An EMC troubleshooting kit - part 5 (summary & parts list)
This is the last entry of the description of my EMC troubleshooting kit. In this last installment, I’d like to summarize what we’ve covered and follow up with a complete listing of the contents, including the components used to implement fixes. I’ve also included a couple photos of some gear not shown before. For those who may be just starting to collect the equipment and components for their own troubleshooting kit, I broke out the suggested contents into phases; “Basic Kit” and “Add-Ons & Upgrades”. If funding is not limited, then by all means, “go for the gusto”. I hope this information is useful; both for independent and in-house EMC consultants. The heart of any EMC troubleshooting kit is a spectrum analyzer, so your cost for the kit will largely be determined by the analyzer you’re able to procure. Let’s discuss this issue first.
Figure 1 - Here’s the troubleshooting kit I used to use while working for Agilent Technologies. I use a very similar kit today for my consulting business.
Choosing a Spectrum Analyzer - The one piece of gear that’s essential for EMC troubleshooting is a spectrum analyzer. You can buy a decent portable for about $10k or used ones go for $1k to $5k if you don’t mind the 30 to 80 pounds of weight or the initial investment. What’s interesting is that I’ve run into a very low cost spectrum analyzer solution called the RF Explorer, designed by engineer Ariel Rocholl, from Spain and manufactured by www.seeedstudio.com, a Chinese electronics supplier for the hobbyist crowd. The currently available RF Explorer (Model WSUB1G) is limilted to a frequency range of 240 to 960 MHz, which covers quite a bit of the most desired radiated emissions band. However, it sells for just $129, which will at least give you some idea of the emissions profile of a a product under test. I’ve used this with the Beehive probes and it works well for general troubleshooting. They also sell the WSUB1G with added Wi-Fi receiver module, called the RF Explorer - ISM Combo, for $175. Here’s some great news for later this summer. Rochell has nearly completed a brand new design for a low-cost RF Explorer (Model WSUB3G) that will be available soon for $269 and tune from 15 MHz to 2.7 GHz. With DIY probes, as I’ve described earlier, and scavenging through your local hardware store, you should be able to put together a “starting out” kit for under $200 ($350, for the upgraded RF Explorer, due out later this summer). I reviewed the current RF Explorer here…
Figure 2 - Here’s the “RF Explorer - ISM Combo”, a handheld spectrum analyzer that sells for $175 and covers 240-960 MHz and the Wi-Fi bands.
You’ll eventually want to upgrade (or start with) a better quality analyzer. I’ve been using the Thurlby Thander (TTi) PSA2701T (1 to 2700 MHz handheld, at $2k) for several years now. Many other independent consultants are also using this one. It’s truly handheld and will fit into the recommended transit case. There’s another recently announced analyzer that looks very promising and is roughly the same cost as the TTi. Rigol, a test & measurement company based in China, announced the Model DSA815TG (9 kHz to 1.5 GHz portable ($1.5k with EMI option at an additional $600). I’ll be reviewing this in a few weeks. Either analyzer should do well for you, but my preference remains the TTi because it’s fast to use and fits so well into the transit case, avoiding my carrying a second piece of gear. The advantage of the Rigol analyzer is that is more accurate and includes a preamp, tracking generator, the EMI bandwidths and quasi-peak detector. However, for that price, it’s limited to just 1.5 GHz. The tracking generator is also a valuable troubleshooting tool for determining resonances and filter responses. Of course, Rigol has models that go higher in frequency (3 GHz) for a higher cost ($6k and up with options). I’ve also noted recently there are several low-cost analog spectrum analyzers available, but I’ve also heard reports of poor reliability for many of these. Also, they will lack the means for saving instrument setups, screen captures and the like.
Troubleshooting Kit Contents - I’ve split the list of items into two groups. Phase 1 includes the essentials, or a basic kit. This gear will get you started and should easily fit into one of the Pelican transit cases. I used their Model 1514 roller case (a Model 1510 case with padded dividers, ~$200), an idea I got from my colleague, Doug Smith. I also added the lid organizer, Model 1519 (~$30) for holding cables, small hand tools, and miscellaneous accessories. Phase 1 is really the minimum I’d recommend for serious EMC troubleshooting and should cost as little as $350 with the RF Explorer. Phase 2 is a list of recommended upgrades and add-ons that will prove useful, if the budget accommodates. You’ll eventually want one of the better spectrum analyzers, a set of commercial near-field probes and a commercial current probe. A more fully-equipped kit should run you about $3k to $4k with one of the better analyzers.
Phase 1 (Basic Kit) - This kit will give you a start at the lowest possible cost, depending on the analyzer chosen. Here is a listing of the remaining contents.
