Very Disapointing New Bench Power Supply!

https://www.amazon.com/Precisi...=dc+power+supply   

Fairly good reviews..i wonder if you got a bad one? This one 10amp

You have probably checked, but could there be a fuse or breaker somewhere? But I agree the instructions seem pretty demanding for a piece of test equipment.

I bought the 10A model, and I've started it up with a heavy load plenty of times.

As I understand it, the warning to have your load disconnected when these cheap DC power supplies are turned on is because their output isn't correctly regulated until all of the circuitry is up and running (which happens in a fraction of second). Unfortunately, in those few initial milliseconds you often get much more voltage than you might want and can fry something that's connected.  Same thing when the mains power is disconnected.  I've never understood that the warning was to protect the PS - sounds like you might just have a bad one.  The quality of those are very...modest, shall we say.  More expensive bench supplies have the additional circuitry to prevent this sort of problem.

I agree, the startup voltage isn't, shall we say, consistent.   I was testing it's load capability with big power resistors, so I didn't worry about what the voltage was at startup, the resistors didn't seem to mind.

I would say you have a defective unit.  I have 3 of these in the workshop, and 6 more in the field operating trains on the ceiling layout at a business.  They start with the load applied all the time.  Every day every way.

In a follow up answer, the left set of control knobs is for current limit, if they are turned counterclockwise the unit will not output any voltage.  Turn the right current limit clockwise, then turn the voltage clockwise.  Do you now have an output?

I use USA Made Astron DC Power Supplies on my workbench.

http://www.astroncorp.com/

The taste of poor quality lingers long after the euphoria of a low price.

aussteve posted:

The taste of poor quality lingers long after the euphoria of a low price.

Sure wish I had said that!  My euphoria has long vanished.

choochoopaul posted:

In a follow up answer, the left set of control knobs is for current limit, if they are turned counterclockwise the unit will not output any voltage.  Turn the right current limit clockwise, then turn the voltage clockwise.  Do you now have an output?

Yes Paul I am all over that. Both current knobs are fully clockwise. I was ready for this suggestion because I knew someone would post it. Also the C.V. Led on the right side is lit up, which means the voltage controls are active, not the current controls. No joy, but thanks for the suggestion.

choochoopaul posted:

I would say you have a defective unit.  I have 3 of these in the workshop, and 6 more in the field operating trains on the ceiling layout at a business.  They start with the load applied all the time.  Every day every way.

Is it the 10 amp model, or the 5 amp like the one I pictured? From what others are saying the 10 amp unit sounds quite robust, but this 5 amp unit is junk if you can destroy it by simply hooking up a load before switching it on. That's garbage and I would never have bought the thing if I had known that, euphoria or not!  And yes I did check the fuse; it's fine.

My advice to others stands; stay as far away from these crappy 5 amp units as possible!

Rod

Well, I'd be surprised if the 10A unit was a lot different in design than the 5A unit, but I am temped to take it apart and look around inside.  I principally got mine for occasions where I needed more than the 2A that my normal bench supplies give me.  The most use it got was when I was doing load testing on it to see if it would actually deliver at least 8-9 amps.  It makes a dandy heater with all the big resistors sitting on the bench.

The seller has just come back with an offer to give me a 50% refund and I get it fixed locally. Yeah, right. Since it has never worked properly since I took it out of the box, I don't think so!

Rod

Rod, if you paid by credit card you may have some recourse there.  I've disputed the rare failure and if the seller didn't set me whole, my credit union did.  Good luck.

My experience on eBay with these guys is you have to press the point.  Since you probably used PayPal, you have way more leverage than they do.  I've had several Chinese firms send me totally incorrect items recently.  They would initially try to get me to accept partial credit, which I promptly refused.  Then I would get the refund and they asked if I would send the items back.  I replied that I certainly would as soon as I got a paid return shipping label.  They get to send the stuff from China for peanuts, but it would cost me a ton to ship it back!  At that point they simply close the books.

gunrunnerjohn posted:

Well, I'd be surprised if the 10A unit was a lot different in design than the 5A unit, but I am temped to take it apart and look around inside.  

Ignorance may be bliss - some of the teardowns I've seen online for these types of PSUs make one pretty confident they are not U/L listed.

