I have a Zenith trans-oceanic I am repairing, somone has put in the wrong electroyltic capacitor, I know the correct values from the schmatic but I do not know the voltage rating( they put in all 450volts)I would think that 160volt units would be more than fine. it is a Modle T600L chassic # 6T40. I was told it is ok to go a little over on the voltage rating but not way over,why is the reasoning for this?

You can use 450 volt electrolytics. They will work just fine. Where you don't want to go too far over is with capacitance. With voltage, use the same or higher value. Some say that an electrolytic with a very high voltage rating won't stay properly formed when run on a lower voltage. However, what forms an electrolytic initially is voltage. Whatever voltage is used to form the electrolytic is usually the voltage that the electrolytic will safely operate at. If you use the electrolytic at a voltage lower than what it is rated for, the di-electric formation may deteriorate, but it'll only deteriorate down to the voltage you are using it at. As long as the electrolytic doesn't go bad for other reasons, the voltage you operate it at will keep it formed safely for that voltage.

I, and many others, have never run into trouble when using an electrolytic that's rated much higher than the voltages encountered in the circuit it is used in. I would not be surprised if the electrolytic could later be used in a circuit in which the voltage is near its maximum rated value.

T.

:I have a Zenith trans-oceanic I am repairing, somone has put in the wrong electroyltic capacitor, I know the correct values from the schmatic but I do not know the voltage rating( they put in all 450volts)I would think that 160volt units would be more than fine. it is a Modle T600L chassic # 6T40. I was told it is ok to go a little over on the voltage rating but not way over,why is the reasoning for this?

Ralph: original specs were for 150v filter caps, so as Thomas has pointed out, 160's are just fine. TO's aren't really that finickey about capacitance values on filter caps either. Instead of 60, 40, and 20 mfd, I used three 47's with radial leads on a terminal strip on my L600 and it works perfectly. You can see the same method on Joe Urbanovitch's website: http://www.radiosphonos.com/store/prodimg/tochassis/
Steve