- Wideband 20 to 3,000 MHz preamplifier (Mini Circuits ZX60-3018G-S or equiv., ~$50)
- Digital Multimeter (I use one of the small $5 models)
- Family Radio Service (FRS radio for radiated immunity testing, ~$30/pair)
- AM/FM radio for detecting ESD and harmonics
- UHF “bowtie” TV antenna (~$10)
- VHF “rabbit ears” TV antenna (~$10)
- Piezoelectric BBQ starter (for simulating ESD events, ~$6)
- ZipLok® bag with a few coins (for generating ESD)
- Small driver kit (with an assortment of bits)
- Various hand tools
- Power screwdriver, such as the Ryobi Model HP53L (a big help when EUT access requires undoing 30 fasteners!, ~$30)
- SMA connector wrench
- Pencil soldering iron (Weller WM120, ~$40)
- Solder and solder-wick
- Dental inspection mirror (small mirror with long thin handle for probing in confined spots)
- small flashlight
- Small magnifier
- ESD wrist strap
- Tape measure (English/metric)
- Wire (miscellaneous sizes and lengths)
- DIY H-field and E-filed probes
- DIY current probe
- 10 and 20dB attenuators (Mini-Circuits VAT-10W2, VAT-20W2 and HAT-10+, HAT-20+, ~$12 and ~$9, respectively, in SMA or BNC sizes)
- Various coaxial adapters
- Aluminum foil (1-2 foot square pieces folded)
- Copper tape (or “snail tape”, cheap, but not as good as EMI-rated tape, available from hardware/gardening stores)
- Insulating Kapton® tape
- EMI gaskets (ask manufacturers for a sample kit)
- Ferrite chokes (chip and leaded beads, clamp-on chokes, ask for a sample kit)
- Capacitors (various values, chip and leaded, in range of values: 100 pF, 1/10/100 nF, i/10 uF)
- Resistors (various values, chip and leaded in range of values: 1/10/27/47/100/470/1k/10k/100k Ohms)
- Inductors (various values, chip and leaded in range of values: 1/10/100/1000 uH)
- Common-mode chokes (chip and leaded, ask for sample kit)
- External line filter with short line plug (used in-between line cord and product)
- Small (bare) copper clad PC board (used for shield – place in Ziplok® bag for insulation)
- Clip leads (1m long)
- Various 1m long I/O cables (USB, RS-232, Video VGA, etc.)
- Various coaxial cables
Phase 2 (Add-Ons & Upgrades) - As you’re able, you’ll probably want to upgrade some of the major pieces of equipment and probes. Here’s what I recommend (or try to find something equivalent).
- Thurlby Thander (TTi) PSA2701T spectrum analyzer (~$2k from Newark Electronics or Saelig Electronics)
- Rigol PSA815TG (with EMI option) spectrum analyzer (~$1.8k from Rigol distributor or www.amazon.com)
- Beehive near-field probe set at $295. You’ll also want to order their cable and adapter kit (SMA or BNC), as the probes use an SMB connector.
- Beehive wideband (150 kHz to 6 GHz) preamp Model 150A, or equiv. (~$525)
- Current probe (Fischer Custom Communications Model F-33-1, or equiv. (10 kHz to 250 MHz, ~$1.2k)
- DIY ESD detector (see schematic in Part 3 or article here…)
- Credence Technologies ESD Aware (Model CTC34), or equiv. (~$1k)
- ESD simulator, such as KeyTek MiniZap (~$15k)
- Digitizing oscilloscope (minimum of 500 MHz bandwidth and 4GSa/s, ~$5 to 15k). I use an Agilent DSO6054A.
- Qty 2 - oscilloscope probes (10:1, 500 MHz, min, ~1k each)
- Smart Tweezers RLC meter, Model ST5, for identifying unmarked surface-mount (and leaded) components (~$387).
Figure 3 - Smart Tweezers is a small RLC meter that’s very handy for identifying small components, particularly, surface-mount parts.
In summary, this series has described the EMC troubleshooting kit I used to use while working for HP and Agilent technologies, and I assembled a like set of gear once I set out as an independent consultant. The kit has traveled with me all over the world. While the Pelican 1514 roller case is designed to fit in an overhead bin, I suspect you’d be delayed a great deal if attempting to carry it on. Therefore, I simply lock it up with TSA-approved locks check it through. I do include a note inside addressed to “TSA/Security” explaining basically that the kit is used for electronics troubleshooting and educational seminars. So far, there’s never been an issue…although, there was that time I was trying to catch a flight from Penang, Malaysia back to Singapore and the security guys eyes opened pretty wide as the case slide through their x-ray machine! After politely asking me to open it up, I explained calmly I used the stuff to help teach their engineers and they seemed satisfied.
I hope this series of postings has helped start you thinking about assembling and using your own troubleshooting kit. If you feel there’s anything I missed, please add your reply below.