The PHILCO Phorum

I bought a couple of the "David Winter" FM modules     FM Converter for vintage radios (paleophonies.com)     to experiment with. I'm going to install the first one in a Philco 118.
FM Conversion Module by Steve Davis, on Flickr

I have been using this 118 chassis with no cabinet in my shop for many years, it just sits on a shelf with an H-13 speaker.

Philco 118 Chassis by Steve Davis, on Flickr

FM Conversion by Steve Davis, on Flickr

The first step has been completed, replacing the electrolytics with film capacitors. I had restored the chassis several years ago, it still works well. The past few years, I have been using film caps to replace electrolytics so, I decided to do that upgrade.

This is a four section 1uf 1uf 1uf 2uf. Since this cap is clamped from the top, I cut that end (done previously). A piece of 1" PVC pipe fits the inside of the can snuggly and is used to hold the cap on the can. I am using "orange dip" film caps.

Philco 118 by Steve Davis, on Flickr

Philco 118 by Steve Davis, on Flickr

Philco 118 by Steve Davis, on Flickr

The main filter caps were done a little differently. I cut the bottom ends off and made nylon plugs to replace them. 
Philco 118 by Steve Davis, on Flickr

Heat shrink tubing was used to insulate the connections from the can.
Philco 118 by Steve Davis, on Flickr

Philco 118 by Steve Davis, on Flickr
Philco 118 by Steve Davis, on Flickr

I want to use the band switch for switching the FM so, this will require a new switch with more poles and 3 positions. Coming next.

Steve

Steve

Are you also going to manufacture a new/additional dial?

Mike, graphics is not my bag. There may be three or four FM stations that I might listen to, I will probably just take note where they appear on the AM dial.

Steve

In my area you might be able to pick up 3-1/2 FM stations during the daytime, more depending on the receiver. Even so the content really isn't better then what's on AM broadcast. Any FM set around here needs a good RF amp and a decent antenna to do better.
Happy Christmas
Happy New Year
Arran

Back in the 70's I had a FM converter attached to my AM car radio. Had it's own dial and connected through the antenna. Didn't work too bad considering it was a one speaker mono unit. Take care and BE HEALTHY! Gary

Hi Everyone, I have 3 of the old fm convertors used for cars with their own power supplies and wiring. I use them on my 40-190, 42-355, and 42-380 Philcos and my RCA C15-3. They work very well.

Hey Gary

Back about '75 or so I had one in my '56 Beetle. It had an old tube radio I think it was an Automatic brand set with a vibrator p/s . Carried 2 6v car batteries one each side under the back seat to power this 12v accessory. Later on I gutted the radio and mounted the FM tuner inside. Built a several watt audio amp and a nice little FM set w/no vibrator BUZZZZZZZZ in the background. Oh the fm set was a SparkOmatic. Think I bought that thing at Zayres. I haven't seen one those 20+ yrs

Gary, Willy, Terry - what Steve is talking about is a very different animal from the old school FM converters.

You can see more info about this module here:
https://antiqueradios.com/forums/viewtop...2&t=405154

The modification will require a 7 pole 3 throw band switch. I bought an 8 pole 5 throw switch on eBay (I have since found a 9P3T that would be a better choice). The new switch will need some modification.

I drilled and tapped the front plate and installed a stop screw to limit the travel to three positions.

 Adding FM to a Philco 118 by Steve Davis, on Flickr

The shaft diameter is 6mm and about 1/2 inch long and will need an extension.

Turning the shaft extension.


Band Switch Shaft Extension by Steve Davis, on Flickr

Using lathe to mill flat on the shaft.
Band Switch Shaft Extension by Steve Davis, on Flickr

Finished shaft extension.
Band Switch Shaft Extension by Steve Davis, on Flickr

Hello Steve,
Nice Job so far and my last radio that I was restoring for my self my Zenith model 908 I also used film capacitors .
The 1950s GE clock radio that i restored the chassis for I used standard Electrolytic capacitors .
Sincerely Richard

P.S. one tool I see you have is a lathe that one tool i would like to add to my collection of tools .

