My Electronic Test Equipment

Doing electronic stuff needs some basic test equipment. A multimeter is a must, and an oscilloscope can't be beaten in versatility. But during the years I've collected plenty of other instrumentation as well. Most of this equipment has been purchased used. Some have been obtained for free, being either entirely broken or somehow malfunctioning or damaged. Some have required only cosmetic work, whereas others have needed up to 50 euros worth of parts to repair (that's still not a bad price for a spectrum analyzer). Some were ok or even brand new, but were greatly improved by minor custom modifications.

My DIY electronics workbench
  • The desk was bought used and has been with me over 20 years. It is a bit worn, but sturdy as hell.
  • I added shelves to it to house all my test equipment. Threaded rods carry all the weight and allow easy adjustment as well.
  • With a good fluorescent light and an ESD mat, it's a good place to tinker. The shelves also are plenty sturdy.
  • Yet it was dirt cheap compared to a real Treston or similar workbench!
Keysight 82357B GPIB-USB adapter on a Raspberry Pi
  • To control the HPIB (a.k.a. GPIB or IEEE-488) enabled instruments, I had a junk-pile PC fitted with a Keithley KPCI-488 Interface Card that was also picked up from a junk pile. Curse modern PCs that no longer have the "legacy" PCI bus...
  • Then I found a cheap (possibly counterfeit?) Agilent/Keysight 82357B USB-GPIB host adapter from eBay, and set it up with a Raspberry Pi both to control the various instruments, but also to interface between my Siglent oscilloscope and my Agilent RF generator, enabling them to do Bode plots.
  • I made a couple of simple Python scripts to use these instruments over GPIB (or Ethernet/VXI-11 or USB/USBTMC or Serial/RS232) using PyVISA. If you think they'll help you get started, you can look at them here.
Hewlett Packard HP 54501A Digitizing Oscilloscope
Iwatsu SS-6122 Analog Oscilloscope
  • Bought used, with hard currency
  • 100 MHz bandwidth, 4 channels, triggers reliably to over 170 MHz (but does become impossible around 190 MHz).
  • Dual timebase, dual trace, impressively low jitter!
  • Cursor readout, frequency counter, everything except Tetris. (Again! Damn!)
  • An absolutely fantastic instrument!!!
  • A digital oscilloscope, with all its advantages and convenience, can only complement an analog one. It could never replace a top-notch analog scope like this one. (Just compare the number of buttons and knobs with the above digital scope!)
  • If you have the Service Manual, please let me know! (Though hopefully I will never need it.)
Siglent SDS 1104X-E Digitizing Oscilloscope
  • This one I bought brand spanking new, having decided finally to upgrade to the current millennium. HP 54501A, move over!  :)
  • 100 MHz bandwidth, 4 channels, dual 1 GSa/s or quad 0.5 GSa/s, 2×14 M or 4×7 M sample memory
  • USB and Ethernet connectivity, 1 MSa FFT, Bode plot, ... Oh, go read the spec sheet yourself!!! Still no Tetris, though...  :(
  • Modifications done: None. I have not attempted to unlock the 200 MHz bandwidth (yet), because I have no need for it. Rumor has it, the PP510 probes provided with the 100 MHz SDS1104X-E aren't too great at 200 MHz, but I do have a pair of excellent 350 MHz Iwatsu SS-082R probes that would fit the bill.
  • By using a GPIB-equipped Raspberry Pi as an interface, the Siglent will do Bode plots using my Agilent E4421B (or possibly any RF generator that understands SCPI commands) or my HP 8904A as a signal source!
  • I may give away my old HP 54501A, but I'm keeping my old analog Iwatsu!
  • Are you in need of 50Ω inline terminators? BNC tees and terminators from old 10base2 networks will work just fine!
Hewlett Packard HP 8562B Spectrum Analyzer
  • Salvaged from junk pile
  • Swept-frequency triple-superheterodyne architecture
  • Frequency range originally 1 kHz–22 GHz in five bands, now only to 2.9 GHz
  • Option for external mixer
  • Resolution bandwidth 1 MHz to 100 Hz
  • HPIB bus (Here's how to get a screenshot from the 8562B over the HPIB interface!)
