[mikethedruid]

Tonight I sat back in my living room and listened to the Red Sox game on my Philco on FM. I noticed a slight microphonic tendency, barely noticeable , but there if ya know what to listen for. I went about tapping things from the top of the chassis and the FM-1000 and the Z300 caused thumping when I tapped them hard. I pulled the chassis again, and re-soldered a number of solder joints, shiny or not. That solved the problem and now the FM is really stable as well as loud enough. Well, I had the pleasure of listening to the last three innings of the game on the 48-482, clear, stable, and great sound. Even the Red Sox losing in the 9th has not dampened my pleasure.

The real lesson here is perseverance. I would not be satisfied with performance I knew was not up to the standard Philco would have demanded of a set, even with their built in antenna. I found that those who told me the antenna works well were absolutely correct, it does. Of course, I also was slapped with my own fallibility. I suppose I am getting old, but the condenser I miss-connected was one I remember I had clipped one end of.. then... when I went to put the new one in I do remember puzzling a bit. In the end I must have connected it one off. LOL. However, checking, checking, and checking again I finally found the problem and fixed it. I also know the new components I installed should keep the radio running well past my lifetime.

I have laid in a complete reserve set of tubes also. I never liked loctal sets. This is the first one I have restored. I much prefer octal tubes. Part of my prejudice stems from the fact that for a long time the loctal tubes were hard to find. With the internet, it is actually easier for me to get them now than it was years ago. The octal pins also provide more contact area in the sockets. I have a few hundred tubes in my stock, but I didn't have any for this set, and had to buy them all. Luckily, I got some good deals on eBay.

When you really go through this radio and do it right, it turns out to be a powerful performer. The tuning of the Z300 unit is a bit tricky. The alignment procedure gets one only so far. If you notice in the FM Alignment Notes, note 5 explains the way to do the alignment without a signal generator. This is, in fact, the best way to do the final tweaking of this unit. It takes a steady and delicate hand, and requires tiny adjustments to first the coil, and then the cap, and back again, until you reach the optimum performance. Once you get it right, the performance is remarkable.

Thanks again to all those who have helped and encouraged me. You made it a lot easier and more fun.

[Michael]

I just acquired a 48-482 myself. I have been recapping it. I am finding tubes, but cannot find an FM-1000. Do you have any thoughts? I would change the tube socket if necessary. I am guessing that I may well be SOL.

Michael

[klondike98]

Michael, Welcome to the Phorum!! 

Try Bob Dobush at FindATube.  He has an FM1000 in his listing so he probably has one.  I've bought tubes from him in the past.

[mikethedruid]

I was very fortunate in that my FM-1000 was good. I also found a spare on ePay for a reasonable price. You find them there too now and again, but you have to keep looking.

[Michael]

Thanks for the help. The findatube did not have an fm-1000. The place that said it had the tube, where I ordered two, called and said they could not find one. On the bright side, After replacing two known bad tubes, It is working on AM. I live in a home sided with aluminum and we have a metal roof. I can barely get our in town station without and outside antenna. While tuning up the 48-482 I discovered a station I had never heard before. It was 100 miles away. This was with chassis out and the internal loop disconnected. Gad, They really knew how to design a radio back then. I would like to get the fm band working, but I will live without it if I cannot get the tube. I put in new dial lamps. I was tempted to use LEDs like I do on everything else. I realized the colour would never come out right. I am sticking with incandescent. I will keep checking on ebay. I keep thinking of the history this radio must have had. What news programs played through that old speaker. I have not yet aligned the dial. The service manual has a picture of the dial which I will print out to exact scale. I will then tape it onto the dial background and align the frequencies. The voltages all check out according to the manual. I have not even used a scope on it yet. I cannot understand why my portable transistor radios can barely get our local station here. I would think that my one expensive transistor radio that is good for shortwave would at least work as well as this old Philco. I would assume that in 66 years, there would be great design improvements. Go figure.

This radio seems to have no AGC. Tuning in a strong station results in overdriving the audio. The volume control then works to correct this. I do not see a feedback path in the print. Am I missing something? Let me know if you any knowledge of this.

Thanks Again,

Michael

[Ron Ramirez]

The findatube did not have an fm-1000.

Did you ask Bob if he had any FM1000 tubes? His website lists the tube as being available either NOS for $6 or used for $3:

https://docs.google.com/spreadsheet/ccc?...0foD#gid=6

You can buy used tubes with confidence from Bob - if there is a problem he will make it right. The only time I ever needed an FM1000, I bought one from him - no problems, the 48-482 I was working on turned out very well.

[LASJayhawk]

This place says they have them as well.
http://www.vacuumtubes.net/Prices%20F123...QV04-7.htm

But unless the filament is burned out, or the tube is missing I kinda doubt it is the problem. I have had more issues with bad silver micas in the front end. I have also had problems with the 7F8 converter tube as well. They will work fine on AM and SW, but won't oscillate at the frequencies required by FM if weak.

[Michael]

Well, I got an FM1000 that works. Everything is recapped. I have an FM sensitivity close to 1 uv. I am amazed. However, so far, I cannot get the AM receiver to work. Pushing the right hand button gets me FM. It is not marked. Pushing the FM button, 3rd from the right, gets me nothing. I will have to really study the print. I think I will use one of the station buttons next and see if the AM works at all.

Michael

[Mondial]

Michael, I think your buttons are mixed up. The button furthest to the right should be labeled FM. The next one toward the left is SW and the third is BC (AM).

Make sure the mechanical linkage between the main bandswitch and the front end bandswitch is properly adjusted. Pressing the FM button will activate it and it should return by spring loading in all other positions.

[Michael]

Thanks, so much for the info. Those knobs come off easy and I guess someone got them mixed up. I will put them back properly. I want to test the radio with it out of the case. I am planning to wind a coil to emulate the one built in to the case. I will also print out a dial face from the manual. I have only replaced the tubes that tested bad on my Sencore tube tester. It does work nicely in FM. I have not been able to figure out where the AM band was until you told me. I plan on spending a lot of time aligning it to perfection. At least I will try.

Michael

[Michael]

Well, even when I got the push buttons sorted, the AM still did not work. I spent a lot of time trouble shooting it. I was obviously out of practice. I quit working on the problem for about two weeks. During that time it occurred to me that if FM and SW were working then the problem is most likely the LO for AM. I checked it and it was not working. I found that the factory, YES the factory had introduced a defect that finally killed this radio. They had place the bare wire from a 1/2 watt resistor pressed against the AM  LO coil. This finally wore through the thin enamel insulation. You can see this from the picture. I simply pulled back the bare wire and the AM jumped to life. Now I need to align it for frequency on the dial. I will use a frequency counter for this and a calculator that can subtract 455 from my counter reading :-)

Michael

[Image: https://www.dropbox.com/s/t5ixn9sd9lhvkk...0784sm.jpg]

[mikethedruid]

For alignment follow the instructions in the Philco repair bulletin. You don't have to do any subtraction. Just follow the instructions carefully.