But...but...they say "CE" on them.  That means they're safe, right? 

gunrunnerjohn posted:

My experience on eBay with these guys is you have to press the point.  Since you probably used PayPal, you have way more leverage than they do.  I've had several Chinese firms send me totally incorrect items recently.  They would initially try to get me to accept partial credit, which I promptly refused.  Then I would get the refund and they asked if I would send the items back.  I replied that I certainly would as soon as I got a paid return shipping label.  They get to send the stuff from China for peanuts, but it would cost me a ton to ship it back!  At that point they simply close the books.

grj; It was purchased thru ebay and paid for thru Paypal. So yes I think ultimately I have pretty good chances on a happy solution. I have told the seller (located in NJ) that I don't want a replacement because I have no faith that it will work. But I really don't want it knowing that there is the stipulation that the psu has to be powered up before connecting the load. That's just plain stupid.

Good point on the shipping label. I will demand a prepaid RMA label before I ship.

This beat goes on. Rod

Casey Jones2 posted:

I use USA Made Astron DC Power Supplies on my workbench.

http://www.astroncorp.com/

Those look nice but they also look more expensive. I'm sure you get what you pay for. Thanks.

Sean

I'm not unhappy with mine for the price.  It delivers a pretty clean looking 10A of DC and the meters are fairly accurate, about 2% from my bench Fluke meter.  For the intended use, it's just fine.  It doesn't get used enough to spend a lot of money on it.

Now they have come back with an offer to refund me 80%. That's not too bad but then I still have a useless piece of junk on my hands. There is not likely any way you could find a circuit diagram for it so the chances of being able to fix it are slim to none I figure. And even if I could get it fixed, it will still fritz again as soon as I forget the stupid hookup sequence limitation; which is pretty much guaranteed to happen at some point. I am going to hold out for a full refund and they pay shipping if they want the hulk returned.

Rod

What would they charge for an upgrade/exchange for the 10a model perhaps?

Rod Stewart posted:

Now they have come back with an offer to refund me 80%. That's not too bad but then I still have a useless piece of junk on my hands. There is not likely any way you could find a circuit diagram for it so the chances of being able to fix it are slim to none I figure. And even if I could get it fixed, it will still fritz again as soon as I forget the stupid hookup sequence limitation; which is pretty much guaranteed to happen at some point. I am going to hold out for a full refund and they pay shipping if they want the hulk returned.

Rod

80% refund for something that never worked?  That is odd. I wouldn't think you did anything wrong, and I doubt the issue was that you had a load on it when you turned it on. My bet is that it was just defective. Hold out for full refund and they pay return shipping.

Sean007 posted:

Casey Jones2 posted:

I use USA Made Astron DC Power Supplies on my workbench.

http://www.astroncorp.com/

Those look nice but they also look more expensive. I'm sure you get what you pay for. Thanks.

Sean

Hey looks very nice. And analog meters; how quaint is that?

Rod

Rod, I'd simply put it in eBay's hands and stop dealing directly with the company.  For defective products, they normally are quick to simply refund your money.

How about this one? Any ideas/predictions on its quality?

https://www.banggood.com/LONG-...ehouse=CN#customerQA

SIRT posted:

Not sure why anyone would need a Power Supply today

People who work on and repair electronic hardware use power supplies.

Rod Stewart posted:

On a recent topic there was information on an inexpensive 0-30 VDC 5 amp bench power supply. Price was right at $42.99 plus 9.99 shipping, even up here to Canada! So I jumped in and bought one to replace my small 1 amp bench supply.

Well it arrived safely and looks great. Picture below. I read the manual, then fired it up for a test. On page 1 of the manual there is a dire warning: "Do not connect any load to the power supply before it's turned on. Likewise make sure to disconnect the load before shutting down the power supply." Well guess what? I must have botched it up and connected the test load first, because there is absolutely no voltage output at all. The displays light up, but no amount of voltage knob turning produces anything other than 0.00 volts. Whoopy-ding!

Even if you got this right the first time or two I can virtually guarantee that after you haven't used it for a couple of weeks or a month, bingo, you will get the sequence wrong and poof; instant paperweight! What kind of a stupid design is this? I am checking to see if the seller will exchange it,  or hopefully I can return it for a refund. Because I can see the same thing happening again.

My advice? Stay as far away as you can from these!

