Electronics Repair Work and Soldering

Lately there has been much discussion about and visibility of electronics, electronics repair, and soldering/microsoldering. I want to shed some light onto the tools and techniques to answer many of the common questions out there. This won’t be an all-encompassing guide, but will evolve and grow over time.

You’re going to need some tools and many of these tools can be quite expensive. To reduce the costs a bit, don’t run out a buy all of the new tools as you may not like some and may not need others; it is much better to work for a while a see what you need and how you work (I found although I bought an iSlack opening tools, I really don’t like it or use it).

The Basics:
Soldering:
I advocate buying used tools when possible and practical (I opted to buy used soldering and hot air stations and upgrade later rather than buying cheap clones or new name-brand). Obviously, don’t buy used consumable tools (tweezers, driver bits, etc) or equipment without making sure it is a good enough deal to be worth the risk. I also advocate buying good quality tools – buy the best you can afford and buy it once. I bought a used Hakko 936 soldering station after looking at all of new offerings and the clones. I preferred the temperature adjustment knob over the digital interfaces and I didn’t want to get a clone of questionable quality for nearly the same price. Fortunately, most of the parts are available still and replacement tips are plentiful. I also purchased a used Hakko 850 hot air station after considering Quick, Aoyue, Atten, and many other stations including new Weller, Hakko, Metcal, and JBC. I was into a complete Hakko setup for under $200. If you can’t find a used name brand, the Hakko FX-951 and Quick 861DW are good new options. I only upgraded because I found a deal on a Hakko FM-203 and FM-2022 (plus more) for less than the price of the FM-2022. It didn’t hurt that selling the Hakko 850 paid for most of the upgrade.

Along with your soldering and hot air stations, you will also need solder, flux, soldering braid, and maybe solder paste. Skip the paste if you won’t be reballing ball grid array (BGA) devices or doing new surface mount device (SMD/SMT) work. I suggest either a 60/40 or 63/37 leaded solder. Lead free doesn’t flow as well, wet as nice, or melt as easily. Stick to a name brand like Kester and you will be just fine. I have various sizes ranging from .015” through ⅛”. For this type of work, a size between .015” and .062” should work fine.

To remove excess solder and clean pads, solder wick is needed. It is much easier than trying to use a solder sucker and cleans better. You will need this for just about any type of rework you do. Solder wick comes in various sizes but 3.5mm is a good generic width. It works much better if flux is applied as it lets the solder flow up the wick better.

Flux seems to be a personal preference item as there are numerous brands and formulas available. I, and many others, like the Amtech 559. Make sure you buy it from a reputable source as it is often fake on Amazon and Ebay. Extra flux will make your rework and clean up much easier and better as it provides cleaning action and allows the solder to flow. Additional flux usually isn’t needed if you are soldering properly with flux core solder wire.

Screw Drivers and Bits:
Screw drivers and bits is one area where you should spend more for quality and where you shouldn’t buy used unless you can thoroughly check out the tips. The iFixIt kits listed below are good quality and have a lifetime warranty on the bits – if they get damaged, iFixIt will replace them. Other high-quality options include Wiha, Wera, and Moody. You can get by with lower quality bits and drivers but you will feel the difference as they slip more and don’t fit fasteners quite right.

Consumables:
There are a lot of little things in this work. We’ve covered some above: solder, solder paste, solder wick, and flux. Others are tweezers, tip cleaners, adhesives (such as the double sided Tesa 61395), Kapton tape, gloves, wipes, and cotton swabs.

Although tweezers are expensive, they really are a consumable item. Once the tips get mangled, they just don’t work right and will need to be replaced. There are some cheaper options, but you generally get what you pay for. I have this cheap set, and they work but they are much lower quality.

Specialty Tools:
Some of the specialty tools may be required for certain tasks you need to do or may simply make the tasks easier. The iOpener kit from iFixIt is a step up from using hot air to loosen display adhesive. Another step up is the heat pad which holds the device at a constant temperature while work is being done. Sure, you can replace a screen using a hair dryer or heat gun, but it isn’t the right tool for the job and is risky, and takes more time.

 

Tool and Supplies List:

iPad Logic Board and Model Number Reference List

Here is a list of Apple iPad logic boards and corresponding models

iPad 1 820-2740
iPad 2 820-2875
iPad 2 820-3069
iPad 3 820-2996
iPad 4 820-3249
iPad Air 2 820-3633
iPad Air 2 820-4550
iPad Air 820-3508
iPad Mini 2 820-4124
iPad Mini 820-3243
iPad Charger Circuit Diagram

I’ve pieced this together from all over the place – please let me know if there are any errors or corrections.

EDS, Inc LeakSeeker 89

LeakSeeker 89 PCB

EDS, Inc LeakSeeker 89 PCB

Awhile back I was reading through a back issue of Nuts & Volts magazine and came across an ad for the LeakSeeker 89 from Electronic Design Specialists. I was intrigued by the device and searched for a place to buy one, even a used one, but they were nowhere to be found. This led me to contact Dave Miga and order a parts kit. The kit price was reasonable for not having to source parts and deal with minimum order quantities plus he is the only source for the programmed PIC microcontroller.

LeakSeeker 89 Auto-ranging Fault Locator PCB

The LeakSeeker 89 locates the exact spot on the PC board (to within a fraction of an inch) where a shorted or leaky component is bringing a power supply bus or data line to ground. It is the only locator that can locate defects from zero to 300 ohms with no loss of resolution. It can even find active shorts that a DVM won’t even show. The high GAIN mode can locate shorted components on multi-layer boards with ground planes and a power layer.

After ordering the parts, Dave emailed me the bill of materials, enclosure overlays, Gerber files to get the PCBs manufactured. Not wanting to pay the suggested $100 for 5 PCBs, I invested some effort into converting the Gerbers into standard format and getting them ready for manufacturing at a place like EasyEDA or OSH Park. EasyEDA was the cheapest and OSH Park, though high quality and quick, was expensive.

So, having the parts and PCBs arrive, I began construction. Keep in mind, there are no assembly instructions at this time. (I’ll update here if I develop some.) It took me about two hours to get a finished product minus the enclosure (I’m waiting for it to arrive).

Assembly is pretty straightforward with typical through-hole components. The only issue I had was installing the BR2 rectifier backwards since it is not obviously marked (the square pad is the + pin).

I haven’t had an opportunity to use the LeakSeeker yet, but, after some basic tests, it appears to function.

The next steps are to get the case, drill it for the LEDS, switches, and probes, then make and apply the overlays. Dave provides all of the dimensions needed to ensure a quality completed product.

Here is the finished product in a poorly labeled case:

Finished LeakSeeker 89

Finished LeakSeeker 89

 

Sources:

Parts Kit: EDS, Inc – last paragraph on the page explains how to order.
PCB: These are for sale through a few outlets. The best price will be at the Eccentric Workshop store, but they are on Tindie and eBay.
Enclosures: OKW Tenclos Pulpit 590.9 – these are imported from Italy and you must email the company to order (I worked with Jeff Duchess). If there is enough demand, I may stock these.

 

Order from OSH ParkI sell on Tindie

Market Monday: TEquipment.net

TEquipment.net has turned out to be a great supplier of electronic test equipment and tools. I ordered my oscilloscope from them and initially had some issues. Their customer service was far better than any company I have dealt with before – they reached out to me to fix the problem and followed through on it.

They carry a wide range of test equipment from a wide range of brands. They also sell 3D printers, lab equipment, various environmental testers, thermal images, and soldering equipment. I will check with them first when I pick up a power supply, soldering supplies, and other equipment.

If you are shopping for electronic test equipment, check out TEquipment.net.