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 POWER SUPPLY REPAIR ARTICLE 

Some Power Supply Repair Jobs Only Make Things Worse

By Jerry Rosenstein

November 25, 2009

How weird is it when your repair business involves repairing repairs?

Pioneer Magnetics, a manufacturer of high-end commercial AC to DC and DC to DC standard and custom switching power supplies, recently shipped its 700,000 th power supply since it started counting its products in the 1980s. COO and President Jerry Rosenstein’s estimates, easily over 50% of the number are still in use. Of those, about 10% or 35,000 units should be coming back for repair or refurbishment each year.

Why? Don’t well designed-well built power supplies last forever?

It’s not likely that most of these power supplies are out there happily operating years past their expected lifeline even though the demanded MTBF of power supplies has gone from 25K hours just a few decades ago to well over 1M hours today. Although some of PMI’s product lines have exceeded 3M hours, customers tend to ignore the fact that no matter how well power supplies are designed and manufactured, there are a few weak links in all power supply company’s designs.

Of the hundreds of components – all meeting design specifications and a variety of in-house testing at PMI– the electrolytic capacitors and fan motors will not last forever. Rosenstein recommends that roughly every five years, the units should be returned to the manufacturer. These components need to be replaced, the PCB assemblies need to be cleaned, re-tested and then sent out again as new.

However, there is another issue (besides components) that comes into play. It’s the actual application. Is the power supply humming away in some benign office environment or could something else be happening effecting the overall operation of the product?

Many power supplies wind up in locations where there was no consideration of a harsh environment. Typically, power supplies are not happy campers when located on a tropical island with wind, rain, and salt water pouring into the systems. Platforms in the middle of an ocean, product sitting on top of a Louisiana telephone pole during hurricane season and Sahara desert dust storms also create issues. Rosenstein happened to be at a customer site when “A gecko got into a cabinet, and everything went ‘kaboom.’”

So, with customers ignoring the need to refurbish power supplies, not understanding that harsh, corrosive environments could further damage products, how many power supplies requiring repair or refurbishment does PMI actually get back on a yearly basis?

50,000? 100,000? The actual number is more like 800!

Where have all the PMI power supplies gone? Rosenstein would like to believe that his company is designing and manufacturing the perfect power supply --- He would love to claim that his products never fail!

Not likely.

Rosenstein suspects that many of the 35,000 units he estimates requiring some sort of repair or refurbishment go to third party power supply repair houses. Not that there’s anything intrinsically wrong about third party repairs. In fact, Pioneer Magnetics is working directly with several certified repair houses.

“I’m not saying they’re all bad by any stretch,” says Rosenstein, but there are companies out there representing that they have the technical ability to repair products manufactured by all power supply companies. Take a look at the third-party websites. It’s amazing what is represented. Some of these companies even state that there is no problem repairing a PMI power supply. Yet, it would be impossible. A third-party repair house does not have access to our proprietary material – material that is specifically designed for a PMI power supply --- some of which, “we keep under lock and key,” so to speak!

On a recent tour of a repair house that Rosenstein declined to name, he noted boxes of capacitors from the 1980s and old fan motors on the shelves that had been cannibalized from “old clunkers” that were purchased on E-bay.

Unfortunately, it is quite apparent to Rosenstein that “the blind is leading the blind. It seems that the end user looks for repair houses that are close by and the cheapest possible.

It is interesting that during the last several years, Rosenstein is seeing an increasing amount of units being retuned to PMI that have been (very) badly repaired. “It’s awful what we are finding. At a time when an end user has a system down – they’re desperate – they end up with a product that ultimately that needs to be scrapped. It’s obvious that someone tried to do a repair and botched the job. Typically, we’ll get power supplies back with broken connectors and wires. Missing or wrong components are installed. Traces are burned or missing. To make matters worse, we sometimes see little notes from the repair house to the customer indicating that the power supply could not be repaired due to PMI’s bad design.”

Repairing a power supply isn’t quite as simple as swapping out a few components. As a case in point, Rosenstein says that Pioneer has developed a special technique to repair hybrids – a ceramic daughter board that has a mix of through-hole and SMT components. We designed special equipment to remove a multi-pin device without damaging the hybrid itself or the surround area of the motherboard. “We’re seeing units coming back with damaged hybrids -- clearly someone tried to repair it but used the wrong soldering iron – pins were on the board, working were destroyed and circuit traces were burned.”

Why would anyone risk a bad repair on a product that retails for a thousand dollars, or more? Two words: Cost savings. Rosenstein says that his company’s prices are quite reasonable given what his company does ensuring a repaired or refurbished product goes back out for a lengthy period of time.

Some third party repair houses may charge as much as 50% less. “It’s amazing that people take one of the most expensive components in a system design and start looking for a cheap deal when it comes to repairs,” he says.

So, what is the answer? If at all possible, customers and end users should send product back to the original power supply vendor. However, if it is not possible, the end user needs to identify a reliable third-party repair house that has been surveyed ensuring strong good ESD controls. ISO quality process must be in place Warranted material must be used and complete testing i.e. burn-in is done. Even more important is to determine if a third party repair has the ability to do a true, root cause analysis. Rosenstein says that at the very least, end users must conduct some due diligence before signing on the dotted line, especially if the repair prices seem almost too good to be true.

There is that old adage – Pay me now or pay me later. It seems that this phrase truly fits when it comes to repairing power supplies.

 

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