05-05-2013, 12:49 AM
Nice work, judging from the pictures. I have a 41-280 that has the separate dial light for each band as shown in the Riders schematic I got years ago from another restorer. All of the other 1941 Philcos I have seen use a single bulb in a hinged holder as you describe. I can only assume that the difference was a cost-saving mid-production change.
I can't believe you wove your own grill cloth. I've never heard of any restorer doing that before.
I don't think you can do much of value without your IF and detector tubes. If you have an oscilloscope you might be able to confirm that your oscillator is putting out near the correct frequencies (high impedance probe on Osc XXL plate or maybe on cap #31 if you have the same 41-285 schematic numbering I do.) With a scope you might also confirm antenna coil and push button operation with a probe at the grid of the 1st Detector XXL. But most of your troubleshooting and alignment will need to wait until you have a full tube set.
You can also carry out basic troubleshooting steps to confirm the final amp functioning by touching the plate side of cap #52 (coupler between plate of 1st audio 7C6 and grid of 41s) with an operating soldering iron and listening for the loud hum from your speaker, but if you can hear any hiss or slight hum with the radio on, this test is probably unnecessary.
My experience with those darned ON/OFF switches is that they are very prone to failure after all these years, but unless you are just itchin' to work on it, I'd leave it in until you need to replace it somewhere down the line. Several people including yours truly have posted methods for replacing the switch. Ron improved on mine. You can search on my screen name to find out what I did and how he improved it.
It was common enough once for people to have service people install a phono plug and switch that would inject the phono signal into the 1st amp circuit, so you could do something similar for your iPod, but I'm not really sure how to do it on this radio. Some people like to short or otherwise disconnect the oscillator so that all of the radio signals are cut off to eliminate interference with the phono (iPod) signal. I've read advice from others about matching impedences, so if you search the forum for "iPod" you can probably find it.
Marcus and Levy ("Elements of Radio Servicing", 1947) have some diagrams how to put in a phono plug and switch into a radio of that vintage, so that might be a good place to look to begin with. The book is available to download for free as a series of pdfs on the Antique Radio Forums. Look in Chapter 12, "Detector Stage -- AVC." (Different editions might have different chapter numbers, but that's what it says in my copy.) Again, impedance matching could be necessary, so search for that advice.
I would not replace the power transformer wires without a good reason. YMMV. Those cloth-covered wires are likely very stiff, but if you don't move them too much their insulation will hold. I looked into replacing some once, but there are so many fine wires I could mess up, that I decided not to.
I can't believe you wove your own grill cloth. I've never heard of any restorer doing that before.
I don't think you can do much of value without your IF and detector tubes. If you have an oscilloscope you might be able to confirm that your oscillator is putting out near the correct frequencies (high impedance probe on Osc XXL plate or maybe on cap #31 if you have the same 41-285 schematic numbering I do.) With a scope you might also confirm antenna coil and push button operation with a probe at the grid of the 1st Detector XXL. But most of your troubleshooting and alignment will need to wait until you have a full tube set.
You can also carry out basic troubleshooting steps to confirm the final amp functioning by touching the plate side of cap #52 (coupler between plate of 1st audio 7C6 and grid of 41s) with an operating soldering iron and listening for the loud hum from your speaker, but if you can hear any hiss or slight hum with the radio on, this test is probably unnecessary.
My experience with those darned ON/OFF switches is that they are very prone to failure after all these years, but unless you are just itchin' to work on it, I'd leave it in until you need to replace it somewhere down the line. Several people including yours truly have posted methods for replacing the switch. Ron improved on mine. You can search on my screen name to find out what I did and how he improved it.
It was common enough once for people to have service people install a phono plug and switch that would inject the phono signal into the 1st amp circuit, so you could do something similar for your iPod, but I'm not really sure how to do it on this radio. Some people like to short or otherwise disconnect the oscillator so that all of the radio signals are cut off to eliminate interference with the phono (iPod) signal. I've read advice from others about matching impedences, so if you search the forum for "iPod" you can probably find it.
Marcus and Levy ("Elements of Radio Servicing", 1947) have some diagrams how to put in a phono plug and switch into a radio of that vintage, so that might be a good place to look to begin with. The book is available to download for free as a series of pdfs on the Antique Radio Forums. Look in Chapter 12, "Detector Stage -- AVC." (Different editions might have different chapter numbers, but that's what it says in my copy.) Again, impedance matching could be necessary, so search for that advice.
I would not replace the power transformer wires without a good reason. YMMV. Those cloth-covered wires are likely very stiff, but if you don't move them too much their insulation will hold. I looked into replacing some once, but there are so many fine wires I could mess up, that I decided not to.
John Honeycutt
