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Fat Caps & Ripple Current… Power Supplies & Logic Cards




Below the ripple voltage chart explanation is an email thread that I thought would be interesting to share. Note, permission was provided to reprint it here. The subject of the email is: Fat Caps & Ripple Current… The following ripple voltage chart is provided for reference material. Understanding the Ripple Voltage Drawing Above The faster [...]






Click to read more about: Fat Caps & Ripple Current… Power Supplies & Logic Cards

Below the ripple voltage chart explanation is an email thread that I thought would be interesting to share. Note, permission was provided to reprint it here. The subject of the email is: Fat Caps & Ripple Current…

The following ripple voltage chart is provided for reference material.

Ripple Voltage

Capacitor Discharge Results in Ripple Current

Understanding the Ripple Voltage Drawing Above

The faster the capacitor discharges, the more ripple will be present. If the capacitor in the circuit is underrated or completely bad, it will not properly hold a charge, and thus the electronics circuit will have maximum ripple present. When a capacitance filtering circuit is faulty, picture the valleys on the voltage being very deep relative to the peaks, and the ripple current will shoot up proportionally in the circuit, with the result of a major increase in heat being generated in all the circuits supplied by the power supply voltage that should be a regulated level DC, which would now effectively be an AC ripple voltage. This will quickly result in thermal breakdowns in various components on the circuit boards, causing a cascading component(s) failure(s) affect.

Picture Courtesy of HyperPhysics Department of Georgia State UniversityDevelopment of Ripple Expressions

I thought it would be interesting and educational to hear from an expert in the engineering and circuit design field. The following is the email dialog conversation I had with Dean Palmer, engineer/owner of MicroDyne Engineering, LLC, an electronics research, design, and development services company, located in Queen Creek, Arizona, USA.

Dear Jim,

I stumbled upon your very informative “Capacitors” web page today and enjoyed your article on DIY lead free soldering and circuit repairs. I too encourage people to try to service their own stuff where possible. And this leads me to the following question:

I have a Panasonic DVD player/recorder (Model DMR-ES15) that has a recurrent “U61″ error that, in the owner’s literature, is stated more or less to be a power related problem. So I open up the unit and discover a single (but large) aluminum electrolytic cap on the main power converter sourced directly from the DC rectified AC mains. A check around the Web and I see that many owners of this product have been experiencing similar “U61″ problems with their units; some failing after only a few months of operation; most just after their 1 year warranty expires. So I get my trusty Tek 2467 scope on the circuit and I see a HUGE amount of ripple at the pins of the capacitor, yet the capacitor tests good! I replace it anyway with a good quality low ESR hi-temp Nichicon and still there is terrible ripple on that node. The power supply seems to have a load related voltage regulation problem and there is a lot of ripple and harmonic noise on the output. Doubling up on the capacitor even though there was no room on the board (had to dead-bug it) was the only way I could quiet down the circuit.

After visiting your page, I too thought that this part (or others) had possibly been damaged by the lead-free thing and the higher heat production methods used to build this unit – there is lead-free solder everywhere, even though the date of manufacture was 2006. But now I’m convinced that the part was actually under-designed for the requirements of the circuit. And, I’ve seen high ripple on computer mother board caps from time to time that caused all sorts of malfunctions and random errors/reboots, and also in a couple of LCD displays I worked on. In addition, there is an under-designed heat sink on the video processor chip in this DVD player – it gets seriously frying hot when playing back or recording a DVD – which cannot be good for the chip or it’s tiny ball grid array solder connections.

So my question to you is, why are manufacturers under-designing the circuitry in these products? Are these companies so desperate to maximize profits that they apply MTBF and service data back into the manufacturing process to find ways to cut back on design quality and circuit components to just get them through the warranty period? I’ve heard they can actually tweak this down to a granularity of weeks. Or, are we just seeing rampant designer incompetence all across the board – engineers who do not know how to do simple calculations for ripple current and thermal dissipation? Could these guys even balance their check books? What are they teaching in the EE programs these days???

I would be very interested in your thoughts on this! At any rate, Ha, it keeps me in business.

Thanks very much!


Dean Palmer
Engineer, NPD

MicroDyne Engineering, LLC

Queen Creek, Arizona
USA
480.888.0600
www.microdyneeng.com

Jim W. wrote back:

Hello Dean,

Wow, you got my mind filled with all types of thoughts. First off, my experience in the electronics field goes back more years than I care to imagine: http://jimwarholic.com/about.

