WHITE PAPERS/TECHNICAL ARTICLES 

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.

What is an Intelligent Power Supply? And has it Arrived?

by Adam Rosenstein and Lonnie Friend, Pioneer Magnetics -- , 2/1/2004

Until recently, power supplies have been brute-force devices that have been pretty much deaf, dumb and blind. They have been able to communicate with the systems they serve only with difficulty and in a rudimentary manner. The power supply industry has begun to provide more intelligence in their products, but in a piecemeal fashion and in reaction to specific needs of particular markets. So, communication protocols and operating standards have not emerged, leaving customers to fend for themselves to develop and support hardware and software interfaces. The effect has been to increase system development costs and lengthen time-to-market cycles.

Intelligence is desirable in any high-reliability system. It was first employed in telecom applications to help solve the difficulty of their remote locations. Applications have expanded to include system servers, semi-conductor test and process control equipment, broadcast, fuel cell sites and any application that requires a high degree of system availability and failure avoidance. Due to the diverse needs of these applications, there is as equally diverse definition of what intelligence is, depending on one's perspective and the markets served.

The Intelligent Power Supply (IPS) Interface is a PC-based windows software program. What Is Intelligence? The real question is one of what intelligence in a power supply or system should be able to do. In an ideal world, the truly Intelligent Power Supply (IPS) will be able to: ·Communicate: Power supplies are analog devices and communicate via analog and TTL signals to provide system status information and control. The systems they serve are predominately digital, and communications between them and the power supply are achieved with difficulty. Without a vendor-supplied intelligent interface, the customer is faced with the prospect of designing and implementing his own custom hardware and software protocol. The ideal IPS should be able to communicate with the system and the outside world directly via all standard protocols including I2C, RS232, RS485, CAN and TCP/IP to name just a few.

·Control: The IPS should permit easy local and remote command and control without extensive software development on the part of the system's integrator. The commands should be intuitive and user-friendly. This "plug-n-play" capability avoids the typical development process required to integrate "intelligent" power into an "intelligent" system. Finally, the IPS should be completely programmable, permitting full adjustment of output voltage and current as well as enabling/disabling of the power system itself.

·Monitor: The IPS should be able to provide digital information describing all operating parameters, including input voltage, output voltage, output current, internal temperature, fan operation, logged power-on hours and a myriad of other attributes that indicate its general health.

·Provide Alarms and Failure Avoidance: The IPS should be able to issue alarms and take steps to save itself and the system from coming down. For example, the IPS should:

1. Issue a warning when internal temperatures become too high. This may be caused by higher than normal ambient temperature or a clogged fan filter. In any event, the IPS must be able to signal that attention is needed.

2. Issue a warning if the input voltage approaches a dangerously low point. When the input voltage becomes too low to support the load, the non-intelligent power supply will shut down to save itself. This results in system crashing.

The Intelligent Power Supply (IPS) allows the user to remotely control and monitor all power supply functions and to record data for tracking purposes.

Most importantly, in both of these examples, the IPS should be able to take steps to control the situation until help arrives without allowing the system crash that usually occurs. In these conditions, the IPS should intelligently de-rate itself and adjust its operation in reaction to changing conditions. This is truly intelligent and analogous to a running man who decides to walk because he is tired yet must continue his journey.

Industry Progress

Has the truly intelligent power supply arrived? It has in the form of Pioneer Magnetics' ICON™ technology that accomplishes all of the above and more. ICON is available over Pioneer's entire product line from a 1 kW rectifier to a megawatt power system.

The rest of the industry has not by any means been standing still. Many suppliers have developed, to varying degrees, some aspects of the IPS. Cherokee, Power One and others have released some specific products that provide I²C, RS232 and other protocols. Argus, a provider to the telecom industry, offers a micro-controlled rectifier that addresses certain specialized needs. And Lambda has introduced its "Vega SmartPlus" product line.

The power supply industry is paying attention to and trying to anticipate its customers' needs and taking steps to meet them. What is certain in our minds is that the micro-processor will continue to play an ever-increasing role in that regard.

©2010 Pioneer Magnetics