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Design, build, hack....zap and repeat!

Busy, busy, busy. . .

Posted on Jun 23, 2014 | Comments Off on Busy, busy, busy. . .

Wow, it’s been 2 months since my last confession! Yes. . .busy, busy, busy. Between work and work and work, there’s barely anytime to work. Just look at this mess on my workbench. Every time I set out to clean and organize the bench, I get caught up in a software issue or a capacitor replacement or a programming problem or the washer blowing a circuit board. Like Gilda Radner so profoundly exclaimed, “It’s always something!” And this weekend is Field Day so there won’t be much organizing soon. But I pledge that I will get this straightened out within the next 30 days or I’ll have to swear again in 30 days! Oh my! Related articles Workbench v1 (ajvtech.com) Building Your WorkBench (makezine.com) How to use a desoldered capacitor? (electronics.stackexchange.com) Tracking down bad caps (ajvtech.com)   Share this:Click...

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SMD Breadboarding

Posted on Apr 10, 2014 | Comments Off on SMD Breadboarding

So I watched Dave Jones’ EEVblog #555 video – 555Timer Kit where he puts together a kit of resistors, NPN and PNP transistors that recreates the famous 555 Timer integrated circuit in a large scale. It was interesting and nostalgic because everyone starting in electronics plays with a 555. So I figured I might go down to the bench, look up a circuit and try something new. . . .especially since I’ve got some new test equipment to play with, explore and learn the circuits in a new light. So I got the breadboard out and went looking for a 555 or 556 laying around in the parts drawers. Well I did find some but they were all SMD. . . .which don’t quite fit into the breadboard. Luckily, I also found a little pouch from Schmartboard which included a SOIC to...

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Test Lead Snarl

Posted on Jan 15, 2014 | Comments Off on Test Lead Snarl

So I was putting together all the test equipment on the bench. Each piece of gear came with their own set of test leads. It wasn’t long before they began getting all snarled up. . .the BNC leads with the banana plug leads with the alligator clip leads with the adapters. Rather than wait and spend 20 bucks for a test lead holder, I dug through all my pegboard tool holders and come up with a good one. Since many of the leads were over 6 feet long, (2 to 3 meters for those outside the US) I needed to put the holders up a ways so they could hang straight. I decided to clamp a small piece of pegboard at ceiling height about 8 feet and use a few tool holders I had lying around. They’re cheap at...

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New Tech Toys Pt.2

Posted on Jan 5, 2014 | Comments Off on New Tech Toys Pt.2

On to the workbench! The holidays brought an abundance of technology which I started to describe in Part 1: Overcome with technology.  Now I’m headed down to the workbench. Since I work on mobile and desktop radios, transceivers and associated equipment, many of which use 12 – 15VDC, I got a power supply dedicated to that voltage and amperage range. And since much of that equipment just plugs into the vehicle’s cigarette lighter, I chose an MFJ-4245MV which just happens to have a cigarette lighter jack built right in! While testing the transmit side of these radios, you somtimes need to measure the output power. So I got a dummy  load / wattmeter to measure the wattage while transmitting into a 50 ohm “antenna” without going out on the air. I chose the MFJ-267 since it could handle up to...

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What’s a Gadgeteer?

Posted on Sep 6, 2013 | Comments Off on What’s a Gadgeteer?

After the Arduino came out and before the Raspberry Pi, there was a subdued hacking platform created by Microsoft called the Gadgeteer. Yes, Microsoft is, deep down, a hacking kind of company. After all, that is the way it started in the software business. And from the beginning it has always had its hands in some sort of hardware, although better known for its operating system and software. Even though there are several platforms better known to the hacking and maker communities, the Gadgeteer is rather innovative. Projects with the Gadgeteer consist of a mainboard and modules connected via a standard 10 pin connector. And although the software language is on the  Microsoft.NET Micro Framework,  it is publicly licensed under the Apache License and the hardware designs are under the Creative Commons License.  Hardware modules are available from several vendors. There...

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Is Heathkit back?

Posted on Aug 25, 2013 | Comments Off on Is Heathkit back?

So I went to a Tailgate Fest sponsored by the Cuyahoga Falls Amateur Radio Club today. I didn’t find anything I was looking for because I wasn’t looking for anything, but did see a lot of interesting stuff. The one that caught my eye was a complete Heathkit amateur radio station with transceiver, speaker, ‘scope, and tuner. It was nice and clean and functional. And boy did it bring back memories! I was a very avid Heathkit builder back in the 60’s to 80’s era….my first ham radio, my first VTVM, my first oscilloscope, and my first computer, among a whole bunch more. I loved putting those kits together, testing them and then using. But Heathkit eventually went out of business, several times if I remember correctly. And I sold off each of those kits over the years for bigger,...

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Tracking down bad caps

Posted on Jul 29, 2013 | Comments Off on Tracking down bad caps

I just added a new tool to the workbench and I’m loving it: Atlas ESR70. I work on a lot of power supplies, computers, transceivers,  LCDs, printers (you get the drift, right?) and find that capacitors don’t always have to “leak” to be bad. Here’s a pic of some bad capacitors. Easy enough to spot the bad ones, right? After replacing the three bulging caps though, the system did not come up. The ESR meter allows me to test for the equivalent series resistance in circuit, which is often impossible with a capacitance meter or DMM. And this particular model of ESR meter discharges a capacitor before measuring. . . so no blown meter innards. An ideal capacitor has a zero equivalent series resistance, and failure of a capacitor can be seen as an increase in its ESR. Well, the...

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