Bad Nichicon Capacitors on Apple iMac G5 Computer

I constantly see problems related to component failures more and more frequently. I honestly believe that everything is designed with a time value. Capacitors have a certain time value to heat rating. If you operate a capacitor near its maximum rating, the capacitor will last X amount of time. If you operate a capacitor at 1/2 the maximum rating, you will likely get 2X life or more out of the capacitor. So, it comes down to the engineers specifying the ratings on the capacitors without fully understanding the time value. The differences in costs are very very minuscule if anything at all. But, when they call for a value of 2200 uF cap at 10 volts because the maximum voltage might be only 10 volts, but the circuit is actually operating at 10 volts, then in essence the capacitor is operating at 100% of its maximum voltage. They could just as easily installed a 16 volt capacitor, that might be slightly larger, (though they would have had to design for this larger size) but would have lasted probably more than twice as long, because it would have only been operating at 63% of its maximum operating voltage, and more than likely would have operated at a cooler temperature too. So, the engineers need to take into account the time value, which is probably not being stressed at all.

Bad Rubycon MCZ CapsThese power circuits generate tons of heat on their own, and that also is not being taken into account. This causes a cascade effect, which causes more heat, and more breakdown, and more heat, etc.

Here are a couple of pointers to consider when troubleshooting power supply circuits. Most power supply circuits start with full wave rectification. If only one half of the rectification process is working, the capacitors will not be able to filter the voltage properly. Also, there are many times the regulator circuits are failing. So, the voltage drops under load, the regulator can not keep up and therefore the caps try to maintain the voltage, but heat builds up due to excessive current draw.

With the push towards smaller, more compact designs, this causes the engineers to simply go with the smallest of the specs that they can get away with. So, when the final design comes out, and it goes out for build, the builder (assembly house) simply follows the component specs and then gets its supply of components sent from the manufacturer. Once again, at each leg of the manufacturing process, the specs are used as the guide. If the specs are just of a minimal value, and the manufacturer supplies the component with that value, the question comes down to, who’s fault is it?

Did the engineer look at a data sheet of components and see that the standard is a 2000 hr. rated capacitor at TEMP, OP. MAX:105(DEGREE C) and in essence say that will be good enough? Probably. Did the manufacturer of the component, simply target the minimum standard? Probably.

Have computer companies looked at the life cycle of computers being somewhere between three and five years, and say, that if it lasts for four or five years it’s probably good enough? My guess is yes.

However, computers have gotten to the point where even if you go twice as fast for most activities, it really doesn’t matter much. So, more and more of us are keeping our computers for a longer period of time.

Does the manufacturer hold some degree of responsibility for a design that should last longer than the warranty period? And if so, how long? The short answer, is yes. However, the long answer is much more complex than meets the eye. There is always a trade off between price, design, and life expectancy.

I was really ticked off, and still am ticked off to this day, when my Apple failed, two months out of warranty, and the Genius Bar folks said, “Why don’t you just buy a new iMac? The price of a new one is only several hundred dollars more than the parts for the old one.” It was at that point, I had to taken action in my own hands. http://jimwarholic.com/apple

Thank you for listening. Maybe I will post this online, without adding your name to the mix.

Regards,

Jim

Dean Palmer wrote:

Thanks Jim for answering my question! I appreciate your comments very much. And I am right with you on being very upset that your MAC dies right after the warranty period is up. I think that manufacturers should be held accountable for the quality of their products. I know that in reality, it’s “Buyer Beware!” – “If you don’t like my brand, buy someone else’s” … but really, is that the way you’d want YOUR company to do business? The whole attitude out there seems to be “make as much money as you can with as little cost as possible put into it…” – that seems to be capitalism at its worst where greed and lust for wealth and profit creates an environment where crap is king and corporations are driven to make things as cheap as they can get away with! But in the end, we are ALL consumers of products and services. Even the CEO Of SONY, or Toshiba, or in my case, Panasonic – all are consumers. When he goes to buy his Mercedes Benz, would HE be satisfied that it just (barely) meets the warranty period before some major failure occurs? No! He’ll be on the phone to Mercedes to raise hell about it!

So whatever happened to having pride in your product and its quality of workmanship? As you pointed out, for just a few cents more, a better suited capacitor could have been used in the circuit and this would have avoided thousands of upset consumers and calls to service centers. The way I see it, it’s a reputation thing as well as being an ethical matter. When I do a design for my Clients, I want my design to be the best it can be. I was raised by a very demanding and “military authoritative” father who insisted on perfection; to do the best job you can do – or don’t do the job at all. So it’s in my makeup to give my Clients 110 percent on every project that crosses my desk. I will cut corners in design or materials ONLY if they tell me to do so, but with great reservation and reluctance. And for the money I pay for a new TV set, I expect it to last for many years. My parents had an old Motorola Quasar “Works In The Drawer” TV that we had for probably 12 or more years. It was a hybrid design made with tubes and transistors, and a couple ICs. It lasted until the picture tube finally gave up. Wow! But these days, this kind of quality and reliability just isn’t seen anymore. It’s very sad really, especially in the light of technology being so advanced – you could build a DVD player that should last 20 years. And as consumers, have we, for the most part, become used to mediocrity in everything we buy?

