I have an early 50's Silvertone Power Shiftr battery eliminator. I want to recap it to get the correct voltages but have some questions. It calls for (2) 1500 MFD 3 volt caps, (2) 40 MFD 150 volt caps, and an 1800 ohm 1 watt resistor. The 4 caps appear to be electrolytics due to the + symbol on one end of them. When Im replacing them, do I need to get as close as possible to the rated voltage or do I want to go higher to protect the components? If I substitute a 40 MFD 250 volt electrolytic for the 150 volt one will that be okay? Also substitute a 1500 MFD 50 volt for the 3 volt? Any advise would help.

Have re-built a couple of those Sears Power Shifters.
You can use higher voltage capacitors for the filament supply. Same for the B+ supply. Robbed a computer power supply for all the needed capacitors.

:I have an early 50's Silvertone Power Shiftr battery eliminator. I want to recap it to get the correct voltages but have some questions. It calls for (2) 1500 MFD 3 volt caps, (2) 40 MFD 150 volt caps, and an 1800 ohm 1 watt resistor. The 4 caps appear to be electrolytics due to the + symbol on one end of them. When Im replacing them, do I need to get as close as possible to the rated voltage or do I want to go higher to protect the components? If I substitute a 40 MFD 250 volt electrolytic for the 150 volt one will that be okay? Also substitute a 1500 MFD 50 volt for the 3 volt? Any advise would help.
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Higher voltage is just fine. Generally the price of electrolytic caps is roughly proportional to the product of the capacity times working voltage- high-capacity high voltage caps are therefore relatively expensive, so from a manufacturing recurring-cost standpoint it makes sense for a design engineer to specify the lowest voltage rating that he can get away with in any given application.

High-capacity low-voltage electrolytics are relatively common (and cheap) these days due to their extensive use in solid-state electronics. They are also very compact compared with equivalently-rated devices of 70 years ago.

While higher-voltage devices are OK, try to stick to the same capacitance value as the original part for filter applications. Up to 100% higher is generally OK but above that it's possible to damage the circuit it is used in either through current overload on the driving device (usually a rectifier) or (less likely) by creating an overvoltage condition for the downstream components.

::I have an early 50's Silvertone Power Shiftr battery eliminator. I want to recap it to get the correct voltages but have some questions. It calls for (2) 1500 MFD 3 volt caps, (2) 40 MFD 150 volt caps, and an 1800 ohm 1 watt resistor. The 4 caps appear to be electrolytics due to the + symbol on one end of them. When Im replacing them, do I need to get as close as possible to the rated voltage or do I want to go higher to protect the components? If I substitute a 40 MFD 250 volt electrolytic for the 150 volt one will that be okay? Also substitute a 1500 MFD 50 volt for the 3 volt? Any advise would help.
::
:= = = = = = =
:
:Higher voltage is just fine. Generally the price of electrolytic caps is roughly proportional to the product of the capacity times working voltage- high-capacity high voltage caps are therefore relatively expensive, so from a manufacturing recurring-cost standpoint it makes sense for a design engineer to specify the lowest voltage rating that he can get away with in any given application.
:
:High-capacity low-voltage electrolytics are relatively common (and cheap) these days due to their extensive use in solid-state electronics. They are also very compact compared with equivalently-rated devices of 70 years ago.
:
:While higher-voltage devices are OK, try to stick to the same capacitance value as the original part for filter applications. Up to 100% higher is generally OK but above that it's possible to damage the circuit it is used in either through current overload on the driving device (usually a rectifier) or (less likely) by creating an overvoltage condition for the downstream components.
:
Thanks for the info guys, thats what I was wanting to know!

