Working on Philco 46-350 radio
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Joined: Jul 2011
Using the test point mentioned in the schematics for the 48-360, I tested voltage behind the R12 (2,200 Ohm) resistor which originally connected to the AC/DC switch and it read 163 volts! This seemed way too high so I used another meter and got the same voltage. I believe this is the voltage you mentioned that should be around 80/90 volts. I then moved my positive lead to pin 2 of 3Q5 (the brown wire that goes to the can capacitor) and got 0 voltage. This is the one that's suppose to be around 8.5 volts.
I get no sound out of it at all, btw.
Posts: 22
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Joined: Jul 2011
I think I found a potential problem (my fault). When I put in new resistors, I replaced R11 (900 OHM) by taking the wires away from the old resistor and installing a new resistor. The old resistor is hidden behind some bar of sorts that riveted in the case so I can't see exactly how it's connected and the schematic isn't very clear on this. I decided to try and not take it out and go a different direction instead. R11 looks to be interconnected with R13 somehow which is a 65 Ohm resistor (also behind the bar). By me taking this resistor out of that circuit, I broke its connection with R13.
What exactly do the connections look like inside the rail so I can correct this OR How do I remove the rail without messing anything up?
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Joined: Oct 2008
City: Merrick, Long Island, NY
This part is called a candohm and there is no reason to replace it unless it is open or shorted to the chassis. It is a multiple tapped wirewound power resistor and will get quite warm when the set is on. If you put it back the way it was you should be fine. The voltage will go down quite a bit when this load is applied. In addition to supplying the B+, this setup also provides the filament voltage (8.5 volts)
Again refer to the model 48-360 on Nostalgia, because the diagrams are much clearer, and the two sets are nearly identical. On that diagram the candohm contains R100A, R100B, and R100C.
When it is all back together, the set should be brought up slowly using a variac this time with the tubes in it. You can monitor the filament voltage as you bring it up. Do not let it go above 8.5 volts. If the voltages are still too high, you may have to add another power resistor at the beginning of the chain (before R100A) The line voltage was a lot lower when these sets were designed.
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We're getting really close! I just heard stations through it for the first time in probably many years!
The tuner works and the volume control works. One major issue though is that the volume is extremely low. At its highest, I have to put my ear up to it to hear it. When I turn it down, I can't hear anything about halfway down.
I am SO close to getting this thing in running order and I owe it all to you guys. Thanks so much!
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Ok, I was able to get one of the stations in pretty loud and clear by adjusting the fine tune screws but it's the only AM station that comes in. Something wrong with the radio or just crappy reception?
Here's a video of my radio working:
http://www.youtube.com/watch?v=6vFT0TojHZI
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
OK, you need to make sure that the tuning capacitor is not shorting. One by one disconnect and use ohmmeter to test all three sections from full open to full close. If there is a short, there might be a bent fin (rotor) that is contacting the stator. Since you are getting reception on the high end or the band, I think this might be the problem.
But if you are testing this in your basement, and there is only one or two local AM stations, bring the set upstairs.
Since you have changed so many components, you probably need to have an alignment done as well. Check to see if there are any locals who would have the equipment to help you do this.
Posts: 347
Threads: 34
Joined: May 2007
City: Raleigh, NC
Out of curiosity, how did you replace the can capacitor? One of my 46-350s had the same problem as yours. The metal just fell apart when I took it out to restuff it.
I ended up wiring modern 'lytics rated 160 volts into the radio with leads dressed as if they were in the can. I left them sticking out of where the can was, with a tie wrap around them to hold them together. This was so I could finish restoring and testing the radio.
Once the radio was working, I used PVC pipe and a stiff sheet of clear plastic to make a closed cylinder that is almost the same dimensions and looks very much like the restuffed original in my other 46-350. I sprayed it with ACE hardware metallic paint, and took the attachment points from the damaged original and screwed them into the PVC cylinder. It won't pass a close inspection, but it is better than modern 'lytics hanging out of the hole.
John Honeycutt
Posts: 22
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Joined: Jul 2011
Ok, first a reply to codefox:
I unhooked everything and tested the fins on the rotor against the fins on the stator on each section and very slowly turned it and got no continuity so that's good. I turned on another radio in the house and checked the AM stations on it and it also didn't receive stations on the lower bands so I''m thinking maybe it's just a reception issue.
To Raleigh:
I found a modern replacement for it on Amazon. I will say that your method is probably easier and cheaper to do but I wanted to go a little more "proper" on mine so I bought a replacement here: http://www.amazon.com/CE-Manufacturing-4...B004HGU9L8 . The can is the exact same size as the original. The problem with this (besides it being slightly expensive) is that instead of it being the type with the negative wire, the can itself was the negative so I had to find a way to insulate it from the chassis. I bought a phenolic plate made for these cans and did some modifying to the chassis to make it fit and bolted it in there. I cut a couple of holes in the chassis for two of the four negative leads to fit down in (big enough so they wouldn't touch the chassis) and two small holes to bolt the plate on. The result is as you see in the photo.
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Joined: Oct 2008
City: Merrick, Long Island, NY
Seems like you could use an alignment which try to find a local person to do this for you. There are a lot of AM stations still on the air, and they are easier to receive during the night. Your set is also directional, meaning that rotating it physically will change it's sensitivity in regards to a station you wish to receive. An external tuned loop antenna works wonders with this set.
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Joined: Jul 2011
If I ever find a local person that works on old radios, I will ask them about it. Thanks.
Posts: 22
Threads: 1
Joined: Jul 2011
My dad knows someone that works at the local radio museum. They know how to tune radios there and they told me that I had it tuned in pretty well and that it didn't need messed with.
I've already replaced the leather strap with a sufficient one from a belt kind of like the original so I'm confident in saying this project is done in my eyes.
Thanks for your help everyone and your patience in helping a newbie with this.
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