Topic: ZTEX USB-FPGA Modules 1.15x and 1.15y: 215 and 860 MH/s FPGA Boards - page 44. (Read 182443 times)

"Close only counts in horseshoes and hand grenades" - ancient American proverb

There are valid points on both sides of this argument, which at this point have been hashed, rehashed, and re-rehashed again.  Nobody here is clearly 'in the right' or 'in the wrong', nor trying to scam anyone, we can be better than continuing to pass blame or throw slander.

ztex, if I were you I'd replace the first board for two reasons:

1. You're selling to novices who aren't going to test their PS accurately, they just want moar hashes naow.  If Gusti's PS was rated within the specs but the board failed due to overcurrent/overvoltage anyway, well, only experts would know better.  If you do not supply or direct purchase of a verified PS, and instead give only recommendations, you must honor failures when the used device is labeled/rated within those specifications, regardless of whether or not it actually is.

2. Credibility and clout.  Novices aren't going to buy your board if they feel they won't be able to power it properly and come to the conclusion there is zero recourse for them if something should go terribly wrong.  It's a hit, to be sure, but a good gesture here would lend much to trust in your product.


I would not, however, replace the second board pretty much for the reason you stated.  Still gusti may not yet have known the PS was an issue, however you can't really be held responsible for that oversight twice.  This is like buying a car, accidentally filling the tank with water that was labeled 'petrol', doing the same to a second car when the first stops running, and then blaming BMW for faulty cars.  You would know better to expect sympathy in that situation, and this is no different.

You're both right, you're both wrong, and compromise is the best resolution.

Not so obvious, I'm only believing in your diagnostic. But in your arrogance, you will not admit that you could prevent this from the design, with the addition of a zener diode, as enigma suggested in this post. Other manufacturers are also protecting their products from over and reverse voltage, so proper protection is not utopian.

 

I consider myself to be way above average when it comes to electronics, but no where near the level of ztex and enigma. I could've done the same thing as you did in your situation - I actually did hook up another small consumer electronics device where the manufacturer psu had died upon me to a psu I found laying around just a few weeks ago after having just verified polarity and rated output voltage*.

It's possible I thus could've fried one of these boards as well, being that careless, and not immediately considering the difference between switching and transformer (which is where my mostly DC/digital knowledge of electronics ends).

However, there's no way I would blame ztex. I'm sorry, but consumer electronics are never protected against over voltage. There's no reason to assume these would be either, thus there is truly no responsibility on his part.

I do thank you for bringing up the subject, which has led to additional information and cautions now being available for those (which might include me) that buy boards from ztex or anyone else in the future.


*) edit: I also measured the voltage with my non-cheap multimeter, although it does not show max/min as most don't

12V is save.


But this unit obviously has a peak voltage of larger than 18V. I'm not responsible for the label of Gusties power supply.

Either it is regulated or it is unregulated. In inaccurate 12V supply with a tolerance of -65%/+33% works.

Was it bad luck that you destroyed the second board in the same way as the first one instead of asking me what went wrong?

Thanks and agreed, maybe a bit much to call ztex a scammer. I apologize to the community for my wrongly choosen words.
I only wish ztex to take his part of responsability for this problem.

  I'm sorry but I have to agree with Gusti here. Atleast in his situation the bare facts are he was told 12v is safe. His power supply unit states output is 12v. Though, the scammer tag is really a bit much, m8. And you would have gotten a much more positive community response without it.

  The fact that I would grab that PS out of my box and think to myself, 'man, this huge ass transformer is probably too much juice for this little board', has absolutly zero bering on the expectations one should have for their customers.

  The ideal disclaimer on the PSU purchase should read that they are intended for use with high precision 12v atx type PSU's. The use of aftermarket transformer style PSU's should be of the type used for very small devices that require less than 12v 600ma. If you are unsure a PSU is safe to use, DO NOT plug it in and please submit its exact specs to us to ensure it is safe to use. Thank you for using our products. Ztex


  Cheers

Thanks for your insights, but remember the fact that I did not plugged the boards to 380v or did I exposure them to heat or something like that. I only had the bad luck to use a power supply with (maybe) slightly unregulated output. This is what ztex says, and as I'm not an engineer, I give credit to him.

