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my 41-81T The radio itself... - Printable Version

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my 41-81T The radio itself... - mikethedruid - 10-12-2014

I have begun to work on my 41-81T. One of the first things I noticed is that they seem to have worked the actual loop antenna into the case of the radio itself ! Also, there is a connector on the side of the radio that must be for attaching an external antenna and ground. Attached are pictures showing what I see. Has anyone else ever worked on one of these ? Does anyone have any information on these antennas? I find this a very interesting solution to the antenna problem in a portable.

[Image: https://33.media.tumblr.com/afff5c3544fc8bf01b57f2fe6ff0845e/tumblr_ndbq6lJubq1sqxsgyo1_1280.jpg]

[Image: https://38.media.tumblr.com/ec110d8f61a328f2749f1502a62ba9bd/tumblr_ndbq6lJubq1sqxsgyo2_1280.jpg]

This is the beginning of the thread for the restoration of the radio itself. I have made a separate thread for the making of the battery pack for it, so those interested in batteries can find it there, and not have to wade through all the chassis work. This part may be idle for a bit while I get the battery pack made. I wont be able to test my work on the chassis without it. Stay tuned....

RE: my 41-81T The radio itself... - mikethedruid - 10-20-2014

Well, I finished making the battery pack for my 41-81T, check the thread for that part of the project to see how I did it. Having made and double checked the battery to make ABSOLUTELY SURE all the pins were connected correctly on the socket, I then tested all the tubes in the radio. The 1A7G tested very good. It was a Sylvania tube, and may be a replacement. The other three tubes were all Philco and appear original. All three, the 1N5G, the 1H5G, and the 1A5G all tested marginal. I put the tubes back, and decided to go for it, see if the old girl had any life left in her as she is. I plugged in the battery, and turned on the radio. After just a few seconds I could hear a little crackle as I turned the volume control. I then tuned across the band and found that the radio received all the local stations just as it stands, despite the three weak tubes !

I will be taking out the chassis and replacing the two paper caps, and the one electrolytic next. Stay tuned for that adventure.

RE: my 41-81T The radio itself... - Raleigh - 10-22-2014

I had two problems with those spring connectors for the external antenna. Evidently the two-part contact was intended spring together to make good contact when no external antenna was connected but then break the connection with the internal loop when the external antenna was plugged in. Kind of like a crude version of today's phone jacks that disconnect a speaker when a headphone is plugged in.

The first problem was that they were bent enough not to make good contact with the internal loop. I wasn't able to bend them just right to make good contact, so I soldered in a jumper wire to the base of them to make the contact. I don't intend to use an external antenna, so that solution was alright with me.

It looks like a previous owner of your radio had the same problem, since there is solder joining the two pieces together.

The second problem was that those contacts were long enough to scratch the cardboard of my battery when I installed or removed it. I partly solved that by shrinking a piece of clear heat shrink tubing over the contacts and cutting it off just long enough to cover the metal.

The heat-shrink still scraped against the battery when installing and removing, so I decided to cut a piece of thin but fairly stiff plastic to shim the battery away from those antenna contacts. I hold it against the battery when I install it to isolate the contacts from the cardboard.

I'm sure no one cared much about scraping the cardboard when those batteries were new, but I wanted to protect mine.

RE: my 41-81T The radio itself... - mikethedruid - 11-14-2014

Well, I have finished with the electronic restoration of my 41-81T. I replaced most of the rubber covered wiring despite the fact that it is not dry rotted and is still flexible. I replaced all the wires that go through the chassis to the grid caps, and all the wires in the battery harness, as well as the leads that extend from inside the chassis to go to the antenna built into the case. I did leave those rubber covered wires that were buried inside the chassis under other wiring if they were in good shape. I replaced all the capacitors. The radio did play OK before I began any work, and now it plays even better, I think. From my work bench in my cellar in Providence, RI, I can pick up WGN in Chicago, and WOR in New York on just the internal antenna ! Here are some pictures of the chassis showing the work, and what the radio looks like from the back all finished.

[Image: https://38.media.tumblr.com/e9791d5b79518c5dff6f98e101e36168/tumblr_nf0frxT0K61sqxsgyo1_1280.jpg]

Before restoration top of chassis

[Image: https://33.media.tumblr.com/dd2f17929f60f2f971c7ff97c6828775/tumblr_nf0frxT0K61sqxsgyo2_1280.jpg]

Underside of chassis before restoration

[Image: https://38.media.tumblr.com/e2c3645d6f81f83698a592e4c6424590/tumblr_nf0frxT0K61sqxsgyo6_1280.jpg]

Underside of chassis after restoration

[Image: https://38.media.tumblr.com/ae563e7508ddcce7783a5ba5cf5f6ead/tumblr_nf0frxT0K61sqxsgyo7_1280.jpg]

What the radio looks like inside now that it is finished and working.

I still have to fix the leather handle for the cabinet, but that does not belong here, but in "cabinet restoration" so I won't go into it here. That will be the easy part though. All the hard work is done.

RE: my 41-81T The radio itself... - Ron Ramirez - 11-14-2014

Congratulations! Icon_thumbup