  • Repairs done: Replaced broken front-end mixer with a Mini-Circuits ZX05-U742MH-S+. Currently only low-band (up to 2.9 GHz) works. Replaced missing rotary control knob with one from an old Nokia monitor.
  • Total cost: 50 eur! I've seen an identical instrument (though fully working) going for 6500 eur!
  • I need to build a tracking generator for this
Boonton 42B Analog RF Microwattmeter
  • With 41-4A detector
  • Frequency range 200 kHz–7 GHz
  • Power ranges –50 dBm...+10 dBm full-scale
  • Really nice Ye olde scientific instrument. Gotta love the pale-green Boonton front face!
  Anadex CP-700 Frequency Counter   (Removed from my lab)
  • Frequency ranges 5 Hz–100 MHz, 0.1–1.0 GHz
  • 100 / 10 / 1 Hz resolution
  • "Avionics test equipment", according to the sticker   :)
Awful head (manufacturer unknown)
  • Very, very awful, yes.
  • Extremely high quality
  • f(3dB) from 1.72 to 3.14 MHz, overrange from below 1 MHz to almost 4 MHz
  • Repairs done: Cleaning and basic calibration
  • I need to install an HPIB interface and a flappy tongue
MFJ 259B HF/VHF SWR Analyzer
  • Frequency ranges: 1.8–4, 4–10, 10–27, 27–70, 70–114, 114–170 MHz
  • Output level: Approx. +9 dBm on all ranges
  • Yes, it really is great for tuning antennas
  • With a loop of wire, it works as a dip meter (for tuning traps etc.)
  • Repairs and mods: Reattached dislocated analog meter, added rubber protector ring around power switch to avoid inadvertent switching on
RigExpert AA-1000 Antenna Analyzer
  • Frequency range from 100 kHz to 1 GHz
  • Extended frequency range with PC software
  • Numerical and graphical display of SWR or resistance and reactance
  • Smith Chart display, FFT TDR function, everything except Tetris
  • Runs on three AA-batteries (opposed to ten AAs in the MFJ 259B) with excellent battery life
  • Here's some notes about this fine instrument
  • How to update the firmware under Linux, and Why RXTX-Tuote sucks
  • Modifications done: Updated the firmware, glued some open-cell foam inside the battery compartment lid
Leader LSG-216 Standard Signal Generator
  • Obtained cheap, malfunctioning
  • Frequency ranges 0.1–30 MHz, 75–115 MHz
  • Output level –10...+99 dBuV
  • CW, AM and FM modulation
  • Internal (400/1000 Hz) or external modulation source, pilot/stereo/L/R/main/sub channels on FM
  • Repairs done: Replaced malfunctioning relays in output attenuator
Agilent E4421B ESG-A series Signal Generator
  • Bought used, with hard currency
  • Frequency range 250 kHz–3 GHz (underrange down to 100 kHz)
  • FM, phase, AM and pulse modulation, Internal generator for modulation signal; also doubles as AF function generator
  • HPIB bus, which I use to interface to my Siglent oscilloscope to do Bode plots
  • I think this is the closest I can get to an RF amplitude reference, And at least the Boonton agrees with it to a fraction of a dB.
  Advance Instruments J3 Signal Generator   (Removed from my lab)
  • Frequency range 10 Hz–100 kHz
  • Sine and square wave outputs
  • Isolated sine output
  • Nice gear-reduction frequency dial. (Or, as I was later told, a backlash-free ball bearing drive, even nicer!) Ye olde all-analog design, way cool...