No matter what brand I choose, it’s gonna have problems? There just has to be a balance between profits and getting your new gizmo to market before the competition, and building a product of decent quality and reliability. And it seems that the consumer public – you and me included – needs to drive this shift in corporate paradigm by DEMANDING high quality and exceptional reliability from manufacturers. And by the same token, we should also be willing to pay a little extra for it. If I want to buy some off-brand TV set for 79 bucks at Walmart, I can do that, and I’ll get what I get. But when I pay $895.00 for a bran new shiny SONY with all the bells and whistles that even pours me coffee, I EXPECT it to last and last and last. Maybe I’m too much the old school, I don’t know. But I would NEVER design in a 10 volt capacitor into a 10 volt circuit! I “might” design a 20 volt part in there if I’m in a good mood. But I’ll probably and most likely use a 50 volter! And really, what does that do to the end cost of the product? Not much.

There are so many other factors that go into the total cost to manufacture and sell an appliance. One of the biggies is that damn paranoia about lead in the environment (RoHS)! For God’s Sake, don’t people know that lead comes from the ground in the first place? How much of this is political and how much of it really makes sense in the name of public health and the environment? And a lot of the cost to make a product comes from efficiency and the internal structure of the company. Some companies are so wasteful and inefficient that they could build their products lined with gold if they’d just cut out the waste and inefficient practices, and perhaps limit those million dollar bonuses to CEOs. The list is endless, but taking such clean up measures would pay for a better capacitor, diode, or heat sink a thousand fold. And personally, I will pay more as long as I KNOW that I am buying quality. The tires on my car and the brakes I use are the best money can buy. There are some things you just don’t cheapen your way out of! I can buy a cheap DVD player if I want. But I probably won’t. I want good quality at a reasonable price. And I adhere to the Three-To-One policy: for a one year warranty, a product should last three years at the very minimum! Really, warranties are to protect the consumer from DOAs and accidental defects that can sometimes occur in manufacturing or materials. It should NOT be an indicator as to how long I can expect the product to work!

I’ve enjoyed our conversation Jim! Thank you for allowing me to rant. And you may use my name in connection with any of my comments you wish to publish. I hope if you do publish this dialog, it will get people visiting your site to thinking – and demanding – quality and reliability. Next to a fair price, what else matters?

-Dean Palmer

Dean Palmer
Engineer, NPD

MicroDyne Engineering, LLC

Queen Creek, Arizona
USA
480.888.0600
www.microdyneeng.com

“MicroDyne Engineering provides Electronics Design, Research and Development (R&D) and Prototype Design and Assembly services to customers and clients who wish to bring a new technology product idea from concept to actual hardware realization. Their goal is to provide clients and customers with product designs and solutions for markets and applications that would benefit from innovation and value-added product designs.

Reverse-Engineering services can also be provided for existing technology products and devices where the original documentation and component sources are non existent or no longer available.”

Thank you Dean for sharing your insight into the wonderful world of electronics research, design, and product development, with this first hand look into engineering and design of electronics’ products. The mind of an engineer is …

I would also like to extend a big thank you to Dean for granting permission to reprint this here.

Note, all copyrights are reserved.

Regards,

Jim Warholic

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Why I Bought an Apple MacBook Pro




My PC friends probably think I am crazy, but the weight of the decision of why I purchased an Apple MacBook Pro fell on five key points of comparisons to other laptop computers. Apple MacBook Pro vs. Netbook PCs Ease of Use Quality Versatility Form Factor Value (Price divided by the first four points) My [...]






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My PC friends probably think I am crazy, but the weight of the decision of why I purchased an Apple MacBook Pro fell on five key points of comparisons to other laptop computers.


Apple MacBook Pro vs. Netbook PCs

  1. Ease of Use
  2. Quality
  3. Versatility
  4. Form Factor
  5. Value (Price divided by the first four points)

My notebook story begins with searching for a good quality, fast speed, good display screen, a comfortable track pad, good software, ease of use, long life battery, ability to do videos and pictures well, but low priced netbook or small laptop for mobile/portable/travel use. I quickly found that there is no such creature like this.

I stopped in over at Fry’s and started playing with the various new Windows 7 Netbooks from Acer and MSI. At first glance I wanted to really like these netbooks, but it was only a short lived infatuation. There were more than a few barriers to taking these netbooks from a foolish liking to an in-depth affection. For one, they were small. Now, that may be good in one aspect for portability, but for another aspect of screen size, it was very difficult to get comfortable with the small screen size. Those of us that are requiring reading glasses are sure to find these screens are much too small. Sure, the price was low at around $350.00, but look at what you are getting for that.

