Old radio restoration methods, Recovery technologies, Tips and Tricks

Workshop Hints
Checking Filter Condensers A handy tool consisting of an electrolytic condenser with a lead and test prod soldered to each terminal will enable filter condensers to be readily checked. To use the tool , simply turn on the set and apply positive and negative leads to the corresponding terminals of the condenser in question. Tho output of the set will... read more >>

The Philips 1561 tube base modification
Alteration of the 1561 Philips vacuum tube to use it as a regular 4 prong american tube, like the type 80 or the 5Z3, or even 5Y3 , 5U4 etc.... read more >>

Replacing The Old Capacitors in Rare Radio

When you begin to restore a set from the 50's or older, it is hotly debated whether or not you should replace all of the paper capacitors or not. Purists and collectors feel that they should only be replaced if absolutely necessary, and if so, the new ones should be hidden inside of the old cap casing for appearances. It... read more >>

Repairing an Old American Radio
Checking and repairing power supply and filaments line The first step to repair an old radio is to check the filament of each tube. If one is open, all the line is out of order. So, first of all, take out each tube and check the filament with your ohmmeter. If one is ruined, change the tube. You also... read more >>

Paper capacitor restoration
It's a well-known fact that electronic parts alter their electric characteristics during prolonged storage. The paper capacitors are not exception. These capacitors are often used in domestic household radios from 1950 - 1960-ies. It is impossible to find such capacitors, not previously used, because old stocks are not. The main criteria by which we can determine that the capacitor... read more >>

Old radio schematic symbols
... read more >>

Old radio restoration approaches
Restoration. How do we proceed? Assessment: When we start restoring we will have to look at the device for defects and write this down. Then assess whether the parts we need are available because to restore an incomplete radio is a waste of time. Make sure all parts are present. Example list: 2x scale light 6.3V 0.2A, a... read more >>

Interstage Audio Transformers Repair
Even for the novice, 1920's battery sets can be easy to get going, once the power supply problem has been solved. Repair of battery sets generally consists of checking the wiring (many times these were tinkered with by a previous owner, probably to see if he could 'soup it up' to get performance like a newer set?), cleaning contacts,... read more >>

Common symptoms and remedies of noises in a old radio
Troubleshooting with noise other than the random type, we must however recognize the latter when it bears a relation to other troubles. One advantage in tracing noise problems or troubles is that most noises have a characteristic sound or sounds, which allow us to classify each type when we hear it. The type of sound gives a clue to its... read more >>

Attaching a Magic Eye to your Radio
With the finest radio receivers now featuring visual "Tuning eyes" you may have wished for such a device on your own receiver. Any receiver employing a diode secondary detector tube can be fitted with a tuning eye in a few minutes . The tuning eye itself is nothing more than a type 6E5 tube readily obtainable at your nearest... read more >>

Antique capacitors types
Paper/Wax These are usually 1/4" to 3/4" wide wax covered cardboard cylinders with leads coming out of wax plugs at each end. Occasionally, they can also be found as rectangular metal "bathtub" cans with values stamped on them, but no polarity markings. Paper caps are the most abundantly used type, found in all areas of the radio circuit for general... read more >>

AM band adjustment
Cascades of high frequency radio contain input circuits, and UHF frequency converter. The main objective when adjusting these cascades are checking LO generation and setting its contours, adjustment the gain stage higher frequency signals and the coupling configuration input circuits, UHF and LO. Do not use a screwdriver for adjusting! A screwdrivers blade affects the tuning, but you need... read more >>

A Lightbulb-Based Short Circuit Indicator and Over-current Protector

Whether it's that new untried set that you just brought home from the auctions, or that chassis that you just re-capped, who hasn't felt some apprehension when reaching for the power switch for the first time. This simple project will help ease that apprehension, and might just prevent the serious damage caused by a short circuit.

Antique radios... read more >>

A brief guide to troubleshooting the old radios
Absence of Signals Burnt out rectifier valve Broken down filter capacitors Open-circuit field winding or filter choke Short in H.T. by-pass capacitors Open circuit cathode resistors H.T. supply line open circuit Open circuit R.F. or I.F Coil Shield can shorting to grid cap Disconnected wiring Faulty valve socket or speaker connection Low B+ Voltage Poor Volume Weak valves Low... read more >>

6AE8 Replacement
The 6AE8 tube was a 9 pin triode-hexode frequency converter used in sets from the early to the late 1950's. It can be a little hard to find a replacement in your valve stock so to avoid having to actually buy a tube you can substitute a much more readily available 6AN7. However the 6AN7 while very similar in characteristics... read more >>

Tube Bias
The main purpose of grid bias is to set the operating point of the valve near the centre of the straight (ie linear) portion of the characteristic curve when the valve is receiving no signal. The grid is set at a negative potential with respect to the valve's cathode.A number of ways of achieving this result will be encountered in... read more >>

Soldering rules for antique radios
Soldering Is Simple...If You Do It Correctly! Note: Below I refer to the soldering to be done on such circuits as might be found in antique radios, using a soldering gun of at least 100 watts. Soldering pencils and soldering irons are for printed circuit board soldering.

Basic Tools:

Soldering Gun - with a minimum 100 watts... read more >>

Radio cabinets veneer restoration
Old radios: How to fix veneer that is lifting (Method was written by Floyd Sense)

Use putty only if the chip is in an inconspicuous place and you'll be using a toner spray over it. You could then hide it pretty well. If it can be easily seen, I'd go with replacement veneer. Be aware that veneer comes in... read more >>

Philips dial lamps
This page contains the data of all scale lighting lamps that are used in the common radios. Original Philips numbering has been preserved. (First column.) Then the voltage and the current follow. An image of the lamp is included in the fourth column. Bulbs with an "N" after the type number have a bayonet fitting (BA9s), those with the letter... read more >>

Padder Feedback
Padder feedback was/is a technique for boosting the action of the oscillator section of the frequency changer valve in Superheterodyne receivers. Some sets had it incorporated in the factory as in the 520M. It can also be added to existing circuits by the restorer to boost the effectiveness of a weak frequency changer valve -as these valves age, the oscillator... read more >>

Old resistors color code
... read more >>

Mica capacitor color codes
... read more >>

Antique Radio Safety: Understanding the Dangers of a Hot Chassis

Many antique radio chassis are "hot", meaning that they can have dangerously high voltages exposed externally. This presents a serious shock hazard, unless you understand what precautions to take.

In the environment of relaxed electrical safety codes of yesteryear, many radios were manufactured with the metal chassis electrically connected to one side of the power cord. This can... read more >>