  Good Will Instruments GFG-8016D Function Generator   (Removed from my lab)
  • Also sold under Instek and Elenco brand names
  • Obtained cheap, chassis made of duct tape
  • Triangle, square and sine wave outputs
  • Frequency range 0.2 Hz–2 MHz
  • Amplitude 0–10 Vpp, offset +/– 5 V to 50 ohms
  • Digital frequency counter
  • Repairs done: Rebuilt broken chassis
HP 8904A (Opt. 001) Multifunction Synthesizer
  • Sine output from DC to 600 kHz, other waveforms to 50 kHz
  • Triangle, square, ramp, sine, noise, and DC signals on four internal channels
  • Summation of internal channels to output; FM, AM, phase, DSB and pulse modulation of output using internal channels; simultaneous modulation using multiple internal channels; modulation by summed signal of multiple internal channels, tone / DTMF / digital sequences; omg this is so confusing...
  • Single-ended (ground referenced) or dual-ended (floating) output
  • HPIB bus, which I use to interface to my Siglent oscilloscope to do Bode plots
  • Repairs done: Replaced the LCD display and the RAM backup battery
Agilent HP 6632B System DC Power Supply
  • Voltage range 0–20 V
  • Adjustable current limit 0–5 A
  • Programmable overvoltage and overcurrent protection
  • HPIB bus
  • Modifications done: Custom front panel output modification
Manson EP-613 DC Power Supply
  • Voltage range 0–30 V
  • Adjustable current limit 0–2.5 A
  • Fixed 5 V and 12 V outputs at 500 mA
  • Probably the exact same device is also sold as Lion EP-613, DCSS EP-613 and Rapid PS3025
  • Modifications done: Custom modified with multi-turn potentiometers for more precise voltage and current adjustment
Fluke 8000A Digital Multimeter
  • Obtained cheap, "unknown condition"
  • 3 1/2 digit display
  • A reliable no-frills workhorse
  • Repairs done: Replaced amp-range fuse, checked calibration
Keithley 179 TRMS Digital Multimeter
  • Obtained cheap, "seems to work"
  • 4 1/2 digit display
  • True-RMS measurement
  • Same input connector is used for both voltage and current ranges—stupid!   :(
  • Repairs done: Calibration
Hewlett Packard HP 34401A Digital Multimeter
  • 6 1/2 digit display
  • Autoranging
  • True-RMS measurement
  • 4-wire resistance or voltage ratio measurement
  • Selectable front and rear connectors
  • HPIB bus
Lübcke Vario R52-260-T Variac
  • Salvaged from junk pile, perhaps unused???
  • Output voltage range: 0–260 V (for 230 V input)
  • Current rating: 2.5 A
  • Does not provide isolation   :(
  • Repairs done: Installed the naked variac in a new chassis (old PC power supply), with appropriate connectors and fuses
Muuntosähkö KL-1000T, Muuntosähkö KLM-200
Isolation Transformers
  • Rated at 1 kVA and 200 VA, respectively
  • Repairs done: Rebuilt chassis on 1 kVA unit, installed on/off switches on both units
Efratom/Datum LPRO-101, Trimble Thunderbolt Frequency standards
  • Rubidium atomic clock, 10 MHz frequency
  • GPS time standard (OEM model), 10 MHz frequency, PPS and data out
  • Repairs done: Installed both modules in a single chassis, built regulated power supplies for both.
  • I need to build a status display and PC interface for these, and eventually a distribution amplifier.
  • With a huge LED display, this might also become my radio station's UTC-clock.
USBee AX PRO logic analyzer
  • Eight channels in a USB interface
  • Works with sigrok
  • Modifications done: Exchanged the 74HC245 chip with a 74LCX245, which is 5V-tolerant
  • The furry cow is not an original accessory

Kenwood DP-71 Logic Probe

  • TTL / CMOS voltage ranges
  • Pulse detect function
  • Surprisingly useful for detecting transient signals that an older oscilloscope couldn't see (before I got my Siglent)!
