The power supply of my mckinnie pre-preamp died, so I bought a small 317/337 PS kit to replace it.
The negative leg didn't work, no biggy, I ordered a handful of LM337 from Aliexpress. All bad.
I ordered another small batch from eBay, Germany. All bad. It turned out they're the same items as Ali.
The prob appears to be some kind of a short between Vout and Adjust, so Vout is always ¦Vin¦ - 2V, regardless of the setting.
Out of curiosity, I ordered another batch from eBay China, but they've not arrived yet. We'll see if this is epidemic level.
Finally, I've got some NOS Motorola 337 from eBay France, and all is well.
I don't usually have problems with parts from Ali, but stay away from the 337 for now,
The negative leg didn't work, no biggy, I ordered a handful of LM337 from Aliexpress. All bad.
I ordered another small batch from eBay, Germany. All bad. It turned out they're the same items as Ali.
The prob appears to be some kind of a short between Vout and Adjust, so Vout is always ¦Vin¦ - 2V, regardless of the setting.
Out of curiosity, I ordered another batch from eBay China, but they've not arrived yet. We'll see if this is epidemic level.
Finally, I've got some NOS Motorola 337 from eBay France, and all is well.
I don't usually have problems with parts from Ali, but stay away from the 337 for now,
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So, you order parts from dubious places instead of mouser, digikey and the rest of verified suppliers, and get surprised that they don't work 😅
Take a look inside your car: a lot of the parts are from "dubious places". And you're betting your life on them! 🙂
examples? Not aware of Automotive buyers turning to Aliexpress?
I worked in semiconductors (and electronic modules prior to that) supplying the auto industry. The reason a lot of mil spec has fallen away is because the auto industry pushed semiconductor quality to what it is today. There are no parts of dubious provenance in modern automobiles.
Have you connected the lead of LM337 correctly?
You know, it is not the same pinout as the LM317.
See the datasheet.
You know, it is not the same pinout as the LM317.
See the datasheet.
I'm talking about the guys who make the parts, not those who sell them. And it's a praise, not than a criticism.
Re.: pinout: yes, I'm aware. From the pics above, you can see it's the exact same test rig I used.
Btw, the left section of my rig is for the 317; and the ones I have all test good, no worries on that front.
Maybe your lm337 is lm317 remarked one ? Test with dmm internal diodes and compare with working lm317.
Automotive parts aren’t made in dubious places either. Every single part of the supply chain has strict quality controls applied no matter where they’re made.
Thx Mark.
I usually do my shopping at Mouser. But I do forget things, or change my mind after an order is placed, so Ali or eBay come in handy for small orders. like a few bucks, so the risk is contained.
The intent of this post is to make people aware of some possibly major issues since the faulty items come from 3 different vendors. One of these has been very upfront stating that "this is not a problem, we have sold a lot of these products, other customers can use it normally". I assume the "other customers" suffer in silence.
I don’t want to pile on, but let this be a warning not to buy semiconductors from random sellers on eBay, Aliexpress, Amazon. At least nothing caught fire or was damaged on your circuit board.
Stick to distributors first, and to sellers that have been confirmed as reliable sources for the specific products they are selling. There are good sellers out there, but the other 98% are selling counterfeits and defective rejects.
Stick to distributors first, and to sellers that have been confirmed as reliable sources for the specific products they are selling. There are good sellers out there, but the other 98% are selling counterfeits and defective rejects.
I beg to differ.
If I may step out of my own topic just for a bit.
It depends on which car. My experiences with 3 different VW, from new:
- VW #1: door knob coming off, MTFB: 1 week
- VW #2: coolant hose leaking, MTFB: 2 months
- VW #3: auto transmission total failure, MTFB: 2 years + 1 month. Because it was fresh out of warranty, VW generously offered to take over half of the repair cost: 6K
Alixpress & ebay is full of counterfeit components & it is not unknown to us. Those regs are inexpensive so why take risk?
Fyi
I have had a couple of defective TI lm237kc recently that were bought from mouser. Different date codes Wondering if TI would want to do failure analysis.
Never had one bad ST Lm217t-dg so far, also bought from mouser.
I have had a couple of defective TI lm237kc recently that were bought from mouser. Different date codes Wondering if TI would want to do failure analysis.
Never had one bad ST Lm217t-dg so far, also bought from mouser.
Remember that "Quality" often doesn't mean that nothing ever breaks, but it does mean that you know where your components come from and who made them - big difference.