Rod

I once had a digital camera with just such a warning to never open the memory card door when the camera is powered up.  You guessed it !  Except I did not intentionally open it, my hand just slid over the latch and it springs open.  Well after having it repaired I took an Xacto knife and whittled the latch button so that it was rather difficult to open even when trying to do so. It never opened by accident again.  Print yourself a nice warning sticker to place over or near the power button.  Take the 80% and buy the parts to repair it.  Good Luck.     j          

i've been using this Lambda supply for decades... pick up a used one and avoid the new crap that is for sale.  you can find them in a number of different output ratings.

  I had a 50a Astron, but sold it because I couldn't lift it anymore. It weighed more than a Snap-on roll-away 50a car battery charger.   Ham radio folk seem to love them. Great piece. Very stable output, high quality. If I had a need for "clean" I wouldn hesitate to own another made by Astron.... a little smaller of one anyhow    But as is I’m golden with bridge rectifiers for DC from a few old school AC train transformers.

As long as you are within the advertised return policy you are OK.  Make sure you have some documentation that they are not honoring the return policy.  Next step is to put it in the hands of paypal.  I always try to pay using a credit card.  Then all  you have to do is hit the dispute button on the banks web site.  The bank will call you.  You tell them what happened.  The bank says they will investigate and let you know in a few days.  My experience is the money is back in my account within hours.

I'm sure Rod has taken care of this problem by now, as this thread started 2 1/2 years ago. Roy is asking about a different PS. I looked at that one, but bought one like Rod pictured, and have had no problem in 2 years of use.

overlandflyer posted:

i've been using this Lambda supply for decades... pick up a used one and avoid the new crap that is for sale.  you can find them in a number of different output ratings.

Wow, Does this bring back memories! I worked in specials Engineering at Lambda  for a couple of years.

I have some real antiques.  The first one I built over 40 years ago, other than replacing the capacitors a few years ago, it's still going strong.  The other one I bought at a yard sale for $5, also many years ago.  It also got a couple caps replaced and has worked ever since.  They get used all the time, and are normally all I need.

FWIW, I have one of the 10A supplies just like Rod shows, it's in my back room shop, but it doesn't get used that much.

Power supplies are like trains; you can never have too many! 

I was surprised to see this thread active again!

Rod

Rod Stewart posted:

On a recent topic there was information on an inexpensive 0-30 VDC 5 amp bench power supply. Price was right at $42.99 plus 9.99 shipping, even up here to Canada! So I jumped in and bought one to replace my small 1 amp bench supply.

Well it arrived safely and looks great. Picture below. I read the manual, then fired it up for a test. On page 1 of the manual there is a dire warning: "Do not connect any load to the power supply before it's turned on. Likewise make sure to disconnect the load before shutting down the power supply." Well guess what? I must have botched it up and connected the test load first, because there is absolutely no voltage output at all. The displays light up, but no amount of voltage knob turning produces anything other than 0.00 volts. Whoopy-ding!

Even if you got this right the first time or two I can virtually guarantee that after you haven't used it for a couple of weeks or a month, bingo, you will get the sequence wrong and poof; instant paperweight! What kind of a stupid design is this? I am checking to see if the seller will exchange it,  or hopefully I can return it for a refund. Because I can see the same thing happening again.

My advice? Stay as far away as you can from these!

Rod

We purchased the same ones for my work.  They are OK for the most part but can be flaky.  Sometimes the voltage goes to zero for no reason, can be a real pain when I'm in the middle of testing something.  Usually a cycling of the power restores everything.  Make sure the current setting isn't to low.

The one on the right has been bullet proof.  Sadly you can’t get that make anymore 

Chris, appreciate the ideas, but this all started well over 2 years ago. I dont recall all the gory details now, but I tried everything at the time. It is just a faded bad memory at this point. 

Rod

Rod, we like to bring stuff back from the dead, we were hoping to do that with your power supply!

In addition to playing with and rebuilding/modifying toy trains, I also repair and modify antique car radios. That's why I would like a power supply that can do 6.3 and 12.6 volts up to 10 amps. The power supplies in this thread seem ideal except for the complaints about reliability. The Lambda one looks nice but seems to top out around 2 amps, which is not enough for my uses.

FWIW, my identical supply has been fine as far as reliability goes.  They do have the same comment about no load at startup, but they make a statement that it may get a voltage spike when you power it up.  I haven't seen that issue surface, but I am careful in connecting it to anything critical.