Author Topic: Digi-Key Sold Me 7 Year Old Capacitors  (Read 4706 times)

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Offline Brumby

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #25 on: August 30, 2019, 03:31:41 am »
Well Brumby,

All I can add is that I'm almost positive that the Tenma isolation transformer would have blown its 3 Amp fuse if the Tektronix power supply demanded more current than 3A at 120 VAC.

...and no loads were applied to the Tektronix SMPT while I was ramping up the AC voltage on my bench outside of the oscilloscope. None of the PCB's were connected or fed by the main ribbon cable connector, it was disconnected.

Oops, maybe I shouldn't have left out this fact :)

You aren't understanding what I've said.

The numbers I quoted were MADE UP - purely to illustrate a point.  I have absolutely NO idea what the numbers will actually be in your setup.  Those numbers WILL BE DIFFERENT.

However, while the numbers will be different, the principles still apply.

Using my made up numbers to justify your setup is plain silly - and just a little bit worrying.
 

Offline SmokyTopic starter

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #26 on: August 30, 2019, 04:43:04 am »
Don't you do any worrying Brumby!

I just meant to say that I didn't see any unusual amperage draw on the isolation transformer (I can switch between amps and volts on the fly).

The SMPS outputs are regulated, so if I'm not mistaken, a load on them isn't required during powering on.

I just felt I was playing it safe by slowly bringing up the SMPS with the isolation transformer after the "new-old" capacitors were installed.

I'll remember to "reform" large electrolytic capacitors before I install them in a SMPS repair next time and I will not slowly bring up the input AC voltage during the restart.

The TDS420 is running very well, and I imagine it will, well into the future :)




« Last Edit: August 30, 2019, 08:02:14 am by Smoky »
 

Offline Brumby

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #27 on: August 30, 2019, 12:59:29 pm »
Ah ... OK then.   :-+
 

Offline SmokyTopic starter

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #28 on: August 31, 2019, 10:00:15 pm »
I just received a follow-up response from Digi-Key.

They refunded the cost of the five LGX capacitors from my previous order.

I appreciate that, but initially, I requested of them just to send me two "newer" capacitors out of the five.

Anyway, they also said that I can request capacitors not to be older beyond a certain date by using the "Order Note" comment section when placing an online order.

From the responses I've received on EEVblog.com, there wasn't much to worry about concerning the 2012 capacitors, so I have no problem either.

All is good and I do very much appreciate the help from the EEVblog.com community.

You didn't have to go that far Digi-Key, a small credit towards my next order would have been just fine, but thank you too!
 
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Offline Brumby

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #29 on: September 01, 2019, 01:14:42 am »
I am not surprised by Digi-Key's response.

Companies that care about their reputation will tend to address issues with a solution that only requires their attention once and with minimal effort.  Exceeding a customer's expectations - especially on such a small matter - is the quickest and easiest way.

Besides, they don't know if you are developing a project that could turn into a $10k order every month for a few years.....
 
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Offline Bud

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #30 on: September 01, 2019, 02:20:18 am »
I recently got a bunch of jelly bean logic ICs from Digikey in PDIP package, all of them of Texas Instruments brand with date codes 2018÷2019. The bizarre thing was all of them had leads blackened as if they oxidized. It was unusual for such freshly made ICs to have that. The even more weird thing was the leads were only dark on the outside of the leads, the leads sides facing each other  looked normal. They came in tubes. Search for TI PDIP leads finish did not produce any recent hits. I did not speak with Digikey on that, just used an eraser to clean the leads before soldering as i wanted to go ahead with my project.
Facebook-free life and Rigol-free shack.
 

Offline mcovington

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #31 on: October 02, 2019, 12:09:50 am »
One detail: Nichicon is one of the most respected brands of capacitors, as I understand it.  Maybe theirs last longer.

I'm currently trying to decide whether some 15- to 30-year old capacitors in my stock should be tossed...
 

Offline alank2

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #32 on: October 02, 2019, 02:21:07 am »
I really like Digikey's search engine, but their customer service disappoints me nearly 90% of the time I bother to contact them.  They almost always want to tell you it is your fault.  They love to tell you that if you didn't put it in the order notes that it is your fault.  Order a part and get a date stamp that is fine  Order two more and get one that has an older date stamp with errata on it.  Call them and they will say "you didn't ask for the newer one, it is your fault".

Mouser on the other hand has always had a good attitude with me and is quick to solve problems.
 

Offline chickenHeadKnob

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Re: Digi-Key Sold Me 7 Year Old Capacitors
« Reply #33 on: October 02, 2019, 10:04:02 pm »
I recently got a bunch of jelly bean logic ICs from Digikey in PDIP package, all of them of Texas Instruments brand with date codes 2018÷2019. The bizarre thing was all of them had leads blackened as if they oxidized. It was unusual for such freshly made ICs to have that. The even more weird thing was the leads were only dark on the outside of the leads, the leads sides facing each other  looked normal. They came in tubes. Search for TI PDIP leads finish did not produce any recent hits. I did not speak with Digikey on that, just used an eraser to clean the leads before soldering as i wanted to go ahead with my project.

There is a situation that can occur with tin plating I have heard of but not seen myself: micro motion  fretting corrosion, small wear movements of say the pin legs against the tube leave a black surface. That would explain why only the outside of the pins show it. Was any tarnish on a surface that wasn't in contact with another surface?

Samtec pdf on the phenomena: http://suddendocs.samtec.com/productspecs/fretting-corrosion.pdf
 


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