As ztex is not supplying an original PS, I believe this will not be the last case when a customer will use a power supply that will be out of specifications. Customers must be warned to be careful with this. And I still believe manufacturer need to take some responsibility and refunding the failed boards.

 

This is the last time I'm personally going to get involved in this discussion..  It's over in my mind and ztex stands as "NOT a scammer", to me anyway..


The specifications state that these boards may be operated from 4.5 to 16V.  WHAT MORE OF A WARNING LABEL DO YOU NEED?

Danger, if exposed to a bath tub, ztex boards may no longer function.

Caution, if exposed to a lightning strike, ztex boards may no longer function.

Warning, ztex boards were not designed for use at temperatures like those found at the center of the sun.  Operation inside of the sun is not guaranteed.

Notice, do not take ztex boards swimming with you.




You've really gotten to the point of hysteria with this whole topic.  NONE OF THE PRODUCTS YOU OWN are protected against over voltage - Literally NONE of them.  Hook your 30, 40, 50 thousand dollar vehicle up to 110V and watch what happens (it's pretty awesome, by the way).  Hook your cisco/linksys/d-link product up to reverse voltage or double voltage and see what happens.

ztex very clearly states that the boards operate from 4.5 to 16V.  I don't see how the specifications could possibly be any more clear.  It's like a vehicle tire - they have a speed rating - S, for instance means 112MPH.  There is no further warning.  The speed rating tells you that it's safe to operate the tire continuously at 112MPH.  At 113MPH, the tire may explode, but there isn't a bright orange warning label on the side of the tire..  It's been stated, and doesn't need to be stated again..

I'm glad ztex added a wiki entry about power supplies, but I will defend his old specifications - they were plenty clear.  He simply can't be responsible for you providing power far outside the specification - which from the burnt chips, you clearly did.

If you'd like to PM me, I'll even let you send me the power supply in question (3com) and I'll tell you beyond doubt whether it hurt the ztex board or something else did.  I have hundreds of thousands of dollars worth of test equipment at my disposal, and I will be able to see if that supply is dangerous to the ztex power supply or not.  Beyond that offer though, I'm ignoring this thread.

Enigma.

Not enough, let me help with a warning you should put in writing, if you really care about your customer's money.

"Dear Customer : these boards are not designed with overvoltage protection, and will burn themselves if you happen to choose a power supply that is not exactly regulated. Please take this into account, and choose only switching PC-type power supplies, do an output measure reading before using it, or use at your own risk".




 

Not "any" overvoltage, +33% over 12 V is pretty good headroom.

People like this are the reason that coffee cups have a "WARNING: HOT" label on them.

Herewith I warn: Boards may be damaged, if they are operated out of specifications.

Excuse me, but not FUD, only facts. The design has no protection (fact), and will burn with any overvoltage (fact).
Customers must be warned, as I was not.

No, they aren't. Those posts start looking like FUD.
I understand that you are upset because of your loss, but we see that other people agree about good enough board design.

I'd read Enigma's post. You are not responsible if PSU delivers more than expected, but you MUST warn your customers about the fry situation. Specially if you choose the design way of not adding an additional zener diode for further protection.

Your boards are too dangerous for average customer use.

But I mentioned that the valid voltage range is 4.5V to 16V.

I'm not responsible if your PSU delivers more than stated on the label.


Please read the post from Enigma81: https://bitcointalksearch.org/topic/m.639147

That's right, anyway you did not mentioned "switching" when I asked you first. You also did not mention to be specially careful, to do prior measures or have the power supply being tested by a knowledge party, because boards have no protection.

You need to specify all of the above, or more customers will have losses.



 

I wrote "switching power supplies are stabilized".


If you omit "switching" you can find it ...

Yes, it has voltage selection. I think it was using different windings of the transformer. Nowhere near the stated voltages and enormous ripple.