:::I have an early 50's Silvertone Power Shiftr battery eliminator. I want to recap it to get the correct voltages but have some questions. It calls for (2) 1500 MFD 3 volt caps, (2) 40 MFD 150 volt caps, and an 1800 ohm 1 watt resistor. The 4 caps appear to be electrolytics due to the + symbol on one end of them. When Im replacing them, do I need to get as close as possible to the rated voltage or do I want to go higher to protect the components? If I substitute a 40 MFD 250 volt electrolytic for the 150 volt one will that be okay? Also substitute a 1500 MFD 50 volt for the 3 volt? Any advise would help.
:::
::= = = = = = =
::
::Higher voltage is just fine. Generally the price of electrolytic caps is roughly proportional to the product of the capacity times working voltage- high-capacity high voltage caps are therefore relatively expensive, so from a manufacturing recurring-cost standpoint it makes sense for a design engineer to specify the lowest voltage rating that he can get away with in any given application.
::
::High-capacity low-voltage electrolytics are relatively common (and cheap) these days due to their extensive use in solid-state electronics. They are also very compact compared with equivalently-rated devices of 70 years ago.
::
::While higher-voltage devices are OK, try to stick to the same capacitance value as the original part for filter applications. Up to 100% higher is generally OK but above that it's possible to damage the circuit it is used in either through current overload on the driving device (usually a rectifier) or (less likely) by creating an overvoltage condition for the downstream components.
::
:Thanks for the info guys, thats what I was wanting to know!
With that being said, do you think that having old caps and an open resistor in the the eliminator could cause a low voltage(only 23 volts with the radio plugged in with no tubes installed on the the B+) and only 1.3 volts on the filament supply with all the tubes plugged in? It will light up one tube very well but as I plug in the other 3 tubes one by one they slowly get dimmer and with all 4 plugged in none of them will light up. With all tubes plugged in I only have 19 volts on the B+. Without anything plugged into the eliminator it has 3.56 volts on the A+,A- and 118 volts on the B+,B-. Any thoughts?

...With that being said, do you think that having old caps and an open resistor in the the eliminator could cause a low voltage(only 23 volts with the radio plugged in with no tubes installed on the the B+) and only 1.3 volts on the filament supply with all the tubes plugged in? It will light up one tube very well but as I plug in the other 3 tubes one by one they slowly get dimmer and with all 4 plugged in none of them will light up. With all tubes plugged in I only have 19 volts on the B+. Without anything plugged into the eliminator it has 3.56 volts on the A+,A- and 118 volts on the B+,B-. Any thoughts?

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Why not measure the current that your battery eliminator is putting out when connected to the radio? That way you can tell if the problem is insufficient drive capability (bad rectifier in the shiftr) or excessive load (short in the radio that you are trying to power up).

This particular "shiftr" has two independent DC supplies inside it- one to serve the A battery circuit and one for the B battery. The A battery circuit can source quite a bit of current (since it has to power the tube heaters) so if it isn't putting out a couple of amps, you have a problem with the shiftr, not the radio. On the other hand, the B side can only put out a few hundred milliamps, so it wouldn't take much of a load (say, a shorted capacitor) in the radio to pull it down.

A simultaneous problem with both supplies makes me wonder if you don't have a wrong tube type installed in one of the sockets.

:...With that being said, do you think that having old caps and an open resistor in the the eliminator could cause a low voltage(only 23 volts with the radio plugged in with no tubes installed on the the B+) and only 1.3 volts on the filament supply with all the tubes plugged in? It will light up one tube very well but as I plug in the other 3 tubes one by one they slowly get dimmer and with all 4 plugged in none of them will light up. With all tubes plugged in I only have 19 volts on the B+. Without anything plugged into the eliminator it has 3.56 volts on the A+,A- and 118 volts on the B+,B-. Any thoughts?
:
:= = = = = =
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:Why not measure the current that your battery eliminator is putting out when connected to the radio? That way you can tell if the problem is insufficient drive capability (bad rectifier in the shiftr) or excessive load (short in the radio that you are trying to power up).
:
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:This particular "shiftr" has two independent DC supplies inside it- one to serve the A battery circuit and one for the B battery. The A battery circuit can source quite a bit of current (since it has to power the tube heaters) so if it isn't putting out a couple of amps, you have a problem with the shiftr, not the radio. On the other hand, the B side can only put out a few hundred milliamps, so it wouldn't take much of a load (say, a shorted capacitor) in the radio to pull it down.
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:A simultaneous problem with both supplies makes me wonder if you don't have a wrong tube type installed in one of the sockets.

To Warren:
I have been meaning to write about old computer power supplies....my computer guru gives them to me free, and they are FULL of goodies, caps, heat sinks, coils, transistors, high Voltage AC caps, you name it. I am going to experiment with transformerless power supplies soon as I get my lawn under control now that spring has come to Georgia.
Lewis
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