Silvertone 4505

3/21/2012 6:21:52 AMfrank goddard

A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.

What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering

thanks

Frank

3/21/2012 11:23:52 AMNorm Leal

Frank

R7 is identified as 100 ohms:

http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf

This radio has a small power transformer and doesn't require cap/diode dropper.

Norm

:
:
:A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
:
:What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
:
:thanks
:
:
:Frank
:

3/21/2012 4:21:44 PMfrank goddard

Many thanks Norm.

The Resistor R7 is a wire wound. (Now just a black burnt blob)I thought it as a 100 watt resistor hence my reluctance to replace with a similar type. Now explained as a 100ohm what wattage would you reccommend
:Frank
:
: R7 is identified as 100 ohms:
:
:http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf
:
: This radio has a small power transformer and doesn't require cap/diode dropper.
:
:Norm
:
::
::
::A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
::
::What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
::
::thanks
::
::
::Frank
::
:
:

3/21/2012 5:11:01 PMClifton

Mr. Goddard,

On some of the schematics the Omega symbol for Ohm does look like a 'w' and could be confusing.

Clifton

:
:
:
:
:
:Many thanks Norm.
:
:The Resistor R7 is a wire wound. (Now just a black burnt blob)I thought it as a 100 watt resistor hence my reluctance to replace with a similar type. Now explained as a 100ohm what wattage would you reccommend
::Frank
::
:: R7 is identified as 100 ohms:
::
::http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf
::
:: This radio has a small power transformer and doesn't require cap/diode dropper.
::
::Norm
::
:::
:::
:::A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
:::
:::What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
:::
:::thanks
:::
:::
:::Frank
:::
::
::
:
:

3/21/2012 5:15:09 PMNorm Leal

That 100 ohm is in series with a 1V rectifier plate. It can't dissipate much power. Is it a large resistor now? You could use a 2 watt carbon resistor.

Norm

:Mr. Goddard,
:
:On some of the schematics the Omega symbol for Ohm does look like a 'w' and could be confusing.
:
:Clifton
:
:
::
::
::
::
::
::Many thanks Norm.
::
::The Resistor R7 is a wire wound. (Now just a black burnt blob)I thought it as a 100 watt resistor hence my reluctance to replace with a similar type. Now explained as a 100ohm what wattage would you reccommend
:::Frank
:::
::: R7 is identified as 100 ohms:
:::
:::http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf
:::
::: This radio has a small power transformer and doesn't require cap/diode dropper.
:::
:::Norm
:::
::::
::::
::::A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
::::
::::What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
::::
::::thanks
::::
::::
::::Frank
::::
:::
:::
::
::
:
:

3/22/2012 9:42:14 AMfrank goddard

Many thanks.

I will replace with a suitable resistor.By way of interest the original was some 2 inches long coiled wire within a cotton sleeve.
I will keep in mind for the future Clifton the use of the Omega symbol too.

Many thanks to you both

Frank
:
: That 100 ohm is in series with a 1V rectifier plate. It can't dissipate much power. Is it a large resistor now? You could use a 2 watt carbon resistor.
:
:Norm
:
::Mr. Goddard,
::
::On some of the schematics the Omega symbol for Ohm does look like a 'w' and could be confusing.
::
::Clifton
::
::
:::
:::
:::
:::
:::
:::Many thanks Norm.
:::
:::The Resistor R7 is a wire wound. (Now just a black burnt blob)I thought it as a 100 watt resistor hence my reluctance to replace with a similar type. Now explained as a 100ohm what wattage would you reccommend
::::Frank
::::
:::: R7 is identified as 100 ohms:
::::
::::http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf
::::
:::: This radio has a small power transformer and doesn't require cap/diode dropper.
::::
::::Norm
::::
:::::
:::::
:::::A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
:::::
:::::What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
:::::
:::::thanks
:::::
:::::
:::::Frank
:::::
::::
::::
:::
:::
::
::
:
:

3/22/2012 10:03:30 AMLewis L.

:
:
:
:Many thanks.
:
:I will replace with a suitable resistor.By way of interest the original was some 2 inches long coiled wire within a cotton sleeve.
:I will keep in mind for the future Clifton the use of the Omega symbol too.

The "w" looking is the lower case for "Omega" they capitalized it when they started putting capitals for Volt, Ampere, Watt, Henry, Faraday, etc, so they both mean "Omega".
Lewis
Knower if a jillion useless facts.

:
:Many thanks to you both
:
:
:Frank
::
:: That 100 ohm is in series with a 1V rectifier plate. It can't dissipate much power. Is it a large resistor now? You could use a 2 watt carbon resistor.
::
::Norm
::
:::Mr. Goddard,
:::
:::On some of the schematics the Omega symbol for Ohm does look like a 'w' and could be confusing.
:::
:::Clifton
:::
:::
::::
::::
::::
::::
::::
::::Many thanks Norm.
::::
::::The Resistor R7 is a wire wound. (Now just a black burnt blob)I thought it as a 100 watt resistor hence my reluctance to replace with a similar type. Now explained as a 100ohm what wattage would you reccommend
:::::Frank
:::::
::::: R7 is identified as 100 ohms:
:::::
:::::http://www.nostalgiaair.org/PagesByModel/078/M0017078.pdf
:::::
::::: This radio has a small power transformer and doesn't require cap/diode dropper.
:::::
:::::Norm
:::::
::::::
::::::
::::::A friend has given me Sears Roebuck to look at. First thing noted is the open circuit Rectifier Plate resistor. R7 on schematic.
::::::
::::::What would the resistor value have been and replacing this with a modern type would take up a bit of space do you think that a capacitor/diode type dropper is worth considering
::::::
::::::thanks
::::::
::::::
::::::Frank
::::::
:::::
:::::
::::
::::
:::
:::
::
::
:
: