[klondike98]

Hey Ron...here's my thinking so far.  Assuming I need to carry 20ma as Terry suggested (although for a different radio...an Emerson 25A) I figured I needed something like a Hammond 155J..  The hole mounts are not quite right but that model is the closest physical fit and I think I can make it work.  The "J" is good for 30ma at 15H,  the next one down is 155C which is good for 8ma with 60H.  I had planned on buying the 155J but then found a thread on ARF that discusses using the 155C and it seems to work out OK.  The ARF thread fellow did what I had planned with the mounting holes and 60H is a lot more than 15H....let's see what Terry has to say...

Calling Radioroslyn...calling Radioroslyn....  

[Radioroslyn]

Oh no you found me [Image: http://philcoradio.com/phorum/images/smi...n_evil.gif].

I'm not quite sure why Philco decided to feed the screen voltage to the mixer and if amp thru that choke, It would seem much simpler just feed it from b+ that is over by the output stage. See the schematic for the model 60. It's pretty much the same - the choke.

If I was going to replace the choke I would try a resistor to mimic the choke. Value would depend the voltage drop (abt 175v). The screen grid current between is abt 6ma. If you do the math it ends up being abt 138K taking into account the 32K series resistor that is connected to the screen itself. In the real world a choke that measures any where near that resistance would be off the charts in terms of inductance.

Once a proper value resistor is connected you may have an issue w/bypassing the rf energy that's on the screen grid so adding a small value cap (.001-.005 630v) from the screen the chassis should take care of it.

[Ron Ramirez]

> It would seem much simpler just feed it from b+ that is over by the output stage.

I tried that once some years ago in a 66, and the set hummed until I redid it correctly with a choke, following the factory schematic. As I recall the original choke was bad but I found one in a junk Philco, either another 66 or possibly a 45, and it took care of the hum.

[klondike98]

Ron, I did order the 155C Hammond choke from RadioDaze and followed the advice of the fellow on ARF to make it fit into the chassis.  Pretty simple really, just opened up one of the two mounting holes since the mounting screw needs to go right where outside of the metal is located.  Then I added a small washer to hold it all down.  The new choke is smaller than the original.  Here's a pic of it mounted with the washer arrangement, but not yet wired in.

[Image: https://www.dropbox.com/s/al4qfkz0lzkvcg....jpg?raw=1]

and a final shot of the underside of the chassis...pretty much looking all original except for that new choke.  I thought about trying to fit it into the old housing but decided to leave well enough alone.

[Image: https://www.dropbox.com/s/fyimh4wvarjmzc....jpg?raw=1]

Its now aligned and playing.  Its a pretty good receiver, picking up more broadcast stations than I usually hear on the short 10' wire antenna I have in the shop.  Am also picking some SW on it.  It also picks up every bit of hash and static around.  I had to turn off my shop lights, which did cut the static a lot.  Most of the sets I've worked on were not as affected by those lights.  In doing this alignment I realized the new digital multimeter that I got only has a frequency counter that goes up to 500kHz.  I really need to calibrate my signal generator but have been using a multimeter counter (that died not too long ago) so never got around to it. That will be another project!

[Image: https://www.dropbox.com/s/wbsalgks8nhs4s....jpg?raw=1]

The cabinet will get stripped this winter, but that's another thread...