Electronics

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Electronics Bench
Electronics Bench
Electronics Bench in use
Electronics Bench in use

How can we help you make, test or fix your electronic or electrical device or gadget?

Our Expertise

Although we don't offer formal training in electronics, several of our members are able and willing to help with electronics design, construction and repair questions and issues.

Analog Electronics

We have a number of S66D six transistor AM (medium wave) radio kits available that are a good introduction to through-hole kit construction. They aren't great radios but when carefully constructed and properly aligned, typically work as well as most comparable '70s commercial Transistor Radio designs. Unfortunately the kit instruction leaflet is in Chinese but we do have the English instructions to refer to during construction.

Microcontrollers and SOCs

Collectively, we have experience with:

We have a few microcontroller development boards available for self-education, project prototyping and other temporary use, including a mostly complete Funduino kit (ATmega328P Arduino Uno clone) with various sensors, and various other Arduino related boards.

We have a Raspberry Pi Zero, with Raspberry Pi OS 11 (Bullseye). It boots to the command line with auto-login, so type startx for the GUI desktop. It is configured so it can be USB tethered as a RNDIS device. It is accompanied by a four port USB hub PCB with USB micro-B plug, and a 650mA power supply.

General

and experience with:

  • PCB design
  • DIY PCB making
    • Toner transfer method
    • Etching
    • Tinning
    • Solder mask (UV Exposure)
    • SMD stencil etching
however it is hard to justify making PCBs 'in house' due to the low cost, quick turnaround, and superior quality of the various far East PCB prototyping services. We do not have PCB making equipment at RML.
  • Soldering techniques

Our Electronics Equipment

Electronics Bench
Electronics Bench
Electronics Bench in use
Electronics Bench in use

Here you will find manuals and other detailed notes for the tools and test equipment in the Electronics area.

General

  • Various hand tools, test equipment, wiring, connectors, resistors, capacitors, LEDs and other assorted components
  • UV exposure box
  • Magnifying lamp
  • 'Helping Hands'
    • Two positionable clips to hold wires, components and small assemblies
    • Magnifier
  • Tiltable plastic jawed vice
    • for holding medium PCBs and small assemblies
    • Do *NOT* use for assembling IDC cables or forcing a fit - grab a drill press vice from the engineering bench for that!
  • Low profile PCB vice
    • for holding small PCBs with adjustable spring-loaded clamping fingers.

Soldering/Desoldering

  • Weller WS80 temperature controlled soldering station
  • Multicomp Pro MP740261 Soldering Station
    • Temperature controlled, 80W, 240V, 480°C Max Temp
    • User Manual and Spec. sheet
    • with Yihua stand with brass wool and sponge, and a selection of tips
    • takes Hakko 900 series tips
  • Power+ 8000 series SMD Rework Station
    • A 'knockoff' of a Yihua 852D+ - 852D+ Manual
    • Variable temperature and flow hot air tool - with set of 10 nozzles 3 mm - 12 mm round + 10 mm and 12 mm square.
    • 50W temperature controlled soldering iron - Takes Hakko 900 series tips.
      • The iron is a Yihua 907A clone, five pin GX16 connector, male on the station, female on the iron, Yihua pinout. The iron has an A1322 clone element nom. 24V 50W. Tips should be 6 - 6.5 mm OD, and nom. 4 mm ID.
N.B. Tips must be a good close fit on the ceramic element, but not excessively tight. Many clone tips are too loose and will need a sleeve to function. If the tip is too tight there is a high risk of breaking the element.
  • BGA re-balling station - YouTube demo
    • Uses same Yihua 907A type iron as the SMD rework station.
Lives on the high shelf over the wood store
N.B. the front of the holder for the gun is broken so it doesn't click into place. It will sit in the holder if you rest the handle on it with the gun pointing straight down. Make sure there are no cables or hoses (or anything really) near the barrel or tip!

Bench Power Supply

Pulse Generator

  • AIM & THURLBY THANDAR INSTRUMENTS TGP110 10Mhz Pulse Generator

Logic Probe

Lives in the bin with the Logic Analyser - see below

Oscilloscope

  • Rigol DS1104Z
    • 4 channel 50MHz Digital Oscilloscope
    • Manual

Digital Frequency Meter

Multimeters

  • Fluke 77 DMM (grey, in brown rubber bumper)
    • N.B. Rotary mode switch detent is very weak, so carefully align pointer with desired mode indication before use.
  • Fluke 77 III DMM (grey/yellow)
Please carefully check the red test lead is *NOT* plugged in the Flukes' 300mA or 10A (current) sockets before making voltage measurements, as Fluke current range fuses are expensive to replace. If you suspect the inital current in a circuit may exceed 10A, please don't grab one of the Flukes to measure it!
  • Precision Gold M285 - ex. Ian B.
    • We cant find a manual for it, but its based on a TC7106 chip so is 3 1/2 digit and approx 0.5% accuracy on DC ranges. In addition to the usual multimeter ranges, it can measure capacitance up to 20 uF, frequency to 200 KHz, transistor hFE, and with a type K thermocouple, temperature in °C and °F. Great for low voltage stuff, but as it isn't CAT rated, not recommended for use on mains circuits. 200 mA range takes a 20 mm 250 mA fuse, but the 10 A range is unfused. Spare fuse stored inside.
  • Various cheap small DMMs M-830B & similar - See Big Clive's video review/tutorial
    • CAUTION: Do *NOT* use the cheap DMMs on live mains circuits

Always check the leads are in the correct sockets before using any multimeter. When finished, please leave the leads set up for voltage measurements, and check the meter is switched off. Please report any non-working current ranges to a maintainer - although changing a fuse seems simple, we need to use the correct fuse and order a spare.

