I recently bought a Philco 40-190 Art Deco cabinet because it was beautiful and cheap. ($25.00) The only thing missing was the radio itself. So I decided to find and install a radio to make it complete. I was able to find an untested 40-150 model that appears complete. Now, I have the bug to get the radio in working order.
I am an electrician by trade and learned Electricity and Electronics while in the US Navy. I don't know much about radios but I'm confident I can learn.
My first question is about the 40-150 schematic. They label certain components "Cond." and a uF symbol. I realize that they are "capacitors." My queztion: does Cond. mean "condenser?"
Looking forward to meeting and talking with you all.
Thanks,
Kevin
Kevin,
Welcome.
yes, "cond" is condenser which is the capacitor in the old parlance.
"uF" is "microfarad". Respectively "0.01uF" is "10nF" and so on so forth.
read up on the typical old tube radio restoration routines.
This 1940s radios used rubber-coated wires that may or may not become brittle and devoid of insulation, so you might have to replace some or even most of the wiring inside the chassis. if however the wire feels soft and pliable, you could live it alone.
All the capacitors except the mica type if present, should be replaced. Paper and electrolytics.
Resistors should be verified and those way out of tolerance replaced.
Tubes checked.
Speaker and the output transformer verified for integrity.
Then you could check the transformer (actually do it first to know if you even want to proceed with the chassis as a transformer is fairly expensive), put the tubes in, plug the speaker in (do not run without speaker) and power up.
Thanks for the advice. I haven't had a chance to look closely at the chassis but I suspect that I will have to replace several parts.
Any leads on a used Cap tester and tube tester would be appreciated.
You do not need a cap tester.
You simply need to replace all the said caps. No testing. The old ones are tossed. If you are really into a authentic restorations, you could save shells and re-stuff them with new ones, but few people do that (I do).
And the micas are better left alone. If you need to test them a DMM with a capacitance metering capabilities is all you will need.
A tube tester: depends on what you will get (or maybe you already have one). A mutual conductance types are recommended; simple emission measuring ones are not enough.
Hickok made good ones; myself, I have their 600A.
Once you get it, a manual is pretty good, and then you can ask here if you don't understand something.
Hi Kevin and welcome,
Did your 40-150 come with the back panel to the cabinet? Mounted on it is one of the two loop antennas you'll need to get it to operate. There's a smaller one mounted in the top of the '150 cabinet for the top SW band.
Thanks for the advice! Good idea changing ALL the Caps. (except the Mica)
No cabinet back panel. Near as I can tell, I have the original speaker, a "Tube" antenna that swivels and another small one under the top of the cabinet. Am I missing any parts? Please advise.
I did a little more research to find that you should be ok. My concern was that the two different sets used loops that aren't compatible and that would be a problem. But both the '150 and the '190 tune the same frequency ranges on each band so should be usealbe. Figuring out the wiring of it may be a bit of a trick but your an electrician so it's just another day at work...
The 40-150 is a table model so it uses a 6" speaker but the opt is mounted in the chassis on both sets, no worries abt moving it around. Most of the time the original ones are bad (open pri) it may need a replacement or have a replacement.
Thanks for looking into that for me
The 6" and 12" speaker should have the same ohm rating, right? The connector is the same. Is the output transformer different for each model? It hadn't occured to me they might be so different. They certainly look the same.
So many questions!
>The 6" and 12" speaker should have the same ohm rating, right?
Probably not but I would loose any sleep over it. More than likely the opt isn't original so it's not going to be a perfect match to the 6' spkr. Generally the small Philco spkrs are abt 1 ohm and the larger ones are abt 2-3 ohms. The replacement transformer will probably be a better match than the original.
I have a question for those of you more experienced in restores. I see on my schematic the filter caps are 12uF and 16uF. When I look the radio I found those disconnected and two 40uF caps being used. The changes looked professionally done and the solder looked original. I don’t see any updates. My question is if you were doing it which values would you use?
As a rule, I usually replace caps with what is shown on the schematic. In some instances I have heard of increasing the value of the caps when attempting to reduce hum. I personally do not have the expertise many of the members here do to know just how much to increase the filtering. When in doubt, ask, or replace with documented values is my motto. Take care and BE HEALTHY! Gary
The 12 uF cap connected to the rectifier tube cathode is somewhat critical in that it should not be drastically increased over what was originally specified. The capacitance in this location affects the peak current drawn by the rectifier tube each AC cycle and a much larger value can exceed the tube's peak current rating. A larger value also will tend to increase the DC voltage output of the power supply. With today's higher AC line voltages, you really dont want the DC output increased even more.
As far as the 16 uF cap after the field coil, its value is not critical and a larger value here within reason will reduce hum without any negative effects. The 40 uF in that location would be ok.
If I was replacing the caps, I would probably go for 15 or 16 uF for the 12 uF and 20 or 22 uF for the original 16 uF. Keep in mind the original caps had very loose tolerances on their capacitance, typically -10% to +80%, so the original 12 uF could have ranged from 11 uF to almost 20 uF as installed by the factory.