Testing & Fault Finding Of Products & Designs
Reliability In Design
Without the basic knowledge of electronic engineering, reliability of product design can not be achieved, I am able to repair and fault find down to component level, many engineers in the field today only board change. Everything I know and understand in electronics today started for me at a very young age. At the age of 10 I was being taught after school each night by my Father on the basics of electrical and electronic design and engineering, he was the head engineer of 2 major hospitals in the area and knew a thing or two! For me as a young enthusiastic person, it entailed learning resistor colour codes, building Maplin Electronic Kits, Velman Kits etc and leaning about components and how they worked, circuit design and being able to read circuit diagrams.
Those early learning years were so valuable to me and taught me so many important factors in electronics and design theory. Now allowing me off companies the most professional complete array of electronic design services that are required for designing reliable, stable products. I also gained a wealth of knowledge years ago working for companies such as Marconi Electronics (Chelmsford, Essex), Gould Electronic (Hainault, Essex), STC Electronics (Basildon, Essex), ANC Electronic (Loughton, Essex).
Below you can view images showing my ‘hand on’ workshop time and electronic knowledge in servicing a range of professional audio power amplifiers and powered mixers made by German manufacture Dynacord & Peavey, this involved some major rebuilding and repairs.
Theory In Design
Products you know, use and love don’t just work by magic, hours and hours of research, testing time & development by engineers have been spent to ensure reliability, functionality and long life. Important factors for electronic design are, Component Choice / Manufacture, Component Quality & Grade, Tolerances, thus ensuring components are not working to close to their specification limits.
Electrolytic capacitors are one of the biggest culprits of product failure, when the electrolyte inside the capacitor drys out over so many years. Choosing high quality low ERS electrolytic capacitors is always a good move when I design. Some of the advantages of low ESR aluminum electrolytic capacitors over standard electrolytic’s are their extended life (over 5,000 hours); higher ripple current ratings (compared to standard electrolytic’s); a large variety of case sizes and load-life ratings are available; larger capacitance values and standardized packages. The most outstanding differences are the load-life, impedances (Z), and ESRs at 100 kHz. These differences are why low ESR and low impedance capacitors are used extensively in switching power supplies to maintain the performance of the power supplies. Capacitors with too high an ESR will self-heat too much and not regulate the current properly. Obviously the self-heating will also reduce the operating life of the capacitors, and the switching power supply performance and life will be reduced accordingly.
Power Supply & Cooling
One of the most important parts of any product is the Power Supply (PSU), without it the product just would not work, so good attention to detail in this area is paramount. Most problems in electronics normally revert back to the power supply, this is the area of electronics that can get warm or even hot! Power supplies often get very stressed under load condition, thus it is always good practice to design power supplies with ample head room. The main purpose of the power supply is to delivers different voltages and supply high current to the associated circuitry of a product, good smoothing, power regulation, cooling and noise reduction is also very important.
Soldering & Dry Joints
Another major problem area in electronic fault finding is poor quality soldering or dry solder joints. Dry solder joints normally occur for several reasons, 1) if the soldering or flow soldering at the time of manufacturing a product is sub standard, this can cause dry joints. 2) If the quality of the PCB is poor or the tracks and pads are tarnished, dry joints can occur through poor quality solder joints. 3) if components emit heat or even get hot! this will cause dry joints as heat will travel along the leg of the component until it reaches the solder joint. The heat from the component over a period of time will slowly dry out the solder connection and cause a dry joint. The heat from a component can also dry out other solder connections not related to the component getting hot! Thus why good cooling, heat sinking and ventilation is of paramount importance. A dry joint is basically a solder joint that has lost it’s properties to allow good conduction between the component and the PCB Pad / Track, resulting in a poor connection, higher resistance, possible arcing, and greater current flow.