Jo22 wrote on 2023-07-24, 23:14:

Is that really true? I'd love to see some sources, if there are any. Because, the global picture looks different to me. Electro […]
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wiretap wrote on 2023-07-23, 20:12:

shevalier wrote on 2023-07-23, 15:40:

No, boards (at the time of their relevance) with previously exploded capacitors have long been recycled.
Now it's the turn of the lucky survivors.

Manufacturing defect in a capacitor or another fault causing it blow. I still run hundreds of boards at work with tantalum capacitors in the 30-40yr old range that have yet to blow one. They're definitely an extremely reliable design. I don't hesitate when replacing them with the same thing on my vintage computing parts because I know they'll make it another several decades. Manufacturing now is leaps and bounds better for those parts than it was in the 70's/80's/90's. The reject rates on the assembly line is almost 10 fold lower.

Is that really true? I'd love to see some sources, if there are any.
Because, the global picture looks different to me.
Electronics are getting more and more cheap, which to me makes it hard to believe in any kind of progress.
The electronics parts my father had bought in the 70s do have golden legs, I remember.
They're from known-good sources too, since Chinese suppliers didn't exist yet.
The ICs he had (has) do have ceramic packaging and are made using TTL and NMOS process, both which have more "oomph" than CMOS designs.
They're all 5v tolerant, as well. And produced in a bigger manufacturing process, meaning they're more though.

This is my experience exactly.

There cheap tantalums, cheap MLCCs and there are expensive MLCC and tantalums. If you buy a modern, good brand tantalum, it will hold for decades. And with the better brands they won't fail short either.

It is my experience in manufacturing, that generally speaking, the process is the same when it comes to manufacturing the consumer vs military/aero grade parts. It's just the more expensive part sold is tested to more extreme conditions, and produced on the best equipment to get the best yield. No one that sells stuff to get the mil/aero contracts wants to be known as the company whose parts go boom. Finally, they come with some level of guarantee, so this specialty item sold probably has extra mark up to cover any fault that might occur. It's this extra testing, time, and specialty that really drives the prices up.

You don't need to buy the most expensive part to get something that lasts. Just buy from a company who is reputable, and you are basically getting the same thing. Of course buy the right part for the thing you are replacing...

I'd figure that 80s tants that had this problem, were not expected to these to have been run, sit for decades, and then powered on out of curiosity. However, I'd suspect the manufacturers have paid attention to this fault, especially since mil/aero has had similar equipment in service for a long time dating from then too, and probably keep a stockpile of old stuff and have gone through replacements themselves. Age and servicability is a thing. They've already seen the issue and done something about it. As tants are still made, there is a good reason why -- that means they are not unreliable.

the3dfxdude wrote on 2023-07-25, 16:08:

I'd figure that 80s tants that had this problem, were not expected to these to have been run, sit for decades, and then powered on out of curiosity. However, I'd suspect the manufacturers have paid attention to this fault, especially since mil/aero has had similar equipment in service for a long time dating from then too, and probably keep a stockpile of old stuff and have gone through replacements themselves. Age and servicability is a thing. They've already seen the issue and done something about it. As tants are still made, there is a good reason why -- that means they are not unreliable.

Seems MLCCs can have sideeffects, too. They are usually less consistent over temperature ranges, as tantalums are, also they can produce audible noise, as they have a piezoelectric effect. This doesn't happen to tantalums either. Depends on the frequency of the AC component though. There is no such thing as "the perfect capacitor". It all depends on your requirements. But as said before: modern tantalums from a well known brand should last many decades and not go boom, and might be ideal if you want that retro look. If you can get MLCCs cheaper and don't care for "the looks" they might be sufficient.

The change in reliability came with the switch from Ta2O5 to f-tech. There are dozens of papers on it. F-tech eliminates crystalline inclusion flaws that caused failures because of manufacturing defects and chemical interaction.