Replacing Capacitors
| Capacitor Types | Replacing Electrolytic Capacitors | Replacing Non-Electrolytic Capacitors |
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Capacitor Types
Paper/Wax Paper Capacitors:
These non-polarized capacitors are very unreliable. Replace these with Sprague Orange Drops or tubular film capacitors.
Ceramic Capacitors:
These non-polarized capacitors are round & flat and are extremely reliable. DON'T replace these without a good reason.
Mica Capacitors:
These non-polarized capacitors are squarish and flat, thicker than ceramic, usually with color-coded dots. These are reliable, so DON'T replace these without a good reason.
Tubular/Molded Paper:
These non-polarized capacitors are just paper capacitors in plastic shells, meaning they're very unreliable. Replace these with Sprague Orange Drops or tubular film capacitors.
Electrolytic Capacitors:
These polarized capacitors are typically the largest in the radio or TV set. These capacitors typically fail from drying out, however capacitors made between 1999 & 2010 fail due to a mis-copied formula. Be sure to test electrolytics with higher/more unusual values before replacing them, since some (such as Sprague) are more reliable than others.
Replacing Electrolytic Capacitors
The mechanics of disconnecting the old capacitor and soldering in the new one are the same for electrolytic capacitors, however you must observe the proper polarity of the capacitor and it's recommended that you use capacitors that are +/- 20% of the original value.
Electrolytics are special in a couple of ways, however. First, their large capacitance value means that they can store an electrical charge—enough to deliver a painful shock—even when the radio is turned off and unplugged. Before touching the leads of an electrolytic capacitor, discharge the cap by shorting its leads together with an insulated clip lead.
Most electrolytics contain metal foil and a paste, which dries out over time and causes failure. In 1930s or earlier radios, you may find a "wet" electrolytic, which contained a solution of boric acid rather than paste.
Replacing Non-Electrolytic Capacitors
Tube Substitutions