With these netbooks, this really is a case of getting what you pay for. Slow processor speeds, low memory, no dvd/cd drive, and a new operating system with Windows 7 that is all déjà vu. The Windows 7 operating system loaded on these netbooks feels like an upgraded version of Windows XP, with things moved around a bit and other things very difficult to find. Of course, this is the dominate format for these netbooks. Simple things like how to change the icon sizes on the desktop took me 10 minutes to find. And, that was after I spoke with the sales people, though that brings up the topic of the sales people may not have the best of training either. That’s another story. In any case, three of the sales people that I spoke with could not figure it out. It wasn’t located in the Windows 7 control panel area, as one would think. Finally I did what would be a right click with a mouse on the desktop, though I am not sure how I did it with the netbook trackpad, but I was able to change the default icon size to a smaller size.

Speaking of touchpads or trackpads, I have grown up on a mouse in the house for both PCs and Macs. So, this really was my first time investigating and comparing track pads. The trackpads on these netbooks and mini laptops seemed to be engineering afterthoughts. Actually, they lacked quality engineering and no consumer testing. The one that bugged the heck out of me the most was the trackpad on the MSI mini laptop. It felt like sandpaper on the tips of my fingers after playing with it for 10 minutes. Actually, I ended up pulling another customer over and asking him what he thought of the touchpad. His thoughts were exactly the same as mine. The trackpad had a very textured finish that was not comfortable to the touch. I can only imagine what it would be like after navigating with this trackpad for an hour or so. I would have to put Band-Aids on my fingers. Definitely not a very good touchy-feely experience.

So, I decide that maybe I needed to move up in price and screen size. I moved up to the mid range for laptops. However, there seemed to be a void in the size from the 8.9 inch – 11 inch version mini laptops to the 15 inch larger laptops. Price started going up significantly as I wanted a more powerful laptop that could do various types of mult-tasking, and still stay with a useful but compact size. Next thing I knew, I was up around the $700.00 price tag. But, still I had issues with trackpads, and the lack of ease of use.

So, I ventured over to the Mac table. Being an equal opportunity user of both Windows PCs and Macs and am well versed in both the PC and Mac land, having owned many versions of Windows PCs and an iMac G5 for a number of years. I have also had the opportunity to have hands on experience by having friends allowing me to play with their MacBooks for various applications. When I went over to the Mac table, it was a breath of heaven to feel and touch the new MacBooks.

MacBook Pro
My First Thoughts on the MacBook and MacBook Pro

The first thing that stood out to me was the ease of use. The trackpads are very very easy to use. Having a Multi-Touch Trackpad that is large, smooth, extremely powerful, two finger scroll capable, two finger pinch zoom capable, two finger rotate, and even two finger right click or secondary click capable with the full complement of right click commands available. Additional trackpad features include three finger swipe navigation to go forward or back in browser history, four finger swipe left to right to switch applications, or four finger swipe up down for exposing the open applications. You can even set the one finger to tap to click, dragging, drag lock, and secondary click to bottom left or bottom right corner. Track speed, double-click speed, and scrolling speed can all be individually adjusted to just the way you want them.

MacBook Pro Keyboard Trackpad

With this MacBook Trackpad, you will quickly find out that a person can go from using a mouse to very easily using the Multi-Touch Trackpad in no time flat.

Another aspect of the MacBook that makes it a joy to work with, is the ease of use of the Mac OS X Snow Leopard. While any new software will take time getting use to, the learning curve for the Mac OS X is very fast. I think part of the reason for this is the intuitiveness of how the things are laid out. Apple also has some very good quick training videos that are quite helpful. Take a look at some of the Mac tutorials on how to do things.

Mac OS X Snow Leopard operating system is a pleasure to work with. It is very intuitive, which makes for a very easy transition to go from working with a Windows based machines to a Mac based operating systems. Of course, I am a bit biased in this area, since I have been using both Windows and Mac machines for quite some time. Never the less, some friends of mine who had been with Windows their whole lives, recently made the switch to Mac, and the operating system switch proved to be a very easy transition for them.

The high quality of the Apple MacBooks can not be overstated. Everything fits together like a form fitting glove. The opening of the screen display has just the right amount of hinge tightness. As I stated before, the trackpad is very smooth, and seems to just fit perfectly for your hands and fingers on the keyboard area. The keyboard has automatic backlighting, which in dim environments is great for quick reference. The MacBook Pro comes in a very sleek, 1.08 inches thin, aluminum unibody construction.

I bought the 13.3 inch MacBook Pro with the glossy widescreen display. This for me was the perfect fit for size and portability, but has plenty of desktop space with a screen of 1280-by-800 pixel resolution, made this one the ideal laptop solution for viewing documents, web sites, videos, and pictures.

