Category: Electronics Blog

  • Repair of Samsung LE40M86BD Television (power cycling)

    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, […]

  • Sorting out the Velleman MK170 Christmas Star

    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 […]

  • Simple circuit for controlling LED brightness

    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, […]

  • Happy Valentines Day Project

    Happy Valentines Day! A few years ago I created a little valentines day project, shown in the video at the end of this post.  It’s basically just a multi-vibrator circuit with two groups of LEDs, arranged as an inner and outer heart: The full schematic is shown here, click on it for a full enlarged […]

  • Panasonic AE700 Projector Diagnosis & Repair

    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 […]

  • JVC TH-S5 Diagnosis and Repair

    Symptoms I’ve owned the JVC TH-S5 home theatre system for many years.  It could be as much as 8 or 9 years.  In all that time it’s been a reliable machine, although to be fair it’s also had quite an easy life; I don’t watch much TV (what self-respecting Engineer and tinkerer has time for […]

  • 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 […]

  • 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 […]

  • Agilent U1253B Input Impedance Problem

     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 the […]

  • The “Repair Man” Trap

    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 […]