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Another 48-482
#1

Some of you may remember my first postings on this Phorum when I was restoring a 48-482, which turned out rather well in the end. Well, over the years I have acquired two more complete with cabinet, and another chassis with the buttons and knobs. I figured it was time to begin work on another one.

Here is a picture of the top of the chassis before any work. It's a little dusty, but all there and in respectable shape.
[Image: https://64.media.tumblr.com/559189791d8a...159238.jpg]

Here is a picture of the first work done one it. I replaced the line cord, but have not connected it since I have to replace the condensers in the bakelite block first.
[Image: https://64.media.tumblr.com/87fac7f5c1c5...6ca773.jpg]

I measured the physical size of the two electrolytic condensers so I can try to order something suitable as a replacement, otherwise I will have to do as I did on the last one, and mount terminal strips inside the chassis to hold separate electrolytic condensers since the two are multi section. This should keep me amused for the next couple of months.
#2

I removed the bakelite block with the input condensers and rebuilt it with safety caps. I then reconnected it along with the new line cord...
[Image: https://64.media.tumblr.com/0830dbcded44...85ab65.jpg]
#3

A 48-482 was just the third radio I restored and it sounded very good when finished. I was fortunate in that I did not have to do much aligning. I was also fortunate that I found some cloth that was a good match for the grill cloth. I have some left over if your cloth is in bad shape. My notes are at https://www.dropbox.com/s/70wmoe1juujiue...s.pdf?dl=0
#4

Thanks, Bob, There is a "whiskey rayon" grill cloth they sell on eBay which I used on the first 48-482, which I like very much on it. It is not an exact, or even very close match, but looks as if it could be. Here's a picture of the first one I restored...

[Image: https://64.media.tumblr.com/d640415209ad...2_1280.jpg]
#5

Got motivated tonight to start replacing the paper condensers, starting with the hard to get at ones under the rotary switch and the push button tuners. I figured to get these out of the way since they are the most obstructed and difficult to replace.

[Image: https://64.media.tumblr.com/b0e795e4f309...df4729.jpg]

[Image: https://64.media.tumblr.com/6edb7e02dbca...258f99.jpg]

And, with the push button tuners back in place...

[Image: https://64.media.tumblr.com/4d186529a0a4...2dbc5a.jpg]
#6

Looks great!
Icon_thumbup
#7

I am continuing to replace condensers while I wait for the electrolytic can types I ordered, along with some yellow poly ones to add to stock. Last night I replaced one paper, and one single section electrolytic...

Before...
[Image: https://64.media.tumblr.com/31c7eebac784...1c79a1.jpg]

After...
[Image: https://64.media.tumblr.com/0bcee4ef1178...e8303f.jpg]
#8

I continued to replace condensers today. Unfortunately, I will have to stop for a couple of days until my order from AES arrives because I have run out of -01 MFD condensers. Between the RCA and this radio I have gone through a drawer FULL. LOL ! Icon_lol 

[Image: https://64.media.tumblr.com/033bc8c45f0d...6c3106.jpg]
#9

HOORAY ! Icon_e_biggrin  Today my order from AES came in, and I got back to replacing paper condensers. I finished replacing everything in the area which is obscured by the output transformer, and then put that back. Now I just have one corner left to do, but it has a lot of paper condensers, some of which are quite buried, so I will have a nasty chore there. Here is a picture of all the condensers in the area I replaced since my last posting, and then with the output transformer back in place.
[Image: https://64.media.tumblr.com/be95bc13c845...e45bc5.jpg]

[Image: https://64.media.tumblr.com/5f2dcd66f92b...4285ca.jpg]
#10

All done with the paper condensers, and I replaced the 2 section electrolytic. Last I have to replace the 3 section main electrolytic filter condenser, which looks to be something of a pain. I will have to keep all the leads going to each section separate and marked so I can put them back appropriately on the replacement. Good close up pictures are a BIG help. That is the last before initial testing though, thank goodness.
[Image: https://64.media.tumblr.com/87fb4d701a55...d16fad.jpg]

[Image: https://64.media.tumblr.com/ef9c9a23d89a...ab9d2a.jpg]
#11

Condenser work ALL DONE ! Icon_e_biggrin  Replacing the 3 section main electrolytic went smoother than I expected. It helped that there was sufficient extra length on all the wires going to it that I could just cut off the soldered ends and re-strip them to install on the new condenser. A Dremmel tool with a carbide cutting disc made short work of the soldered on outside lugs. The new condenser fit perfectly, and re-soldering it went very smoothly. It turned out a lot easier than I had expected ! So, this is what it looks like with the new condenser installed. See above for the before picture.
[Image: https://64.media.tumblr.com/04ee17453345...6d8e9f.jpg]

Now, I am going to make me a mint julep to celebrate. Icon_e_biggrin
#12

Later last night I continued to work on the 48-482. I replaced both the dial bulbs, which was something of a job. Both bulbs were quite stuck in their sockets, and the socket assemblies were very difficult to remove from the back of the dial plate, things are quite cramped back there, especially on the tuning condenser side. I ended up having to loosen the dial plate, and then put it back, but eventually got both bulbs replaced, and the sockets lubricated with a little of my gun oil mixture. (50% 10X30 motor oil, 50% Marvel Mystery Oil) I also lubricated the shaft bearings of the tuning condenser and dusted off the plates of it with a little brush. It now tunes smoothly all up and down the range. Finally I replaced all the tubes. NOTE WELL ! There is an error in the paperwork which is not well noted, Where the paperwork says a 6SQ7 goes is actually a 7B6 !  This threw me the first time I restored one of these radios, but I remembered it this time.

