Bad cap topologies

So how does the Chinese company Lifetime stay in business?

Many Chinese component manufacturers don't sell to outside of China. The companies that buy from them build a production run of a product and then stop. They then move one to the next product. By the time they show up on your shelf, it may be 3-6 months since they were produced, and several models ago.

The manufacturer simply does not care, they don't take warranty returns. If the unit price of a product is $50 and 1% are expected to fail, they sell the for $48 (in reality they price them at $52 and sell them for $50). It's up to the importer in your country to deal with returns.

In the case of large companies, they don't bother. A returned item is replaced with a new (and probably later) one, and the old one gets thrown out or recycled.

Small retailers do the same thing via their distributer or just trash them depending upon the contract they have.

None of the units ever make it back to China, except in containers of recycled goods for dumping.

This is nothing new, about 25 years ago I was very friendly with the number one importer of "220" or "grey" goods on the east coast of the US. He would take defective stuff back for repair, but could never keep a tech at what he could afford to pay them. In the end the stuff just ended up in the trash and the prices were raised enough to cover the losses.

I also read news stories in the past where major US retailers were keeping track of people who returned goods and if you returned too many, they would not let you return any more.

One US manufacturer of radios has a 30 day return for refund policy, but won't sell you another radio if you return one.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com  N3OWJ/4X1GM

But those buying components for a manufacturer ain't 'people'. They will expect only a tiny number of failures from that component - anything else would be a nonsense. Given the number of different components in the average piece of consumer electronics. Which means the component makers must have decent quality control.

Dunno. Cheap electronics from the major UK supermarkets ain't worth having. Go to Lidl or Aldi for such things - they are miles better. The Germans obviously expect more.

Labour rates mean repairing many consumer goods ain't worth it, commerically. And, of course SM components. ;-)

--
*No sentence fragments *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Although I neglected to make it clear, I was commenting on the lack of quality control in production of finished electronic gear, namely consumer electronic gear.

For medical or avionics equipment there are very likely to be numerous levels of quality control, from testing of incoming components to rigorous testing of the finished products.

For portable CD players that retail for less than $10, I seriously doubt that any QC exists. The components are most likely selected/chosen as whatever is cheapest/on sale that week.

Many manufacturers are thinking in terms of the Harbor Freight business model. The products are built at the cheapest price point, and the ones that fail soon (or fail to work) are cheerfully replaced with another one. The failed units get sold off in bulk to someone else who might try to salvage/refurbish a number of working products from the failed ones, and/or just separate the materials and sell them as scrap.

As someone else mentioned, when a product fails prematurely, the consumer may choose another brand for the next purchase, which very likely could have been made by the same manufacturer, but with a different brand name on it.

The last time I looked, the supply of refurbished equipment was ample, but there are no profits to be made from refurbing those $10 CD players. They're just filler for the landfills, like so many other consumer goods produced presently.

Refurbishing is relatively expensive due to transportation costs, repairing, repackaging and redistribution.

-- Cheers, WB .............

It depends on your definition of 'a little time'. My primary source of information is

It would appear you are at least doubling the MTBF (mean time between failures) by using high quality caps. That would mean if you replace the caps in a two year old monitor, it will probably last an additional 4 years before it is necessary to replace them again. At worst, that is a significant improvement.

When I look at the cost, power consumption, clarity, and design of 4 year old LCD monitors vrs those one or two years old, I doubt that in

5 years you would be asked to repair many 7 year old monitors.

I would agree, having to redo the replacement every two years could cause speculation about your skills.

PlainBill

[snip]

[snip]

Agreed. Though, perhaps another way of combining my questions would be: "Would a different design approach result in a (much) longer life expectancy for this type of product?"

Most of the monitors I've been repairing are in the 2-3 year old range. It's possible that older monitors have already made their way to The Great Recycling Bin in the Sky. :-/

I don't have a fragile ego! :> Rather, I am concerned as to whether or not I am doing these people (read original post: "a local non-profit") a *real* service or just buying them "a little time". I.e., when I am no longer affiliated with them -- and there is a high probability that they won't have someone with my skillset available -- will they just see this whole pattern repeat itself N months/years hence?

And, from a selfish perspective, what can *I* learn from these failures to help me design products that don't exhibit them!

Oh there I'd agree. It is cheaper simply to replace faulty units than test each and every one fully before dispatch. However there will still be quality control as no profit will be made if the failure rate is too high. But that quality control could well consist of just insisting the component parts are to a standard.

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*Sorry, I don\'t date outside my species.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Most power supplies I see already use inductors in the DC filters. You are dealing with a trade off between the switching frequency, transformer size, and capacitance. That usually results in a 'choose two of the above' situation.

The only possible change that I am aware of is to use replacements that have a polymer electrolyte. Frankly, you would be in a better position to determine if that would be cost effective.

The discussion at badcaps indicates you can expect at least double the life by using top grade caps. If you are repairing monitors 2-3 years old, you can expect they will last 4-6 years more after the repair. Assuming you would be still available to do your excellent repair work, by that time I would expect a new equivalent monitor would cost as much as repairing the existing monitor. At that point, repair is pointless.

PlainBill

Logically, that should be "at most doubling the MTBF"; remember that failures can include leaking of corrosive goo and short-circuiting.

It's not surprising that 'badcaps.net' overemphasizes capacitor quality issues, but my ire is drawn rather to the mechanical design decisions that put the tiniest available capacitors onto a circuit board with zero clearance to adjacent components. An old design criterion was 'one amp ripple current to one square inch of surface area' for the purpose of dissipating the inevitable heat buildup.

Empty space is GOOD. Don't minimize it!

To get extra operational margins, it's useful to go to the next larger size of capacitor (in the case of tight-packed capacitors, that has to be longer case sizes, because bigger diameters won't fit). In theory, capacitors (like semiconductors and inductors) can benefit from heatsinking. Has anyone tried it?