Philco model 49-505

Go down

Philco model 49-505

Post by Ed in W. PA on Mon Sep 15, 2014 11:48 pm

I am re-caping a Philco model 49-505 and have a question concerning one of the capacitors. C 302 is connected between the B- line and the chassis. It is a IF bypass capacitor and is marked .2 mfd @ 400v and is marked "special construction". The schematic shows it as a coil and capacitor in series. The text of the Riders schematic describes this cap as being inductively wound to form a series tuned circuit resonant at the intermediate frequency offering less impedance at this frequency thus permitting higher IF gain. Does anyone have any experience with this? The cap I have is leaky and must be replaced, and I need to come up with a replacement. Any input would be greately apreciated. Thanks, Ed.

Ed in W. PA
Member
Member

Number of posts : 117
Registration date : 2014-02-17

Back to top Go down

Re: Philco model 49-505

Post by Dr. Radio on Tue Sep 16, 2014 4:57 pm

Ed,

Simply replace it with a regular cap. Read that modern cap. A safety "y style" would be ideal to prevent the typical AC/DC chassis shock hazard. You won't find a "y safety cap" in that large of a value....but for testing, a regular cap will do.

Back in the day ship/shore stations transmitted around the same IF frequency and this cap was to "bleed" off any unwanted interference from such xmitters as not to get into the radios IF stages. Today it's a non issue.

Go ahead and try it. Smile
avatar
Dr. Radio
Member
Member

Number of posts : 937
Age : 37
Registration date : 2012-09-17

Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum