The PHILCO Phorum

Hi all, been plugging away with the restoration on my great grandmothers radio. Guess I got lucky becasue my rubber coated wires are in fine shape although the colors don't seem to match what the schematic indicates. While I wait for the final installment of more parts and a mail order schematic from Chuck I would like to post a further question. I'm working from a schematic I downloaded, it's not the Rider version but a better quality clearer reproduction using DjView document viewer. Apparently it's a scan of a four page Philco Radio Service Bulletin No. 352. My limited knowledge of reading schematics is probably what is getting me to ask these questions. Consult the picture if that makes it any clearer.

1. Parts list only has a single 0.003 1000v condenser but I have two. Schematic indicates a single condenser, part no. 49 as a 0.003 1000v condenser as part of the (bass) tone control circuit. In my radio there is an additional 0.005 1000V linking the bass and volume pots. Unless, I hear otherwise I plan on just swapping this out and assuming it's serving a purpose.

2.Schematic shows part no. 6 as .05 200V condenser in the lower right hand corner of the chassis to ground. In my radio, there are actually two of these to ground in this corner.

3. Schematic shows part no. 65 as condenser 0.01 - 0.01 mfd, can I assume these are located inside the black plastic block that the power cord connects to? I unscrewed is block and looked behing it but it appears to be solid, nothing to see, so so I've put it back. Should I leave this alone?




Thanks for you helping me along. I'm, actually pretty close to powering her up for othe first time. Wish I had a variac.

Well it looks like the parts you mention are non critical ones #65 is a line filter it is inside that black bakeolite block. What you do is unscrew it, flip it over and you will see the tar that holds the caps in place. You can use a heat gun or not and remove the tar with a small flat screwdriver. Then you will see two shiney things inside. Those are the two .o1mfd caps. Carefully pry them out. If you aren't careful you will break the bakeolite block. If you crack the block wrap some Scotch #33 (black electrical tape) around it and nobody will know. I can keep a secret. Install two .o1mfd@400v or higher voltage rating. Screw it back down and you are all set.
The cap by the tone controls is for tone compensation. Not too much of a big deal. The one or two caps over in the corner are tied into the avc line. There again won't hurt any thing at worst could cause audio to be distorted with a very strong broadcast signal.
Most folks use a variac to reform the electrolytic caps in the power supply. They will slowly increase the ac line voltage in hopes that the lytics in it will not short out but sort of rebuild them selves.This does nothing for the wax/paper caps in the set. In my humble opinion it's a waste of time and if you plan on using the set on a regular basis you are asking for a burned up power transformer and a shorted rectifier tube. If you have replaced the electrolytic and your power transformer is good you don't need to worry about using a variac. Now with that said and you still are concerned you can use a 60 or 100w light bulb in series with one side of the ac line going into the set. This will cut the line voltage down. If it lights to full brilliance you may have a bad (shorted) power transformer. Not very common. Should light to about half brilliance. I'll also mention that most variac are autotransformers in other words they don't have a primary and secondary just a primary. What that means is that they will not provide any isolation. So you would still need to use an isolation transformer when working on an AC/DC set to protect you from the shock hazard.
Good luck w/ it. Sure looks nice!!!
Terry

Thanks Terry, that is good information. I'll dig out my heat gun and replace item 65 (line filter caps), should have done that before I replaced the cord. What would be better for this application: 0.01 uf Ceramic Disk 500V caps I bought from Radio Shack, or 0.01uf 630V Orange Dip caps I bought from Just Radios. I don't have any "safety caps" only now having first read about them. Seems like it's going to be a tight fit.

I heated and dug out the black goo and found the hidden caps in the process. While I was digging the tar material out I managed to sever the cap leads that connects to the power line though the bakelite housing, the leads that went to the ground were remained connected. In an effort to simplify things, I decided to mount the caps on the outside. Each Cap is connected to one side of the power line, and then each cap is grounded to the screw that mounts the bakelite housing. Am I doing this correct?



Also are these caps going to be hot whenever the radio is plugged in?

You should be able to fit them inside no problem. It is important that any of the old lead from the old cap are gone as they could short. You do have the new one connected properly. They won't get hot.
Terry

As long as you went to the trouble of excavating the old components from the bakelite, why not put the capacitors inside ? You need not fill it with tar or wax after this has been done. The radio will not care either way electrically.

Re-stuff those bakelite block condensers just like this:

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Be sure to click on all the pictures for a larger, easy to see size.

Chuck

Thought I would report back and offer thanks for all the help on my project. Couldn't have done it with out this site and others. Powered up the radio for the first time yesterday and it plays wonderfully. Picks up stations on all bands although it really shines on the AM Broadcast bands.Too bad there is so little music on AM these days. I did find a Port Angels WA station that plays oldies from the 30 and 40's. This radio really is quite loud, fills my whole (small) house with rich, warm mellow tones. My only small concern is the rotating lighting mechanism that displays the currrent band selection is a little off sync. It doesn't always illuminate the proper broadcast/police/overseas window after I switch the band dial. I may look into this but I'm good to go.
Thanks to everyone. Next project, the little Detrola.

Great ! Glad to here you got her running again. I've got the same problem here near Phila no music stations. If your set has a phono input you can hook a mp3 player to it. Or you can use a signal generator to make your own little broadcast station. Guess what you get to be program manager!
Terry