12-27-2015, 08:22 PM
I didn't like the look fo that plastic wire I had made the speaker harness from, so I ordered #20 cloth over plastic in white, and, with the help of some green acrylic paint, colored one wire green, and left white stripes on another, and the third all white, so they basically match the colors listed on the schematic. I then installed them. I also made a little piece of micarta board using inch and a half square pieces of calligraphy parchment and 2 part, 5 minute epoxy. It is easy enough. On a piece of scrap paper mix up the epoxy. Then on a piece of wax paper place a piece of parchment. spread epoxy on the top, and stack on another piece. Carefully press out any bubbles and spread again, and put on another piece of parchment. Keep stacking to the desired thickness, but don't spread epoxy on the last sheet. Let it dry well, overnight at least. I used this to make the insulator to rebuild the dial lamp. First I traced the lamp socket, and carefully nipped down the micarta until it was just outside the line. Then using the point of my Exacto knife, I drilled a little hole right in the center of the little circle, working from each side alternately, just big enough to slide through the conductor of the wire I was going to use. Once the wire was through I looped the end tightly and flat against the insulator, and soldered it into a little blob. this is how it came out.
[Image: http://41.media.tumblr.com/e9518bb565b39...1_1280.jpg]
so, I have progressed to the point where I can begin testing. First I connected the speaker back up. Then I tested things with only the dial lamp and 6 volt tubes installed. No explosions, no "hot" smells, and the light burned nicely. Next I installed the 5Y4G. No sound from the speaker. I look at the speaker and see one of the voice coil wires has come loose from the little connection for it at the bottom of the output transformer. I correct that, and try again. This time I have some hissing from the speaker, which changes in sound when I touch various grid caps, and rises and falls nicely with the volume control, and varies in tone with the tone control. It seems things in the amp are basically working. I have B+. Nothing is drastically wrong under there. Tomorrow I shall continue, but I am quite happy so far. Here are a couple more pics, one of the whole underside of the chassis as it stands now, and the other of the chassis and speaker on my bench turned on.
[Image: http://40.media.tumblr.com/8b950cb601923...2_1280.jpg]
[Image: http://40.media.tumblr.com/1115100c9d04e...3_1280.jpg]
I am still using the old dial until I get to the final stages of alignment. Don't want to crack or scratch the new one ! So, that's how it stands tonight, tune in again for further adventures...
[Image: http://41.media.tumblr.com/e9518bb565b39...1_1280.jpg]
so, I have progressed to the point where I can begin testing. First I connected the speaker back up. Then I tested things with only the dial lamp and 6 volt tubes installed. No explosions, no "hot" smells, and the light burned nicely. Next I installed the 5Y4G. No sound from the speaker. I look at the speaker and see one of the voice coil wires has come loose from the little connection for it at the bottom of the output transformer. I correct that, and try again. This time I have some hissing from the speaker, which changes in sound when I touch various grid caps, and rises and falls nicely with the volume control, and varies in tone with the tone control. It seems things in the amp are basically working. I have B+. Nothing is drastically wrong under there. Tomorrow I shall continue, but I am quite happy so far. Here are a couple more pics, one of the whole underside of the chassis as it stands now, and the other of the chassis and speaker on my bench turned on.
[Image: http://40.media.tumblr.com/8b950cb601923...2_1280.jpg]
[Image: http://40.media.tumblr.com/1115100c9d04e...3_1280.jpg]
I am still using the old dial until I get to the final stages of alignment. Don't want to crack or scratch the new one ! So, that's how it stands tonight, tune in again for further adventures...