Component Tester

  • Our component Tester is a 'M8 Transistor Tester', a variant of the popular AVR Transistor Tester, developed by Markus Frejek and Karl-Heinz Kübbeler. Its in a blue 3D printed case, with a ZIF test socket and a rotary encoder to select functions. It identifies most 2 and 3 lead semiconductors, and the value of smaller capacitors and inductors, and also resistors.
Component tester connections
Component tester connections
  • Connect the part to terminals 1, 2 and 3 (or any two for two leaded parts), push the socket lever right and down to clamp the leads and click the round blue knob. It will then tell you what the part is, its parameters, and identify its leads.

PC/Mac hosted tools

All the PC/Mac hosted hardware tools live in the card bin marked LOGIC ANALYSER, on the electronics shelves at the end over the wood store.

Software

  • LTspice XVII circuit simulator is installed on the all-in-one Mac next to the electronics bench. (PC version running under WineBottler)
  • Arduino IDE (v1.8.19) is installed on the same Mac.

Logic Analyser

  • An eight channel USB logic analyser (Salae Logic 8 clone) is available, and the Sigrok software for it installed on the Mac.
    • It is for 2.4V to 5V logic levels though the input protection circuit can handle moderate transient over and under voltage up to +/-15V on a single input. Gnd is connected to host PC ground - beware of ground loops or logic ground not at mains PE earth potential. CLK is *NOT* an input, it is a clock output, typ. 12MHz but that depends on the firmware loaded.
    • There are some M-F and F-F duPont wires with it, and also six F duPont to mini-grabber wires.
    • File:Pulseview Logic 8.zip - Session setup files to match the channel labels on the logic analyser pod, and either a 'rainbow' ribbon cable or the mini-grabber colours, assuming black is Gnd.
  • Troubleshooting: In Pulseview, make sure the 'Salae Logic' device is selected. If not present, in the 'Connect to Device dialog, select the 'fx2lafw' driver, and USB interface. Logic 8 clones are generally fussy about the quality of their USB cable. If it is detected by Pulseview but acquisition (silently) fails try a different cable (USB A to mini-B) direct to a host USB port, not via a hub or extension cable. The Pulseview error log can be found in its Settings dialog (crossed screwdriver and wrench icon).
  • Installation: Under Windows, Pulseview requires Microsoft Visual C++ 2010 Redistributable (SP1 MFC security update 5/12/2021). Visual C++ 2013 upwards redistributables don't contain the required DLLs.

PIC & AVR Programming

  • A PICkit 2 is available for programming older Microchip PICs and Atmel AVRs, with two short grey cables (with black header shells) for target boards: 6 pin SIL M-F cable for 0.1" pitch PIC ICSP headers, and 6 pin SIL M to 2x3 pin F cable for AVR ISP 2x3 headers. Also there is an 18 cm programming cable for PIC and AVR devices on a solderless breadboard - 6 pin SIL M to individual colour coded wires with pins.
  • An USBasp is available for programming Atmel AVRs, with 10 pin Atmel ISP cable, and 10 to 6 pin adapter. Its a 'bare board' programmer in the small flat cardboard box.

Wire

We keep a small quantity of coloured thin stranded hookup wire, and also 30 AWG solid core 'bodge' wire in stock for general use. If you need a lot of wire, or heavier gauge, or specialist cables, you will need to supply it yourself.

Beware of counterfeit wire!

Fake copper wire has become an increasing problem in recent years. Here's what BASEC have to say about the issue: https://www.basec.org.uk/resources/counterfeit-cable/

As makers and electronics technicians, we are most likely to encounter fake copper wire in smaller gauges. The three most common types of fake copper wire we are likely to encounter are:

  • Insulated wire and cable with significantly smaller copper conductor CSA (cross section area) than the minimum required for that wire gauge, which results in a higher resistance, with the possibility of overheating and even fire if you pass high currents through it. You'll spot this as soon as you strip the end of the wire, but it can catch you out if re-using mains leads with moulded on UK plug to C13 ends.
  • CCS (copper clad steel) wire. Its far stiffer than copper wire of the same CSA, has much higher resistance, poorer fatigue resistance, and will damage wire cutters not rated for cutting mild steel wire. However at least its easy to spot as it is noticeably magnetic, and a small strong magnet will be attracted to it even through the insulation and outer jacket of cables. CCS wire may be legitimately used as the centre conductor of some types of high frequency coaxial cable, as the RF current only flows in the copper layer due to the skin effect, so the steel core doesn't matter electrically, and the higher tensile strength of steel is desirable. *PLEASE* don't use the electronics bench good small side cutters on CCS wire!
  • CCA (copper coated aluminium). It has higher resistance and much poorer fatigue resistance. This one is much harder to spot, especially if tin plated. For larger diameters of solid wire, you can see the freshly cut end is silvery rather than copper coloured, (or you can deeply scrape the side with a knife and see the same) and the weight per unit length will be lower than comparable copper wire. The easiest way of detecting smaller diameter CCA is by doing a flame test. Strip about 3 to 5 cm, untwist stranded wire and hold it in a lighter flame - small diameter copper wire will withstand the flame with brief exposure up to red heat resulting in only moderate discolouration and oxidisation. whereas CCA will rapidly 'flop' where the flame heats it and discolour severely: https://www.youtube.com/watch?v=rL5VUYe_uX8