Hi Richard.
If you want a lathe, I say get it! I wish I had gotten one years ago, after having one, I would never want to be without it.  If you do decide to get a lathe, PM me, I may be able to offer you some tips.

Steve

The new band switch has been mounted in the chassis and wired. The radio is working on AM and shortwave though it may need the alignment touched up. The next step will be installing the FM module.

Adding FM to a Philco 118 by Steve Davis, on Flickr

Adding FM To A Philco 118 by Steve Davis, on Flickr

Hello STeve,
Nice Job with the Wafer switch I need to find a replacement one for my Eico 147a signal tracer .
Sincerely Richard

The FM module has been mounted to the front wall of the chassis. All connections have been made, I used small shielded cable for the audio.

Adding FM to a Philco 118 by Steve Davis, on Flickr

The module requires 6.3 to 16 volts AC or DC with one side grounded to the chassis. The Philco 118 uses 6.3 volt tubes but, the 6.3 volt winding has a grounded center tap. This is a problem. One half of the winding could be used with a voltage doubler circuit. I looked all through my "someday kit" and could not find a suitable capacitor to make the doubler. But, I did find about a half a dozen of these nice little 12 volt, 150ma transformers, so I decided to go with one of them.

Adding FM to a Philco 118 by Steve Davis, on Flickr

The open circuit voltage of the transformer is 16 volts, right at the high limit of the module. With a 150ma transformer and only a 24ma draw from the module, my fear is, the voltage might not come down much from the 16 volts. I decided to remove a few turns from the secondary winding. I disassembled the transformer and unwound 80 turns then reassembled the transformer. The OC came down to 10 volts, good enough.

Adding FM to a Philco 118 by Steve Davis, on Flickr

The transformer has been installed.

Adding FM to a Philco 118 by Steve Davis, on Flickr

The ground connector is never used on this radio so, I converted the original ground connector to the FM antenna connection by drilling the hole larger and using the insulating bushing from a parts chassis. 

Adding FM to a Philco 118 by Steve Davis, on Flickr

It's time for the test. The first step is to calibrate the tuning, this is really simple. With the radio turned on, the band switch is set to the new FM position. The dial is turned to a point near the low end of the scale, the calibrate button is gently pushed and released. Now, the dial is turned to a point near the high end of scale and the calibrate button is pushed again. That's it, the radio is ready to tune in FM stations and tune in FM stations, it did! All I can say. This thing is awesome! Stations come in crystal clear and the sensitivity is excellent. Using a wire about 2 1/2 feet long for the antenna, it picks up 30 or more stations across the dial.

Some thoughts and observations

The module uses one section of the radio's original tuning capacitor to select stations so, to keep the AM working, some sort of switching arrangement is needed to switch the tuning cap and the audio. This could be as simple at a DPDT switch or maybe a DPDT DIP relay mounted directly to the tuning cap. I chose to replace the band switch to keep all switching on one control. The AM did require realignment. The tuning cap wire to the module needs to be as short and direct as possible. One of the first things I noticed was any movement of the chassis would cause the FM to go off station. The shadow meter had to be removed to access the trimmers for the AM alignment. While on FM any movement of the detached shadow meter would cause Fm to go off station. Turning the chassis over I could see the shadow meter wires were rubbing the tuning cap wire to the module. I never used the SM because lamp socket has been damaged so, I just removed the SM and wiring and adding a resistor. I also used hot glue to immobilize the tuning cap wire. This totally eliminated all problems with the tuning. The next thing to do is create a log to locate the FM stations. There may be 5 or 6 stations that I might listen to, I will note where they appear on the AM scale. I will continue to use this chassis as is in my shop, I also plan to modify another radio for use in my house. To anyone thinking about doing this mod, I highly reccomend it.

Steve