The weight of the MacBook Pro 13 inch at 4.7 pounds is very manageable. It easily fits into a briefcase or backpack. I also suggest a carrying case to protect your MacBook. I decided to go with the Incase Nylon Sleeve Case for the Apple 13 inch MacBook Pro. The MacBook Pro fits perfectly in this padded case and provides extra storage areas on both sides for accessories. The case and the MacBook Pro worked out perfectly for a recent vacation trip from California to Florida with several layovers. The case added the extra protection and allowed me to quickly place the MacBook in my carryon suitcase, and quickly remove it for airport security checks. The case also comes with a removable shoulder strap and is available in three colors, black, graphite, and mustard.

The MacBook Pro is such a pleasure to use for all aspects of computing. For example, when it comes to viewing video on the screen, it is second to none. The display is rich in color, bright, and vivid to look at. Movies are cool to watch and when it comes to catching up on your television shows like Flash Forward episodes, it is incredible to watch it on the MacBook. It’s as though watching it on the MacBook Pro is better than on the TV screen. The stereo sound quality from the computer is great too. The audio level has decibels of sound to spare. You can actually make the sound too loud for others in the room. Forget trying that with any other netbook.

With the built-in iSight camera and microphone, doing a Google Video Chat was simply amazing. The camera and built-in microphone worked great together. I was able to use the camera in both low light and regular lighting conditions. The chat session was perfect. There was no audio feedback and the person on the other end said the audio and video were perfect too.

The battery life is rated at 7 hours, but that is under somewhat controlled conditions. Apple quotes the following from their website:

Testing conducted by Apple in May 2009 using preproduction 2.53GHz Intel Core 2 Duo-based MacBook Pro units. Battery life depends on configuration and use. See www.apple.com/batteries for more information. The wireless productivity test measures battery life by wirelessly browsing various websites and editing text in a word processing document with display brightness set to 50%.

I typically like my screen brighter than 50%, and was able to generally get about 5+ hours of battery usage on three battery cycles. However, I was playing videos, browsing the Internet through wireless connections, and searching for other wireless Internet connections during this time.

The charging plug is held in place with a super strong magnet, which if someone catches the cord will simply pull the connector off the MacBook without pulling the MacBook down to the floor. Definitely a great safety feature. the charger is very compact, and fits nice and flat inside one of the Incase pockets I bought for the MacBook Pro.

The MacBook Pro 13 inch that I purchased has the 2.53GHz Intel Core 2 Duo processor, 4GB (two 2GB SO-DIMMs) of 1066MHz DDR3 SDRAM; which supports up to 8GB of memory, 250GB Serial ATA; 5400 rpm hard drive, and 8x SuperDrive (DVD±R DL/DVD±RW/CD-RW).

MacBook Pro Features

 MacBook Pro Features

Left Side View of MacBook Pro 13 Inch Model

Connections and Expansion Ports

  • MagSafe power port
  • Gigabit Ethernet port
  • One FireWire 800 port (up to 800 Mbps)
  • Mini DisplayPort
  • Two USB 2.0 ports (up to 480 Mbps)
  • SD card slot
  • Audio in/out
  • Kensington lock slot

Communications

  • Built-in AirPort Extreme Wi-Fi wireless networking (based on IEEE 802.11n draft specification); IEEE 802.11a/b/g compatible
  • Built-in Bluetooth 2.1 + EDR (Enhanced Data Rate)
  • Built-in 10/100/1000BASE-T Gigabit Ethernet (RJ-45 connector)

Audio

  • Built-in stereo speakers
  • Built-in omnidirectional microphone
  • Combined optical digital output/headphone out (user-selectable analog audio line in)
  • Supports Apple Stereo Headset with microphone

Read more about all the MacBook Pro features today.

By the way, if a person really wants to have their cake and eat it too, in the form of Windows 7 on their MacBook, there is another feature that lets a person load any operating system they wish. Boot Camp is a utility included with Apple Inc.’s Mac OS X v10.5 "Leopard" and v10.6 "Snow Leopard" operating systems that assists users in installing Microsoft Windows XP, Vista or 7 on Intel-based Macintosh computers. Boot Camp guides users through non-destructive re-partitioning (including resizing of an existing HFS+ partition, if necessary) of their hard disk drive and using the Mac OS X Leopard disc to install Windows drivers. In addition to device drivers for the hardware, the disc includes an applet for the Windows control panel for selecting the boot operating system.

In addition to Boot Camp, there are other avenues that are also available such as, VMware Fusion 3 and Parallels Desktop that provide the means of loading Microsoft Windows and other non Windows operating systems such as Linux OS onto the MacBook computers. Both VMware Fusion 3 and Parallels Desktop are helpful software applications that allow folks to run Windows applications directly and concurrently on their MacBooks and quickly switch between the two.

