the PCB.
So even if it blows the arc will probably not be interrupted and the house will burn down.
See attached photo for why, clearance, what is that for?
(The yellow rectangle is the location of the fuse, and the blue rectangle is where it should have been).

On the neutral=Immediate major violation!

[Per Hansson]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Good catch!
And OUCH, that is seriously bad cost-cutting idiocy there.

Fortunately, I don't think this can make the house wiring burn down. Look at the wires going to the voltage selector switch and also to the IEC plug - they look like AWG 22 at best. Most likely they would smoke and glow for a few seconds in the event of the fuse not working properly, but could eventually act as a secondary "fuse".


Mmmm. The smell of freshly burned PCB.

What I inferred was that the burning PCB will catch fire, not the house wiring.
Incidentally the only thing that looks decent in that PSU is the ground wire from the IEC receptacle.
That is good for when the mains wires burns off the PCB due to the fuse fuckup:
When the wire then falls against the chassis the house fuse can do its job, or much better GFCI if present
Incidentally that ground cable looks so good that I wonder if the children scavenged not only the Rubycon primary caps but also that ground cable from a decent unit at the city dump.

EDIT: Since the fuse is in the wrong location the 115/230 voltage selector switch is unfused:
https://www.badcaps.net/forum/attach...1&d=1593987874
https://www.badcaps.net/forum/attach...1&d=1593987874

[momaka]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

^This, between the thin wires from the mains connector to the PCB and those tiny little "bridge rectifier" diodes it is unlikely that this thing would be able to pull much current for very long.

I've actually blown diodes (literally) open-circuit by forcing too much current into them. (Happened on a PC motherboard on which I accidentally bumped a metal slot cover over the exposed pins of a Firewire1394 header - yeah, I was a dummy for leaving a metal slot cover at the bottom of the case loosely like that.)

The nearest MicroCenter to me is 65 mi away so it wouldn't be worth the cost of fuel to return it (I picked this up on my way back from my 4th of July holiday since I stopped for dinner in a town that has a MicroCenter).

Ah, right, I didn't factor that into mind. In my case, the MC close to me is literally just a 30 minute -walk- in the worst case.

But hey! On the other hand, at least you had the right idea: grabbing a crappy gutless PSU on the 4th of July. If it only was a PowMax, you might have even stolen the fireworks show, had you plugged it in.

As for overloading it, I recently ordered a bigger electronic load (300W) so I may do that once it shows up (right now the ETA is July 29).

Nice!

Currently... though not fully finished yet (and may never be)... I'm using a 3000 Watt Nichrome -based heater coil from a dryer as a load for testing my power supplies. Last few to test were several 15V, 7 Amp open-frame PSUs from TDK Lambda. I was able to load each to 6.85 Amps with my setup. None of them gave any issues, as expected.

On the off chance it lights up I do have a 10 lb. fire extinguisher about 5 feet from my bench, and between the fact that this is a GFCI (RCD for those of you in Europe) protected circuit (since it is a garage) which will trip itself if any current goes to ground or can also be tripped manually by hitting the test button on the outlet and the electrical panels (plural) are right above the bench killing power is a fairly quick/easy affair.

Yeah, that's plenty of precautions against fire.
What I'd be more worried about is eye safety, though. Definitely wear protective eye glasses when testing electronics like that. A fuse or silicon device shattering/exploding can send small piece of shrapnel quite far. Even with the PSU cover on, I think it's still a good idea to wear safety glasses in case something happens to go through the vents.

[dmill89]

Re: $20 "500W" PSU From MicroCenter, how bad can it be?

Good catch!
And OUCH, that is seriously bad cost-cutting idiocy there.

Fortunately, I don't think this can make the house wiring burn down. Look at the wires going to the voltage selector switch and also to the IEC plug - they look like AWG 22 at best. Most likely they would smoke and glow for a few seconds in the event of the fuse not working properly, but could eventually act as a secondary "fuse".

^This, between the thin wires from the mains connector to the PCB and those tiny little "bridge rectifier" diodes it is unlikely that this thing would be able to pull much current for very long.

Also as long as the house wiring is up to code the circuit breaker (15A on a 14 AWG circuit or 20A on a 12AWG circuit) will trip to protect the wiring, so the only potential of fire should be inside of the unit itself.

Actually, if you do that, you should also try to return the PSU to MicroCenter afterwards and say it went bad in your system. Depending on the MC near you, most will take it back and return your money, no questions asked - kind of like Home Depot returns, really. Besides, I don't see a warranty sticker anywhere. Or was there one that needed cutting/removing? If yes, that might complicate the return (or not, if you did a stealthy enough job. ) Not that I'm implying anyone should commit fraud, as this could be considered as so... but this PSU is already committing fraud, given how terrible it is.

The nearest MicroCenter to me is 65 mi away so it wouldn't be worth the cost of fuel to return it (I picked this up on my way back from my 4th of July holiday since I stopped for dinner in a town that has a MicroCenter).

As for overloading it, I recently ordered a bigger electronic load (300W) so I may do that once it shows up (right now the ETA is July 29).

On the off chance it lights up I do have a 10 lb. fire extinguisher about 5 feet from my bench, and between the fact that this is a GFCI (RCD for those of you in Europe) protected circuit (since it is a garage) which will trip itself if any current goes to ground or can also be tripped manually by hitting the test button on the outlet and the electrical panels (plural) are right above the bench killing power is a fairly quick/easy affair.