Question about 12V/5V 2A Power Supply (Sparkfun example)

Other Hardware Motors, Mechanics, Power and CNC
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I have a power supply brick like this one on sparkfun: Power Supply - 12V/5V (2A) - TOL-15664 - SparkFun Electronics Looks like the same exact unit for the most part, probably both come from the same chinese company. You may notice my comment in reply to someone on Sparkfun, but figured I might be better off asking for an answer on here.

Something like this would work nicely on my current project where I need 12v 500mA of power for one thing in my project, but the rest of my project only needs 5v / 3.3v and probably 200 to 400 mA (haven't finished it yet so don't know the total on that yet). But there are a few comments about problems with these adapters not being reliable and the one that I replied to about it fried disk drives.

Does anyone have experience with one to know what causes this? Is it the voltage regulators in the brick aren't very good and let to much voltage through, or are surges causing a problem or something like that? I don't want to finish my project and put it in permanent place just to have the power supply fry it after a week or two. I could put additional voltage regulators / fuses in my project if I need to, but if there is another better supply that isn't to expensive that can serve the same purpose I might just use that.

Thanks!

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Anyone one can say anything they want on the internet, doesn't make it factual or not factual. I would not think this ps is any more or less reliable then any similar Asian ps. Sparkfun will stand behind the product as good as any other product they sell. Go for it, it's a very good price in my opinion.

Lefty

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retrolefty:
Anyone one can say anything they want on the internet, doesn't make it factual or not factual. I would not think this ps is any more or less reliable then any similar Asian ps. Sparkfun will stand behind the product as good as any other product they sell. Go for it, it's a very good price in my opinion.

Lefty

It's not simply a matter of them standing behind the product. As I said I already have one in fact. It's more about the rest of my project getting fried by it. I couldn't care less if sparkfun stood behind a 10 dollar product when 150 dollars worth of other electronic components was fried by it.

That is what I mainly trying to find out, what might cause such a thing so that I can make sure to take proper precautions against it. If the power supply of this type is less reliable than others then I'd rather go with one that is more reliable.

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That is what I mainly trying to find out, what might cause such a thing so that I can make sure to take proper precautions against it. If the power supply of this type is less reliable than others then I'd rather go with one that is more reliable.

Well then you had better not buy it as there is no way someone can give you a guarantee you are implying for, nor can anyone vouch for the accuracy of the comment you read. You could always put fixed resistor (or lamp?) loads on the PS and let it burn in for some time until you have confidence in it.

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An alternative would be a PICO PSU
http://www.ebay.co.uk/itm/Pico-PSU-12V-120W-DC-DC-MINI-ITX-ATX-Power-Supply-PC-/160860474433?pt=PCA_UPS&hash=item2574080c41

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retrolefty:

That is what I mainly trying to find out, what might cause such a thing so that I can make sure to take proper precautions against it. If the power supply of this type is less reliable than others then I'd rather go with one that is more reliable.

Well then you had better not buy it as there is no way someone can give you a guarantee you are implying for, nor can anyone vouch for the accuracy of the comment you read. You could always put fixed resistor (or lamp?) loads on the PS and let it burn in for some time until you have confidence in it.

Actually, anyone who has experience with the unit in question could vouch for the accuracy of the comments I read by saying whether or not they have experienced similar problems.

And I didn't say anything about looking for a guarantee, I didn't even imply it. Once again, I don't know if you are just overlooking this or can't understand or what, I'm not interested in whether or not I should buy it, I've already got a similar / same unit from a purchase I've made previously at newegg. Not sure what your reference to lamp is, the only thing I know for lamp is the acronym linux apache mysql perl.

My original questions remain, Does anyone have experience with one to know what causes this? Is it the voltage regulators in the brick aren't very good and let to much voltage through, or are surges causing a problem or something like that? Someone doesn't necessarily have to have experience with this unit to say whether or not faulty / poor quality voltage regulators could cause damage to the circuit it is being used to power. Anyone familiar with how these types of units work could probably comment on what inside of them could be cheap and cause risk.

If it's something like voltage regulators, then the question becomes would an additional 7805 5v voltage regulator between the power and my main circuitry be enough to take care of any potential over voltage? What would happen if the unit sent 110 volts down to a 7805, would the 7805 fail and leak additional voltage into the circuit or would it just burn out but keep the circuit safe? Would adding fuses help?

Lakes:
An alternative would be a PICO PSU
http://www.ebay.co.uk/itm/Pico-PSU-12V-120W-DC-DC-MINI-ITX-ATX-Power-Supply-PC-/160860474433?pt=PCA_UPS&hash=item2574080c41

Thanks for the suggestion, but looks like that is a DC-DC power supply. I would still need an AC-DC transformer on top of that and would prefer it to be all one unit. That Pico PSU looks like it's designed for Carputers and projects of that type.

I've got a couple of other old laptop power supply bricks laying around, but most of them are upwards of 19v 4A+, way more than I need. I might would use one of them with some regulators I'm just worried regulators of that size to knock that down to a usable 3.3v or 5v in my main circuitry would be putting out quite a bit of heat.

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Not sure what your reference to lamp is, the only thing I know for lamp is the acronym linux apache mysql perl.

Lamp as in light bulb. Wiring lamps of the proper voltage rating that will load the supply to close to their rated current capacity and monitoring it's performance for some period of time (say 100hr burn-in) is one way to gain confidence that a specific power supply you have will function reliably in your project.

I've bought many many 'used' power modules from thrift stores over the years, often for only a dollar or two, and of both linear regulated and more modern switching regulator types and never have had a problem with long term reliability. I would never pay retail for a low voltage DC power supply in the 50 watt range or less, as I've just found it too easy to find functional ones at thrift stores for pennies on the dollar. It's not a way a commercial company would procure parts for products for sure, but hobbyist have more choices and flexibility. I buy lots of electronic parts and modules (like power modules) not because I may have an immediate need for them, but rather because they may be of a very attractive price and very useful function for future projects.

I offer this general information and opinions mostly because I feel you will have little luck getting any direct user first hand experience and feedback about that specific power supply. Maybe you could write to SparkFun, explain your concern about reliability and ask how many complaints or returns they have had on that specific model?

Lefty