Tools & Testing Equipment

For Repairing Tube-Type Radios

By Doug Criner

Much of the equipment shown on this page is not at all essential for servicing tube-type radios.  Some of my equipment, such as an oscilloscope and frequency counter, is a legacy from my past electronic interests—totally unnecessary equipment for antique radio work, but sometimes handy.

Weller 8200-N 100/140-W soldering gun.  Any rosin-core, 60/40 solder is fine.

An analog volt-ohmmeter (l) or a digital multimeter (r) is essential.  My Fluke multimeter also measures capacitance.

The long-out-of-print RCA Radiotron Handbook is available on CD and a complete set of John F. Rider radio schematics are available on DVD.  (Most of the Rider schematics are available for free at http://www.nostalgaair.org )

Two very helpful reference books.  Either provides tube basing and pin assignments.

The usual hand tools:  needle-nose pliers, nippers, wire stripper, and nut drivers.

An assortment of rather expensive 600-V "Orange Drop" polypropylene, film-type capacitors.  The cheaper 715P series of Orange Drops is perfectly adequate as are the no-name, yellow, metalized film caps.  Really, any modern caps of the appropriate value and voltage rating should be fine.

An assortment of electrolytic capacitors.  Multi-section caps, such as the red cap shown above, can be replaced with cheaper, individual 450-V caps.  The blue caps are cheapo Asian units; higher quality Sprague "Atoms" are more expensive and bulkier.

Resistors seldom need to be replaced, but it's handy to have an assortment available.

Supplies for cleaning contacts, rheostats, and chassis.

A variac is useful for testing old radios at reduced voltage in case there is a short circuit.  This no-name Chinese model from All Electronics Corp. is rated at 500 VA/5 A, which is plenty.

An isolation eliminates some but not all risk of shock.  This one is rated 250VA and weighs about 12 lb.

Eico 324 signal generator can inject either RF or audio signals.  I seldom need to use this device.

Eico 147A signal tracer--a companion to the signal generator.

An oscilloscope is handy, but not essential.  My 20-MHz model is overkill for radio work.

This old H-P Model 5245L frequency counter is occasionally helpful in checking I.F. oscillators.  This model is a real "boat anchor," with a nixie-tube display.

This inexpensive BC/SW/LW/AM/FM digital radio makes a fine frequency counter and wireless signal tracer.  It tunes low enough, below the BC band, to pick up I.F. frequencies (e.g. 455kHz).

Heathkit TC-2 tube tester.  This is an emissions tester, which measures plate current; more sophisticated, trans-conductance testers, such as many Hickok models, also measure the tube's amplification.  Any tube tester is a luxury--a very good tube checker is the radio in which the tube is to be used.

Spaghetti (l) for insulating leads and a spool of dial cord.  Both are essential to keep on hand.

Supplies for rejuvenating plastic and wood cabinets.

Stain and filler for concealing minor imperfections in wood cabinets.  Available at home improvement centers.

© Doug Criner, 2004