Test Equipment

Start Slowly

It doesn’t take much to get started. Over time as your interest grows so too can the bench clutter. Start with the basics.

Signal Tracer

Simple, but it works.

Minimally you will need a signal tracing instrument such as the Micronata unit shown in Figure 145. They typically sell for between $15.00 and $50.00 on eBay. Be sure you get one that is tested and works.

This is simply a battery-operated transistorized amplifier with a speaker, volume control and test probes. There are three jacks marks COM, AF and RF. Connect the COM to the ground (Common) circuitry in the set being examined. The AF input lets you track down audio signals or the lack thereof. The RF jack sends probe signals through a diode on their way to the amplifier, enabling you to detect radio signals in parts of the set prior to where they become audio.

If the probes are missing you can easily buy or build replacements. These are getting old enough so that you might consider replacing the electrolytic capacitors within. It’s easy to do.

I own one of those, but normally use a device like the one here. It’s a little fancier than the Micronata:

A Tenma 72-540 tracer/injector combo.

Signal Injector/Tracer

The Tenma 72-540 is a combination signal injector and tracer, and it has a meter so that you can see the effects of your work.

They pop up on eBay from time-to-time for under $100.00. These often come without test leads, which you will then need to either buy or build. As you will see momentarily I changed the connectors on mine to accommodate better leads.

Multimeter

Get a decent Multimeter.

You will also want to own a good multi-meter capable of measuring at least AC and DC Volts, and Resistance (Ohms). There are plenty of other features found in multimeters these days, some of them helpful, others not so much.

This is not a good place to skimp. There are plenty of meters selling for under $10.00. I would avoid them all. If you have the budget for a name brand such as Fluke it will probably be money well-spent.

But if you prefer not to spend $100.00 or more, consider the TH036 sold by Amazon. It has an impressive list of features, and routinely receives glowing reviews from users.

A Known Good Radio

As odd as it sounds, a working radio is a handy thing to have on the bench. Do you remember reading about oscillators Back in early chapters? Oscillators do fail occasionally, and you can use an expensive, bulky frequency counter or oscilloscope to track down the oscillator signal or its absence. A little pocket radio can do pretty much the same thing. You can how here.

What? That’s All?

Yup. This should get you rolling

  • Some hand tools
  • A can of contact cleaner
  • A soldering iron
  • An Injector/Tracer
  • A Multimeter
  • And perhaps a working radio

If, however, you want to grow your pile of stuff, there are plenty of ways to do that. Some of these things you can even make yourself.

Test Cables

A variety of cords with alligator and mini clips will come in handy for sure. It’s nice to have a few of these cables with full-size alligator clips on one end and mini-grabbers on the other. Buy or make these. (The store-bought imported ones are often flimsy.)

It's also handy to have piercing probes. These sharp-pointed devices let you get to the wire beneath insulation so that you can take measurements when it would be otherwise difficult or impossible to reach either end of the wire.

Speaker Substitution Box

Speaker substitution It is also useful to have a cable with an earphone plug on one end and alligator clips on the other, or better yet, a small speaker in an enclosure with such a cable attached.

Handy DIY speaker substitution box.

I built it using an old Philco radio case and speaker. It has three ways to contact suspect radios to the test speaker—a standard earphone plug, a mini earphone plug and alligator clips. This combination can help you troubleshoot radio speakers even before you open the case.

Those test plugs on the side of the case let me connect a voltmeter to the output of the radio. This is useful when performing alignments. That toggle switch disconnects the test speaker and substitutes an 8Ω resistor so that no one needs to listen to the radio noises while aligning.

Bridging Capacitor

Bias Resistor Bridge

Advanced Test Equipment

Collectible Vs. Contemporary Test Gear

Battery Tester

Bench Power Supply

Bench Power Supply Quick Change Cables

 

Signal Injector

RF Signal Generator

 

 

Frequency Counter

Analog Vacuum Tube Voltmeter

Transistor Tester

Oscilloscope

Grid Dip Meter

TV/FM/Multiplex Signal Source

Capacitor Tester

Transistor Radio Multi-Purpose Tester

 

Homebrew Gear

Battery Adapters for Power Supplies

Custom Cables and Adapters

Signal Generator Coil

DIY Signal Injector

What Do You Think?

Do you have tips and experiences to share? Questions? Suggested corrections or additions?  Leave a comment below. I’ll review comments and post or incorporate the most useful ones. Your email address is required if you choose to comment, but it will not be shared.

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