MBS-9 (МБС-9) Stereo Microscope
  • Manufactured by LZOS (ЛЗОС)not by LOMO (ЛОМО), which is a common misconception
  • Very similar to the (slightly newer?) MBS-10 (МБС-10)
  • 4.8×, 8×, 16×, 32× and 56× magnifications with the standard 8× eyepieces
  • Modifications done: Homebrew LED illumination with a 3 W LED, antistatic mat over the microscope's base
Weller WD-1000T Digital Soldering Station
  • WD-1 power unit
  • WSP-81 (a.k.a. WP80) 80 W soldering pencil
  • WDH 10T "Stop&Go" safety stand
  • An assortment of LT tips
  • This replaced my old Xytronic 369 which also was excellent
With these I have even soldered the occasional 0402 SMD component (inside my UV-3R radio). Though for convenience, I prefer to design my own circuits with 1206 or through-hole components. I have also considered making a reflow oven, but haven't got one yet. Really I don't have room for one either. With a wider tip, the 80 Watt soldering station is powerful enough to solder wires onto NiMH cells pretty much instantly, without overheating the cells.
Handicraft nuts—A better "helping hand"
  • An idea I once picked up in the Finnish Radioamatööri magazine—unfortunately I don't remember the author
  • Ordinary hex nuts—large ones—are much better than the ubiquitous "helping hand"
  • And cheaper!
PIC programmers
  • One usbpicprog device
  • One PICkit2 from Microchip
  • One PICkit3 from Microchip, which apparently is a debugger also
They all work, as did the JDM programmer I started with. Here's some notes on them. I also wrote a command line thing for the PICkit3 under Linux, using the Microchip mdb.sh utility.
Modified Uni-T UT203 current clamp
  • Very cheap, with 40 A and 400 A current ranges, AC and DC
  • Digital display for readings, but no analog output
  • Modifications done: Added an analog output that can be connected to an oscilloscope
Other multimeters etc.
  • I have a bunch of cheap no-name multimeters as well. They're not fancy, and have "only" 3 1/2 digits, but the oldest one (25+ years now) is still working, and accurate almost to one digit. The cheapest one cost 2 eur on sale brand new. There's no reason not to have a multimeter in every single tool box, radio bag and other go-kit. You always end up needing one whatever you do and wherever you are!
  • The Owon OW16A and OW18A are fine "3 5/6 digit" handheld multimeters (display reads up to 5999 instead of 1999, which is "3 1/2 digits"), one of which I keep within arm's reach at all times. They have auto ranging, true-RMS, capacitance and frequency measurement, thermocouple temperature readout, backlighted display etc, even non-contact mains voltage sensing as a bonus!
  • The UNI-T TU320D is a simple two-channel thermometer for K-type or J-type thermocouples, with a range of −50°C to +1300°C. I initially got it for calibration of my electric smoker (I did not have the Owon yet).
  • There's also an ultra cheap "Aliexpress grade" component tester, an LCR-T4 or a Mega328 or some such (it calls itself "MTester" upon powering up). It's not bad for what it is (an MCU, an LCD, and very little else—the firmware source code might be interesting to peruse, though... wait, have these originally been born out of an open source project?), and easily good enough to check what color an LED is, or if a BJT or MOSFET is working or not, or to identify the pins on a mystery transistor.
Scales — Not so much electronic test equipment, but I have a couple of them in my lab
  • Mettler Toledo PM100 (110 g / 1 mg), part of a Mettler Toledo LP16 infrared dryer / moisture analysis system. Both the scale and the dryer seem to have serial data interfaces, which I have not tested. In fact, I haven't even tested the whole dryer thing yet—I bought this thing at an online auction just for the scale, which is true lab grade and worth way more than I paid for the whole system.
  • Tomopol P800 (800/0.1 g), P600 (600/0.1 g) and P60 (60/0.01 g): Very cheap eBay scales, and quite good for their price, as long as using relatively fresh batteries.
  • OBH Nordica 9860 kitchen scale (5 kg / 1 g) for heavier stuff
Various Chemicals needed for everyday repairs:
  • Solvents
  • Contact sprays, cold spray etc.
  • Lubricants
  • Glues
  • Various other smelly things

What's still missing? A vector network analyzer would be nice (though I don't know what I'd do with it; play with it, I suppose). Perhaps an arbitrary signal generator (ditto). Maybe one more power supply with dual adjustable outputs. And a cesium atomic clock would be cool. Got any extra ones you don't want?

Antti J. Niskanen <uuki@iki.fi>