3.08.2003
Replacing Capacitors
Replacing Capacitors in Old Radios
...includes links to pages about putting new capacitors into the old can.
Choosing Values of Large Electrolytic Capacitors
For electrolytic capacitors, the same rules apply, except that you can safely use a capacitance value that is considerably higher. In general, you can go as much as 100% higher than the original capacitance value.
For example, when replacing a 10-mfd electrolytic capacitor in the radio's power supply, it is OK to use a 20-mfd or 22-mfd replacement. Likewise, you could replace a 20 with a 33. The higher capacitance may do a slightly better job of removing 60-cycle AC line "hum" from the audio output of the radio. It is not unsafe to go even higher, but you generally won't notice any improvement and the higher-value capacitors (33 mfd, 47 mfd, and so on) are significantly more expensive. Don't waste money on a 100-mfd electrolytic if your radio sounds great with a 20-mfd unit!
Substituting for Unavailable Values
In a pinch, you can combine two capacitors to create one with the desired value. The rule to remember is that when two capacitors are wired in parallel, their values are added.
For example, say that you need a .04-mfd capacitor, but all you have on hand are .02-mfd units. Wire two .02s in parallel, and�voila!�you now have a .04-mfd capacitor. Likewise, wiring two 10-mfd capacitors in parallel creates a single capacitor of 20 mfd. Observe polarity when combining electrolytics (wire both positive ends together and both negative ends together). Both capacitors should have a voltage rating equal or higher than the original.
...includes links to pages about putting new capacitors into the old can.
Choosing Values of Large Electrolytic Capacitors
For electrolytic capacitors, the same rules apply, except that you can safely use a capacitance value that is considerably higher. In general, you can go as much as 100% higher than the original capacitance value.
For example, when replacing a 10-mfd electrolytic capacitor in the radio's power supply, it is OK to use a 20-mfd or 22-mfd replacement. Likewise, you could replace a 20 with a 33. The higher capacitance may do a slightly better job of removing 60-cycle AC line "hum" from the audio output of the radio. It is not unsafe to go even higher, but you generally won't notice any improvement and the higher-value capacitors (33 mfd, 47 mfd, and so on) are significantly more expensive. Don't waste money on a 100-mfd electrolytic if your radio sounds great with a 20-mfd unit!
Substituting for Unavailable Values
In a pinch, you can combine two capacitors to create one with the desired value. The rule to remember is that when two capacitors are wired in parallel, their values are added.
For example, say that you need a .04-mfd capacitor, but all you have on hand are .02-mfd units. Wire two .02s in parallel, and�voila!�you now have a .04-mfd capacitor. Likewise, wiring two 10-mfd capacitors in parallel creates a single capacitor of 20 mfd. Observe polarity when combining electrolytics (wire both positive ends together and both negative ends together). Both capacitors should have a voltage rating equal or higher than the original.