Purchase VMware Fusion 3

VMware Fusion 3

Purchase Parallels Desktop

Parallels Desktop

 

VirtualBox

There is also an open source software, VirtualBox, available from Sun. VirtualBox is an x86 virtualization software package, originally created by German software company Innotek, now developed by Sun Microsystems as part of its Sun xVM virtualization platform. It is installed on an existing host operating system; within this application, additional operating systems, each known as a Guest OS, can be loaded and run, each with its own virtual environment.

“Presently, VirtualBox runs on Windows, Linux, Macintosh and OpenSolaris hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0, 2000, XP, Server 2003, Vista, Windows 7), DOS/Windows 3.x, Linux (2.4 and 2.6), Solaris and OpenSolaris, and OpenBSD.”

I have to say that the MacBook Pro is really a great all purpose laptop computer for business, school, and personal use. With ease of use, superb quality, immense versatility, and an awesome form factor, the value of this MacBook Pro computer is outstanding. You won’t want to leave home without it! Checkout the online Amazon Apple Store deals today.

Jim Warholic

Jim Warholic is President of Professional Web Services, Inc., an Internet Marketing Services firm specializing in B2B and B2C Internet marketing, SEO services, online advertising, and online branding strategies. Contact Professional Web Services today.

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Soldering Tips For Lead-Free Solder




The days of using a 20 watt soldering iron from Radio Shack are long gone when it comes to repairing lead free soldered circuits in Apple Computers, PCs, and other lead-free electronics equipment. With multilayer boards, thick ground planes and power planes, and high temperature circuit board materials, along with countries having bans on the [...]






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The days of using a 20 watt soldering iron from Radio Shack are long gone when it comes to repairing lead free soldered circuits in Apple Computers, PCs, and other lead-free electronics equipment.

With multilayer boards, thick ground planes and power planes, and high temperature circuit board materials, along with countries having bans on the use of leaded solder in circuit boards; electronic components are now being attached using lead-free wave soldering or pick-and-place machines using conductive epoxy flux adhesives and then heat cured. All of this adds up to quite a bit of difficulty in reworking and repairing circuit boards today.

CHIPQUIK at JWestSales.com While it is good to keep our environment clean, I think the wide spread use of lead-free solder in printed circuit board assembly processes is a case filled with a manufacturing life of unintended consequences. There are major challenges that have and continue to affect printed circuit board manufacturing around the world. First off, PCB materials must be able to withstand lead-free soldering temperatures of up to 260[degrees]C during the assembly operation. [1] This in itself, requires the use of more expensive, and much more difficult materials to work with at the PCB manufacturing stages. Not only is the multilayer construction much more difficult to deal with, but the drilling of the holes in thick multilayer circuit boards, with circuit board materials that are of a “harder” material nature, as compared to traditional FR-4 resin systems (not designed for lead-free), directly adds to the manufacturing costs involved.

I also find it interesting, that about the time where the world (pushed by the European Union) started converting over to using lead-free PCB manufacturing techniques, there seems to be a correlation between the electrolytic capacitor failures that started to occur a short time later in TVs, Set-Top Boxes, Computers, PCs from Dell, Apple, and other computer manufacturers, along with a host of other high powered electronic gadgets. I have no way of proving it, but I suspect that many of these components were hit with a large temperature blast through either high temperature wave soldering processes or oven based curing used in the finished component filled PCB assemblies.

“With a melting point of 217°C, SAC solder also is closest in melting point to the conventional lead–tin solder. This does mean, however, a yet-unquantified increase in energy use. Furthermore, the higher temperature may pose problems for the electronics industry. Higher temperatures mean more stress on components and the entire manufacturing process, notes Geibig. Higher temperatures also mean increases in the time it takes to make products, because more time is required to heat and cool the products during the course of their manufacture.” [2]

On July 1, 2006 the European Union Waste Electrical and Electronic Equipment Directive (WEEE) and Restriction of Hazardous Substances Directive (RoHS) came into effect, prohibiting the intentional addition of lead to most consumer electronics produced in the EU. California recently adopted a RoHS law and China has a version as well. [3] In order to meet the new directives established by the EU on removing the lead from electronics, has greatly affected the PCB assembly world at large. In effect, countries that did not have directives for the use of lead-free electronics assembly, were forced by default of having to build to meet the international requirements from the EU.