Other wire info

  • Aluminium magnet wire is legitimately used in low cost appliance motors and power transformers, usually in low duty cycle applications. Its difficult to make a reliable electrical connection to it, near-impossible to solder, and the original termination is likely to be a crimp or spot weld. It tends to fail at the terminations in notably damp environments due to electrolytic corrosion.
  • Stranded electrical wire (with plain bundled strands i.e. not rope laid) has a CSA of approximately 90% of that of solid wire of the same overall conductor diameter due to the tiny voids between its close packed strands. For an accurate CSA measurement, it is not sufficient to calculate it from the overall diameter, as that is increased by twist, and also by possible gaps in the surface layer of strands, so you have to use a micrometer to measure the diameter of sufficient undamaged individual strands to get a good average, calculate the CSA of an individual strand, then multiply by the strand count. This is a PITA and is best avoided unless you need to verify that a wire meets specification.

Tutorials and links

Soldering

Over forty years ago PACE released a series of training films to the electronics industry. More recently PACE re-released them on Youtube.

  • PACE Rework and Repair (Lessons 1-8) - You've found the fault, but the PCB itself is damaged or you are unsure how to tackle replacing a component. Watch this series and learn how far the professionals can go to save a high-value board!

Youtuber Dave Jones (EEVblog) has done several soldering tutorial videos.

  • EEVblog #181 - Dead Bug Prototype Soldering - How to solder a small 3 axis accelerometer LGA surface mount chip “dead bug” style onto a microcontroller prototyping board
  • EEVblog #346 - MLF/QFN SMD Reflow Soldering - How to use solder paste and a hot air gun to reflow solder a surface mount SMD 0.5mm pitch 3mm x 3mm MLF (QFN) chip
  • EEVblog #434 - SMD Thermal Pad & Drag Soldering Tutorial - Another method for hand soldering a surface mount SMD chip with a thermal pad, using both liquid and gel flux. Also drag soldering a TSSOP
  • EEVblog #688 - How To Rework Solder SMD Chips - Replacing a blown SSOP surface mount chip with ChipQuik, solder wick, and drag soldering
  • EEVblog #782 – The Dangers Of Reflow Soldering - Reflow soldering in a DIY oven can be tricky business for connectors and other parts, particularly ones designed only for through-hole soldering.
  • EEVblog #1064 - Soldering Irons OLD vs NEW - What are the differences between the “old” style soldering iron tips like used on the low cost Hakko and Weller et.al low cost irons, and the more expensive integrated tip type?
    • EEVblog #1065 – Soldering Iron Power Delivery Explained - Follow-up to previous video, + the differences between applied power, tip design, sensor design, control loop design, and power delivery to a ground plane.
  • EEVblog #1113 - Is a $5 USB Soldering Iron Useful?
  • NASA Workmanship Standards - A 'must read' if that soldered (or crimped) joint is mission or safety critical. Most of us will never need to apply them in full, but its good to know what 'best practice' is.
  • Solder alloys - Wikipedia's list of solder alloys, their melting points and typical uses. Searchable e.g. try Ctrl-F Sn60Pb40

Building Prototype Circuits

  • The Lost Art of Strip Board Prototyping - Nuts & Volts Magazine - How to build prototypes with through-hole components on stripboard. Design, layout and construction considerations + hints & tips.
  • VeeCAD - CAD software for laying out circuits on stripboard, matrix board, and other types of perf board + solderless breadboards. FOSS, WinXP - Win10+ or Wine on Linux.

Identifying parts

Test Equipment

Oscilloscope

Repairing stuff

  • Sci.Electronics.Repair FAQ - "This site features Samuel M. Goldwasser's latest and greatest "Notes on the Troubleshooting and Repair of..." series of comprehensive repair guides for consumer electronics equipment and other household devices. There is also a great deal of other information of interest to the electronics hobbyist, experimenter, technician, engineer, and possibly even the dentist and poet. Included are the now quite comprehensive and massive "Sam's Laser FAQ", many new schematics, and links to over 1,000 technology related sites. In addition, there are a variety of documents from other sources on electronics troubleshooting, repair, and other related topics."

Electronics Forums

EEVblog Forum - run by electronics Youtuber Dave Jones - A good place to ask any electronics related questions, with a far wider pool of friendly experts than we can muster at RML

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