I knew I’d find that data sheet if I just quit looking for it….. The 250 watt version of the 020/021.
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And those ones I posted earlier are the genuine article. Received as free samples from Onsemi
So I have to say, why risk buying from sources outside authorized distribution channels?
Total failures are easy. The real headaches come from parts that work, but not well.
Total failures are easy. The real headaches come from parts that work, but not well.
Real LM317 received from Mouser today.
"Total failures are easy. The real headaches come from parts that work, but not well."
Agree,two of fake boards are functional but burned immediately when output shorted.
On the left is the original,on the right is the fake.
"Total failures are easy. The real headaches come from parts that work, but not well."
Agree,two of fake boards are functional but burned immediately when output shorted.
On the left is the original,on the right is the fake.
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Then there is regulation and noise. That can cause whatever they are powering to operate poorly compared to the performance they should give.
Here electronic component buisness is little weird compared to other part of the globe (I assume so). 4-5 yrs ago i bought genuine 317/337(ST & ONSEMI 'dual & single gauge') from an authorised dealer at a very down to earth price, whereas then the price was tenfold+ at big online vendors like RS & Mouser. I believe this is applicable only for industry grade parts, not any exotic type which is barely available here at local distributors. Anyway, then i found some NATIONAL made LM337T. The strange thing is their physical dimensions is identical to datasheet drawing except the marking which i found little different then the original NATSEMI marking of LM337T. I believe these are early genaration Natsemi adjustable regulators, relabeled & sold.
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Hi xenofonn,
Cosmetics are getting better on fakes. Look up the data sheet and check to make certain the markings agree. Measurements would be the next check.
If they were listed as new manufacture on a discontinued part - they are fake. If the price was below what it should be .... probably fake. It just isn't worth buying stuff you can't be sure of.
Cosmetics are getting better on fakes. Look up the data sheet and check to make certain the markings agree. Measurements would be the next check.
If they were listed as new manufacture on a discontinued part - they are fake. If the price was below what it should be .... probably fake. It just isn't worth buying stuff you can't be sure of.
I agree, the finish and feel are way off.
You risk damaging the circuit, they are that bad.
Try and return them.
You risk damaging the circuit, they are that bad.
Try and return them.
I would still try to make some measurements as anatech suggested. The problem with a visual inspection is that we may be condemning a slightly off genuine batch as fake and a well made fake as genuine while in reality, things are reversed.
However, having said that, I would suspect anything from non-authorized resellers (think Avnet, Digikey and the likes) as fake unitil proven otherwise.
However, having said that, I would suspect anything from non-authorized resellers (think Avnet, Digikey and the likes) as fake unitil proven otherwise.