Switches

Anyone who's poked around in old electronic devices for any length of time knows that switches & dials are some of the first components to go bad. They don't go all-the-way bad instantly, like a blown resistor. Over time they get gritty, temperamental, intermittent, and just refuse to work right. They slowly fade away, and then one day... nothing. While most electronic components (resistors, capacitors, transistors, diodes, etc.) just sit there and pass electrons, switches and dials are the mechanical man-machine interfaces that undergo the most 'fiddling'. It only makes sense that, with all that poking, twisting and prodding, they tend to be the first things to go wonky. (Touch screens are a fairly recent development that are coming on fast when it comes to component failure rates, but plain old switches and dials have over 100 more years of failure to lay claim to.)

I've done some recent work on older Elecraft and Yaesu rigs with front panel switches that were getting sticky or non-responsive. While a quick spritz of contact cleaner helped with some of the misbehaving parts, others required more intensive surgery. In the case of the Elecraft, it required a complete disassembly of the radio, peeling the 'snap dome' contact pads off of the main board, cleaning 12 years of corrosion off of the board contacts, and installing new snap domes and rubber buttons. Kudos to Elecraft for still making these parts available, at a very reasonable price.

Some may think that once switches or dials go bad on any old electronic device, it's time for that sad trip to the landfill. But not one of my favorite YouTubers, CuriousMarc! Marc's wonderful and entertaining channel follows him and his very talented team of nerds as they bring back to life all sorts of vintage electronic or electro-mechanical gear. Marc's first love is old HP test equipment and early computers, followed closely by anything associated with spaceflight. But Marc also has a place in his heart for vintage DEC and Sun computers, classic IBM 'heavy iron' mainframes, mechanical teletypes, calculators, old TVs, and more. Basically, if it's got either blinking lights or it makes a lot of mechanical chatter (like a teletype), it catches Marc's attention. It also helps that Marc's videos are some of the best produced on YouTube. Everything from presenting the background story and research, to camera angles and lighting, on-screen comments by team members, editing, and final production is first rate. There's a lot of subtle humor woven into the narration, but it's often humor you need to be a geek to appreciate. And it's all very family friendly.

Recently Marc posted a series of videos about bringing a old HP 3438A digital volt meter back to life. There's nothing really remarkable about this meter, other than someone gave it to Marc and he was determined to get it working again. That and the fact that it's HP, and Marc can't let any piece of vintage HP test gear on his bench without opening it up and trying to make it work right. Right off the bat, Marc deduced that the problem was mostly in the switches. These were a common switch design used by HP in the 70s & 80's, and they had a high failure rate due to some unusual wear patterns. New switches are unobtainable, and Marc didn't have a donor piece of test gear, so he had to repair or alter what was in front of him. This led to a very interesting discussion about switches, and some of the ways you can alter what you have to bring a piece of vintage gear back to life. 

Many hams tend to think that, just because a radio or other piece of electronic gear doesn't have hundreds of moving parts, like a car, it just naturally lasts longer. Not so. There are conscious design and engineering decisions made that limit the lifespan of many of the devices we depend on. The best example is smartphones. The manufacturers know that, within 6 - 8 years of a device's release, it will be obsoleted by factors outside the manufacturers control - things like changes to carrier services (Edge to 3G to 4G to 5G), changes to wi-fi or Bluetooth standards, etc. So Apple, Samsung, Google and others design and build their devices using components that they know won't survive much past a decade of use. Planned obsolescence, on many levels. This is one of the reasons I've groused a bit on this blog about the electronics repairability issue. 

And this is why I love CuriousMarc's channel. He proves that, if a piece of equipment was designed well, and used quality components, it can be maintained and remain useful far beyond the manufacturers original design lifespan.

W8BYH out