“This directive (EU Directive 2002/95/EC) places a restriction on the use of certain hazardous substances in electrical or electronic equipment sold or used in the European Union (EU) after July 1, 2006 with some exemptions.” [4]

‘Within the United States, California’s Electronic Waste Recycling Act imposes a fee on “covered electronic devices” currently being sold within the state. This fee is intended to cover the cost of properly disposing of the products when they become waste. Second, it requires “covered electronic devices” sold in California after January 1, 2007 to meet the same requirements as those found in European Union Restriction of Hazardous Substances (RoHS) legislation. Electronic devices containing toxic metals and not complying may not be manufactured, sold, or imported into California after January 1, 2007.’ [4] Other states have enacted similar laws.

So, what does that mean for circuit board and electronics repair folks today looking for ways to extend the service lives of their equipment? Well, there are some special soldering techniques that are involved to do the electronic repair jobs right.

What is required to repair lead-free circuit boards with large discrete components?

These lead-free soldering tips are specifically geared toward the large discrete components such as: electrolytic capacitors, transistors, diodes, bridge rectifiers, and coils (inductor chokes). Information on how to repair and replace surface mount devices with lead-free soldering techniques is waiting for a later date to be written.

1. The minimum wattage for a soldering iron needs to be 60 watts. The 60 watts rating is only part of the specification to consider. Be aware that some soldering irons actually get hotter than others given the same wattage ratings. Additionally, you will need to consider using a proper soldering tip for the job at hand. If you are trying to solder on a thick multilayer PCB, then a wide tip is absolutely required to do the job right. There is also a difference in the coatings between the lead-free tips and the old standard Pb tips used for the standard 60/40 Tin Lead (60/40 Sn/Pb) Solder. 60/40 Sn/Pb melts at 370 °F or 188 °C while various lead-free solders used in PCB assembly have a melting point range of 415-441 °F or 213-227 °C . It is important to note that the increase in the melting temperature for lead-free solder, does not tell the whole story for proper solder joints involved with component replacements and PCB repairs.

You might be thinking, that the soldering iron I will be using gets up to 850 °F, I should be able to repair any lead-free soldered component on any PCB. That is wrong thinking here. I mentioned at the beginning about having a wide tip when soldering a thick multilayer. But, you need more than a wide tip. The soldering iron, at the tip, must be able to quickly recover on the heat cycle. It must also be able to supply the heat continually at a constant temperature, or near constant temperature to do the job right. This is where the wattage of the soldering iron is a factor for delivering the heat continually.

A thick multilayer PCB acts like a huge heatsink, sucking the heat away from the area that you want it, and dissipating it over the area where it is not required. If you use a small caliber soldering iron to try and remove components on this type of PCB, you will more than likely simply heat up the circuit board in a wide area, including the component itself before the solder will ever melt. In fact, it is quite likely that the lead-free solder will never melt, because the soldering iron can not quickly and effectively localize the heat in a high enough concentration to do any good. Actually you will probably do more harm than good.

I have heard from some folks, and talking from experience, that you will end up throwing a few choice words around that will not endear yourself to your spouse, if you try to use a low powered soldering iron. Even if you do manage to remove the component, the new component you install will have either the poorest of a solder joint, making you look like an amateur, or worse, an overly heated and damaged component that will result in early failure. Solder joints made with a low wattage soldering iron will likely result in cold solder joints, which will result in poor electrical connectivity and a non-working circuit board.

How about a portable butane powered soldering iron, won’t that work better? Been there and done that. Take it from experience, the answer to that question is no. I tried a wide tipped butane powered soldering iron and I was not able to even make a dent in the lead-free solder on a Apple iMac G5 motherboard.

What about a soldering gun? Once again, been there, done that. It doesn’t work with even the highest powered soldering gun. Soldering guns are not really designed for circuit board repairs. Take it from experience, put this idea out of your mind, it won’t work.

So Jim, what do you recommend in a soldering iron? Do you recommend a lead free soldering iron or a lead free soldering station? Let me first say here, that I have recommended some soldering irons and soldering stations to folks that have written to me and asked for my advice on various Apple repairs, and I would be more than happy to recommend something if you send me an email request. I will say this, that you can get a very good one at a very decent price. You don’t have to spend hundreds of dollars on a soldering station. However, don’t make the mistake and think you can get by with the old hobby soldering iron that you have in the desk drawer. Trying to use a substandard, low wattage soldering iron for lead-free motherboard repairs will give you headaches galore.  Actually, I would like to hear more from readers of what you have used for lead free soldering.

2. What is the best way to remove the electronic component such as a electrolytic capacitor off a thick multilayer PCB once I have a good soldering iron or soldering station? I suggest you have the PCB standing up on edge, so that you can work from both sides of the circuit board. Check out the Chip Quik kit for removing the capacitors in difficult circuit boards. While heating up one leg of a radial electrolytic capacitor from the bottom, and at the same time slightly pushing the capacitor from the top, away from the leg being heated, at which time the solder starts to melt, the capacitor leg will start to move out of the hole. Do this for the other leg, alternating back and forth to each leg, and slowly work out the capacitor from the hole as the solder melts. After the capacitor is removed, a solder sucker can be used to remove a lot of the excess solder in and around the circuit pad. Using solder wick, (also referred to as desoldering wick or desoldering braid) on the thicker boards does not work well because of the extra heatsinking that occurs when the solder wick is applied. At this stage of the component replacement repair, invariably, not all the solder will come out of the holes with the use of a good quality solder sucker. This is where I suggest using my next soldering tip.