Well, that was it. Time for the first test. I plugged the set in, and it came to life. No smoke. No loud noises. Both good signs. The dial bulbs came on fine. soon a hum came from the speaker. All good signs. I pushed in the Broadcast Band button, and began to tune up and down the band with my test antenna connected to one of the antenna terminals. I could hear faint stations in several places on the dial. I tried Shortwave, and heard nothing but slight variations in the background hum and hiss. Then I tried FM, and got nothing but the background hum.

I turned the radio off, and unplugged it again, and sprayed the whole push button assembly well with contact cleaner. I went up and down the row of buttons pushing each one in turn about a dozen times or more. I then let it dry out for an hour or so, and tried it again. BCB was far less noisy, and more stations came through, still without what I know is normal volume. Shortwave was still quite dead, although there was more noticeable variation in sound as you tuned up and down the dial. FM came to life. There were quite a few stations which came through clearly, and at what sounds like normal volume. No distortion, just sounds FINE. FM is working as it should, which will save me a LOAD of headache.

So, that's where it stands now. Next I will begin to chase back through the circuit and see why the BCB and shortwave are not up to snuff. That should be pretty straightforward. The fact that the FM works fine pleases me. It also means I don't have any problems with the audio amplifier circuits. I suspect the problem lies in the IF for the AM / SW which is 455 KC, and is separate from the 910KC used fore the FM.. Although they appear to use the same IF transformers, they are tuned separately on those transformers. We shall see.
#13

After a thorough alignment of the AM this radio is VERY good ! Last night I finished aligning the AM; first all the IF, then the oscillator tuning and the RF until it was working as well as it could on the standard tuning, picking up stations all up and down the dial. Since much of the alignment called for the signal coming in through the loop, and the chassis was out of the cabinet, I made a substitute loop. For anyone who comes after this thread, here is how I did it. It may prove useful to you also.

First I measured the loop in the cabinet. It was 18.75 inches by 10.25 inches, so each turn was (18.75 + 10.25) x 2 inches in circumference, or 58 inches. There were 3 complete turns, for a total length of 174 inches. I had a box that was 6 x 6 inches, for a total outside circumference of 24 inches. 174 / 24 = 7.25, so 7 and 1/4 wraps around the box would equal the proper length to emulate the loop. I used some 20 gauge insulated wire, and made the simulated loop, and it worked a treat ! I figure a similar process would work for other Philco radios which have those big loops of thick, bare, copper wire at the back of the cabinet. You will need to measure carefully so you can calculate the total length, then find a suitable form to wind it on, and wind on the exact length. I also left about 8 inch leads to connect to the antenna terminals. You can see the loop to the right of the radio chassis in the picture.

[Image: https://64.media.tumblr.com/453b2cb82755...08b7c7.jpg]

Once I had the AM alignment (and the SW) all done, and double checked the FM, I then set all the push buttons to stations I listen to a lot on the broadcast band, WSM 650, WLW 700, WSV 750, WLS 890, WRVA 1140, and WLAC 1510. The stations come in as well on their push button as they do with standard tuning. The picture above was taken today of the radio playing on FM. In the daytime the reception on AM in my radio room is not great, terrible actually, because of the interference from the TVA power lines, but the FM comes in clear, and with stations all up and down the dial. I am VERY pleased with the results ! Only one thing; I now realize that there is still a problem with the FM on the first 48-482 I restored. It should be a LOT better than it is, so I may go back and hunt down what that problem might be.
#14

Thanks for the tips on these radios! Now I can only find one that doesn't have the speaker grill cloth and cone ripped to shreds! I swear, Ohioans did strange things to Philcos....

No matter where you go, there you are.
#15

mikethedruid, your 48-482s are really nice. I thought I would ask you about alignment of my 48-1270 since they are pretty much same chassis (as you pointed out in our posts a while back). I got pretty good results with AM and SW alignment and now I'm finally motivated to do the FM. In the FM procedure it calls for inserting "a length of wire or flattened solder between the ceramic form and the edge of the trimmer plate." I understand the goal is to reach the top of the C303D padder. I've never opened up an IF can so I'm not sure exactly where to start inserting the wire or how far I need to push it in. There is a little slot next to the C303D trimmer screw. Is this where the wire should be inserted? About how far? Also the FM procedure is long and tedious - are there some shortcuts I should know about lol?




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