STEP 01
Photograph before touching
Take clear photos of the cabinet, chassis top and underside, dial-string path, plugs, tube positions and every area you may disturb.
Start here
A careful first restoration
The most valuable work often happens before the soldering iron is warm. This sequence helps you document the set, find the right information and avoid preventable mistakes.
STEP 02
Identify the exact version
Record the manufacturer, model, chassis number, serial number, country and mains voltage. Do not assume a similar-looking model is electrically identical.
STEP 03
Find service information
Locate the schematic, alignment instructions, tube layout and parts list. Read the notes and production-change pages.
STEP 04
Inspect before power
Check the cord, fuse, transformer, burnt parts, loose hardware and signs of earlier repairs. Do not simply plug in an unknown radio.
STEP 05
Build the parts list
Compare the chassis against the schematic. Record capacitance, resistance, voltage or wattage, polarity, quantity and lead spacing.
STEP 06
Repair in small stages
Change a small group of parts, inspect the work, then recheck connections. Preserve lead dress around RF and audio circuits.
STEP 07
Power up deliberately
Use appropriate current limiting, isolation and test equipment. Watch current draw, B+ voltage, smoke, heat and unusual noises.
High-voltage warning
Tube equipment can contain several hundred volts. Filter capacitors can remain charged after the set is unplugged, and an autotransformer radio may place the chassis at mains potential. If you are not trained to work safely around these hazards, ask an experienced technician for help.