Repair of Samsung LE40M86BD Television (power cycling)

Samsung TV

Introduction Recently I have had cause for complaint with our Samsung LE40M86BD LCD Television.  It had been working just fine, and then all of a sudden it developed a power-cycling problem.  The symptom is as follows: From power-on, the TV works perfectly for around 10 minutes. After a while the TV switches itself to standby,… Continue reading Repair of Samsung LE40M86BD Television (power cycling)

Sorting out the Velleman MK170 Christmas Star

Star After Mods

Last Christmas I bought a Velleman MK170 Christmas Star project for my Wife to build.  She often shows interest in my various electronics projects and I thought it would be a good way for her to build something that she could show off to friends and family, whilst at the same time teaching her a… Continue reading Sorting out the Velleman MK170 Christmas Star

Simple circuit for controlling LED brightness

The LED Dimmer Pack

Recently I was asked to produce a circuit to create a variable ‘dim’ control for an existing LED based exhibition. I decided to go with a simple 555-timer based design which provides control of the pulse width of an output, whilst keeping the oscillation frequency fixed. The circuit is shown below.  It’s an unusual design,… Continue reading Simple circuit for controlling LED brightness

Install Freerouting on Ubuntu 14.04 – 16.04

Introduction Freerouting was a web application created and maintained by Alfons Wirtz at his website, here.  It allowed us to import a design file from kicad and then auto-route the project based on some design preferences.  It was basically a free auto-router for kicad.  Hence the name! For “various reasons” the author has decided to… Continue reading Install Freerouting on Ubuntu 14.04 – 16.04

Panasonic AE700 Projector Diagnosis & Repair

Panasonic AE700

In the tinkering cave this week we have a Panasonic AE700 HD Projector. These units are pretty old now, but they come highly recommended in many online reviews and the HDMI support means they remain a useful home cinema option. The unit was first presented to me by a work colleague who complained that the… Continue reading Panasonic AE700 Projector Diagnosis & Repair

Installing daily build of KiCAD [Ubuntu]

I noticed, recently, that KiCAD footprint libraries now carry the .pretty extension, and that these files cannot be read by the latest stable release of KiCAD.  In order to make use of these libraries it is necessary to install a recent build of KiCAD, which has undergone a significant overhaul of its footprint library support.… Continue reading Installing daily build of KiCAD [Ubuntu]

Resolving duplicate part name problems in KiCAD

The Problem In KiCAD, a problem occurs when you try to create a new schematic symbol for a custom library and you happen to give it the same name as another part that exists in a different library. For example, let’s say you decide to create a part called “MAX3232”, and there happens to be… Continue reading Resolving duplicate part name problems in KiCAD

Hardware Hacking the IOMEGA StorCenter ix2-200

Introduction The StorCenter ix2-200 is a RAID network drive supplied by iomega.  I have used the 2TB version for about two years now to keep secure (backed up) copies of my precious data.  Any data I write to the device is mirrored on its paired 2TB drive inside the unit, so one drive can fail… Continue reading Hardware Hacking the IOMEGA StorCenter ix2-200

Digital Multimeter Accuracy Explained

Introduction The digital multimeter is the most widely used test instrument in the electronics industry.  It is the standard tool for electronics Technicians and it’s usually the first test/diagnosis tool that a newcomer to electronics will purchase. Despite this, multimeter capabilities and especially the concepts of multimeter accuracy are often misunderstood or ignored.  I have… Continue reading Digital Multimeter Accuracy Explained

Agilent U1253B Input Impedance Problem

Measuring the Agilent's Single Display Input Impedance Using the Insulation Tester

 Gotcha! I’ve experienced a problem recently whilst measuring high voltages with a 1000:1 high voltage probe and an Agilent (U1253B)/Fluke (28II) multimeter.  The problem is that the two meters don’t agree with each other! The Fluke (my meter of choice) returns voltage readings within expectation all the way up to 12kV (12V as displayed on… Continue reading Agilent U1253B Input Impedance Problem

The “Repair Man” Trap

Image obtained from http://bcths.net/

Anyone who has ever worked in the electronics trade will almost certainly have been asked to repair consumer electronics products for friends, family and even random neighbours.  How do you deal with these requests? Do you politely decline or do you end up getting sucked in? Rookies usually get sucked in.  I’ve been there, done… Continue reading The “Repair Man” Trap

RC5 Decoder

The finished RC5 Decoder in action

Introduction I completed this design a number of years ago when I was still learning to program.  In fact, this was my first “proper” project that I directed my new-found programming skills towards.  My programming skills have improved by many orders of magnitude since, and with that in mind I was a bit ambivalent about… Continue reading RC5 Decoder