3. Try using a sewing pin, with a plastic head, (even a correct size safety pin works) and heat up the tip and the solder pad at the same time, once the caps are removed. This will push the solder out of the holes and solder will not stick to the steel sewing pins. Stop in at your local sewing machine center and you will find a large assortment of sewing pin sizes. Select a sewing pin size that matches up to the size of the leg of the capacitor. Once the pin is pushed through the hole, continue to apply heat to the pin and the pad, and move it in and out, making the hole the right size for your new components.

4. Is it best to use lead-free solder when installing the replacement capacitors? I have mixed thoughts on this. On the one hand, since the board is already using a lead-free solder, I would say stay with using lead-free solder. Yes, standard 60/40 lead solder is much easier to work with, due to its lower melting point, and some folks say it seems to work fine, but I have some reservations about using it. One negative item to be aware of here is that it is much more likely to end up getting cold solder joints when mixing solder types, and the other concern is, there may be a reduction in the soldering iron tip life if using the special plated tips designed for lead-free soldering, and using leaded solder.

I do have one major item that must be adhered to; only use a rosin core type of solder. Do not use acid flux. No acid flux. Acid core solder and acid flux will damage the circuit board and/or the components. With that being said, it is important that what ever solder is used, that the old solder and the new solder join (melt) together when installing the new components. Be careful with this that you don’t under heat or over heat your work. Just the right amount will do. It is hard to describe how much, and how long the heat should be applied to get a good solder joint. Take a close look at your solder joints. If they seem to be loose, then reapply the heat until the old and the new become one. As an additional note, and I have to say once again as a matter of importance, remember that the components themselves do not like it too hot for too long.

NC600 Lead Free Solder No_Clean Flux Core To properly solder motherboard capacitors on thick MOBs, you will need to operate the soldering iron or soldering station temperatures at or near maximum temperature settings. Heat up the pad on the bottom first and foremost by having most of the soldering tip on the pad; while at the same time having the tip touch the capacitor leg. I strongly suggest using lead free rosin core solder with a no clean residue; which you can purchase with your capacitors order at www.jwestsales.com. The no clean flux rosin core solder simply means that the center of the solder has a flux rosin core that is activated by heat, and the remaining residual flux does not need to be cleaned off the circuit board and will not harm the onboard circuitry. Remember also, that the MOB has residual lead free solder already present on the circuit pad and lining the circuit board hole walls, and must be melted (typically referred to as “wetting” action) with the new solder to form a good solder joint. If you use standard 60/40 lead solder for soldering, it is much more difficult to do the job just right, and is much more likely to produce cold solder joints because the different types of solders melt at substantially different temperatures and will not properly join together.

Be careful of other small components and surface mount devices (SMD) on the bottom and top of the boards. These devices are so small, that many times they can be damaged or unattached to the PCB simply by accidentally placing the soldering iron tip on the surface mounted component soldered leads, either moving it or bridging the leads with solder. So what I am saying is, try to use a steady hand.

The picture above, of the custom circuit board clamping hands-free support system, is the brainchild of Paul N. — Grayslake, IL. Paul writes, “You can buy a 12″ x 2.5″ (depth) wood-working clamp from Home Depot for about $10 and a 3″ ‘C’ clamp for another $5. Then apply some adhesive-backed, dense foam rubber on each face of the wood-working clamp. Note that I removed the hard rubber covers that were on the clamp originally.” Paul calls the device the, “Kludged Circuit Board Clamp.” It is important to note that when clamping the circuit board with any clamping device, that you do not position the clamps on top of any components or the very small low profile SMDs on either side of the PCB.

There is another lead free soldering/unsoldering components helper that is simply amazing! Check out the video of the Chip Quik lead-free unsoldering kit and system of replacing components on circuit boards. I highly recommend this patented SMD and discrete components removal kit.

Read more about Apple iMac G5 Motherboard and Apple Power Supply Repairs.

Feel free to contact me at anytime.

Jim Warholic

Years of experience in the electronics industry. :-)

Sources:
[1] The effects of lead-free on PCB fabrication: assemblers may bear most of the brunt of the…

[2] Getting the Lead Out of Electronics

[3] Solder: Wikipedia

[4] Why Should I Care About RoHS and Lead-Free Initiatives?

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