Category: Electronics

Explorations in things electronic

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Dead monitor

The monitor finally gave up the ghost. It powers on, but no backlight. Fortunately there’s a spare monitor, but I’ll need to scrounge up a VGA/DVI cable or find an adapter (think I’ve got one somewhere). It’s a smaller monitor, but it will do for now.

I think I’ll take this monitor out to the bench and poke around inside to see if I can find anything easily repairable. A bit of Googling suggests the primary culprit is some bad capacitors on the power supply side of things, which should make it a repair well within my skill range.

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Fluke 75 DMM repair

I think my skills at the workbench have progressed to the point where I’m feeling pretty good about being able to make minor repairs to some of my electronic gadgets.

I’ve had this Fluke 75 autoranging DMM sitting in a toolbox for a bunch of years because it never worked properly. Brought it out to the workbench the morning and cracked it open to find the 9V battery inside had leaked, and the battery posts had corroded.

Fluke 75 digital multimeter

Should be a pretty easy fix. I’ve got some 9V battery connectors with leads in the parts bin. Heated up the soldering iron and removed the old posts, then soldered in the leads for the 9V connector. The original battery posts had three connections, so I used some hookup wire to jumper the other two connections to where the connector leads were going to go.

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Radio Shack deals for builders/makers

If you happen to be near your neighbourhood Radio Shack, stop in and you might find some good clearance deals. Look for the items with blue or tan on the price tags.

I stopped in today to look for an audio transformer to build a sound card interface for the radio, and ended up coming out with a couple pieces of 4.5×6″ perfboard, a resistor component pack, and a capacitor component pack that were on clearance. The perfboard was less than $1.50 each, and the resistor and capacitor component packs were $7 and $6 respectively. The component packs are normally in the $25 range I think. Although I’ve already got plenty of resistors and capacitors, it was really the boxes that I wanted. I think of it as a two good component boxes that come with free resistors/capacitors.

My store also had a few Arduino shields that were clearance marked as well.

Might have to pay a visit to some of the other Radio Shacks in the area.

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More workbench gear and parts

Thanks to Jason/NT7S for enabling my growing homebrew electronics ambitions. I now have a bunch of stuff to add to the workbench.

There’s this big bag-o-parts to augment the parts bin. It’s filled with resitsors, capacitors, diodes, transistors, inductors, ICs and crystals.

A bag of capacitors, resistors, diodes, transistors, inductors, crystals, and integrated circuits

He also sent along a first version of his HF return-loss bridge kit and an M3 frequency counter/power meter for the workbench. With the return-loss bridge, frequency counter/power meter, a signal generator and oscilloscope, Jason tells me I’ll be able to make all kinds of measurements for testing and characterizing circuits. I guess I’ll need to spend some more time with the Heathkit signal generator to see how operational it is. I’ll also need to pick up some BNC connectors and jumper cables.

Jason also recently acquired a couple of TI Tiva Launchpad boards, so I got his surplus TI Stellaris LM4F120 and MSP430 boards to play with. Not quite sure what I’ll do with them yet, but maybe they’ll push me to brush the cobwebs off the C I’ve learned.

I also received most of the components I’ll need to build some version of a sound card interface that I can use to connect to the radio for using digital radio modes. I think I’m going to have fun working on that project.

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From breadboard to Perma-Proto board

First I took the little Morse code kit and put it onto a breadboard. Over at adafruit.com, they have these neat Perma-Proto PCBs that are circuit board versions of a breadboard. Makes it easy to transfer something you’ve assembled on a breadboard to something a little more permanent.

I picked up a few a little while ago with the intention of transferring the breadboard version of the Morse code kit to a Perma-Proto board and finally got around to it this evening.

DSC00703.JPG

DSC00704.JPG

It turned out pretty compact and can be powered by a 9V battery, or three CR2032 button cells (shown). The clicky button still isn’t great for tapping out Morse code, but it mostly works.

A nice relaxing couple of hours spent melting some solder.