Hello,
I am going to change the E caps in this radio. One of the caps is 100 Mfd and is connected to the cathode of the 35W4 through a 100 ohm 2 watt resistor. The lagest cap i have is 80 Mfd.
Will the be ok to use or should i buy a 100 Mfd?
Thanks
Mitch

You should be OK, provided you observe the polarity, and the capacitor is at or above the rated voltage. If it's a NOS part, bring it up slowly with a variac to let it form properly. Incidently, 100 mf or even 80 mf is pretty large, are you sure of the original value?

:Hello,
:I am going to change the E caps in this radio. One of the caps is 100 Mfd and is connected to the cathode of the 35W4 through a 100 ohm 2 watt resistor. The lagest cap i have is 80 Mfd.
:Will the be ok to use or should i buy a 100 Mfd?
:Thanks
:Mitch
:

:You should be OK, provided you observe the polarity, and the capacitor is at or above the rated voltage. If it's a NOS part, bring it up slowly with a variac to let it form properly. Incidently, 100 mf or even 80 mf is pretty large, are you sure of the original value?
:
::Hello,
::I am going to change the E caps in this radio. One of the caps is 100 Mfd and is connected to the cathode of the 35W4 through a 100 ohm 2 watt resistor. The lagest cap i have is 80 Mfd.
::Will the be ok to use or should i buy a 100 Mfd?
::Thanks
::Mitch
::
:
:
The schematic is here at NA, parts list and schematic both call for 100 Mfd at 150 VDC. My 80 Mfd is rated at 160 VDC.
Thanks for the response.
Mitch

If there is a 100 ohm resistor between the 100 MFD cap and the rectifier, it should be fine in any case. The 100 ohm resistor will limit surge current and prevent damage to the rectifier. At the same time it will further smooth the DC. Ordinarily a 50 MFD capacitor is used here, but usually it is connected directly to the rectifier. A larger unit here would cause flash-over during a warm turn-on.

Also, if the radio exhibits no hum and the original units measure proper value with low leakage, and show no physical signs of deterioration, they do not need replacement.

T.

:If there is a 100 ohm resistor between the 100 MFD cap and the rectifier, it should be fine in any case. The 100 ohm resistor will limit surge current and prevent damage to the rectifier. At the same time it will further smooth the DC. Ordinarily a 50 MFD capacitor is used here, but usually it is connected directly to the rectifier. A larger unit here would cause flash-over during a warm turn-on.
:
:Also, if the radio exhibits no hum and the original units measure proper value with low leakage, and show no physical signs of deterioration, they do not need replacement.
:
:T.
:
T.
The radio does exhibit hum through out the tuning. It is a can cap so i will replace all three caps.
Thank you
Mitch

If the radio does exhibit hum throughout the tuning range, and even with the volume control turned down, then the electrolytic caps are likely losing capacity (drying up), and are good candidates for replacement.

T.

:If the radio does exhibit hum throughout the tuning range, and even with the volume control turned down, then the electrolytic caps are likely losing capacity (drying up), and are good candidates for replacement.
:
:T.
:
T.
The hum is evident even with a station tuned in. When the volume is turned down the HUM is evident to the ear as a noise Hummmmmmmm.
Look to change cap's because i don't know which one it is and i don't have a high volt cap tester. Cheaper to just change all three as they are in a single can.
Thanks for the reply and info,
Mitch

This is true. If they are all in one can and one is failing, they will and/or are failing.

T.