Hi there,
I picked up a Philco 46-427 at a local swap meet. All it produces right now is some pretty nasty static, so I have been going through the motions of troubleshooting last night, starting with the power supply.
Voltages after rectifier and double-cap were wayy too low, so I clipped the double 20uF and wired in new replacement electrolytics, which got the voltages to where the circuit diagram says they need to be (~112V/~85V). But there still isn't any improvement. Since the filaments all light up, I want to first replace all capacitors. But...
I guess I am too young to understand some of the values the parts list contains... ;-)
Example: C201 is listed as 250mmf. What would that be in uF/nF/pF?
Also, what types of capacitors should I chose for those replacements?
Any advice for someone who mostly grew up with silicone-based circuitry?
Thanks much!!
Stefan

mmf is the same as pf today... You will want to restore all the electro. caps and all the wax paper caps...I would sugest leaving all others...Also replace any resistors that are way out of spec. Over time some of the carbon resistors go out of tollerance...Then slowly bring set up to power on a variac...
:Hi there,
:I picked up a Philco 46-427 at a local swap meet. All it produces right now is some pretty nasty static, so I have been going through the motions of troubleshooting last night, starting with the power supply.
:Voltages after rectifier and double-cap were wayy too low, so I clipped the double 20uF and wired in new replacement electrolytics, which got the voltages to where the circuit diagram says they need to be (~112V/~85V). But there still isn't any improvement. Since the filaments all light up, I want to first replace all capacitors. But...
:I guess I am too young to understand some of the values the parts list contains... ;-)
:Example: C201 is listed as 250mmf. What would that be in uF/nF/pF?
:Also, what types of capacitors should I chose for those replacements?
:Any advice for someone who mostly grew up with silicone-based circuitry?
:Thanks much!!
:Stefan
:

Thanks George, I had almost convinced myself of the pF answer, given where in the circuit the mmF caps were.
What would be the best type of cap to use when replacing the wax paper caps? Ceramic?
Also, is it a good idea to replace the ones that are part of the I-F transformers on both sides of the 7B7 tubes?
Appreciate the help!
Stefan

:mmf is the same as pf today... You will want to restore all the electro. caps and all the wax paper caps...I would sugest leaving all others...Also replace any resistors that are way out of spec. Over time some of the carbon resistors go out of tollerance...Then slowly bring set up to power on a variac...
::Hi there,
::I picked up a Philco 46-427 at a local swap meet. All it produces right now is some pretty nasty static, so I have been going through the motions of troubleshooting last night, starting with the power supply.
::Voltages after rectifier and double-cap were wayy too low, so I clipped the double 20uF and wired in new replacement electrolytics, which got the voltages to where the circuit diagram says they need to be (~112V/~85V). But there still isn't any improvement. Since the filaments all light up, I want to first replace all capacitors. But...
::I guess I am too young to understand some of the values the parts list contains... ;-)
::Example: C201 is listed as 250mmf. What would that be in uF/nF/pF?
::Also, what types of capacitors should I chose for those replacements?
::Any advice for someone who mostly grew up with silicone-based circuitry?
::Thanks much!!
::Stefan
::
:
:

Never mind, just found this: http://www.justradios.com/captips.html
:-)

:Thanks George, I had almost convinced myself of the pF answer, given where in the circuit the mmF caps were.
:What would be the best type of cap to use when replacing the wax paper caps? Ceramic?
:Also, is it a good idea to replace the ones that are part of the I-F transformers on both sides of the 7B7 tubes?
:Appreciate the help!
:Stefan
:
::mmf is the same as pf today... You will want to restore all the electro. caps and all the wax paper caps...I would sugest leaving all others...Also replace any resistors that are way out of spec. Over time some of the carbon resistors go out of tollerance...Then slowly bring set up to power on a variac...
:::Hi there,
:::I picked up a Philco 46-427 at a local swap meet. All it produces right now is some pretty nasty static, so I have been going through the motions of troubleshooting last night, starting with the power supply.
:::Voltages after rectifier and double-cap were wayy too low, so I clipped the double 20uF and wired in new replacement electrolytics, which got the voltages to where the circuit diagram says they need to be (~112V/~85V). But there still isn't any improvement. Since the filaments all light up, I want to first replace all capacitors. But...
:::I guess I am too young to understand some of the values the parts list contains... ;-)
:::Example: C201 is listed as 250mmf. What would that be in uF/nF/pF?
:::Also, what types of capacitors should I chose for those replacements?
:::Any advice for someone who mostly grew up with silicone-based circuitry?
:::Thanks much!!
:::Stefan
:::
::
::
:
:

or try radiodaze.com for all the wax paper caps you can use the cheaper metallized polyester film ..I have never had any problems with them ..plus they are not polarized so you can not put them in the wrong way..