01-26-2014, 09:53 AM
Eeeeeeeekkkk!
Well, I replaced the 'lytics in this beastie, at least the ones in the PS unit. I connected things back up the way the last 'tech' had them, just to see if anything would work.
I got good B+ to everything, but connecting an output transformer to the proper connections gave no love. So, I had to open up the tuner chassis to see what was up with the output section. When I did, I got a big surprise... the ugliest kludge of power resistors and lytics I've ever seen... all just hanging there in midair. :/ I have no idea what all that carp is, I'll have to try to figure it out. I couldn't find my shop camera tonight, so I'll have to post some pics of the mess tomorrow.
I did find the reason there was no audio out of the transformer: This tuner has a huge transformer mounted on the back of it. I had no idea what it was for till I opened the bottom, but once I had done that, I saw that it was a high fidelity audio output transformer. I had thought it to possibly have something to do with the phono input, but nope. It's connected to the 6L6's. Connecting a speaker to it gave me sound, but very distorted sound. Replacing the coupling caps to the driver stage cleaned it up, and it sounds great. I still want to try to put it all back to stock if I can, but at least I know it does make radio noises.
Work to do.. total recap.
Additional work to do: SW is virtually deaf, likely in need of a front end alignment, though everything seems to come in on the proper frequencies.
FM isn't deaf, but neither does it track properly. It tracks high on the low end, and low on the high end, and that with the LO trimmer set to minimum capacitance. So, gotta figure that out, too. Also, though it's not deaf, the RF amp section does zilch. This could be a dead tube, since it seems to be an odd tube, and isn't used in any other bands.
AM... that's fantastic. I hear stations I've never heard before on there, and the fidelity/bandwidth switch is great. Gonna love it when I get this thing all up and running. Once I do, I'll have to get to work on that 45MHz FM transmitter I promised Ron I'd design, so I have something to listen to on the FM.
Well, I replaced the 'lytics in this beastie, at least the ones in the PS unit. I connected things back up the way the last 'tech' had them, just to see if anything would work.
I got good B+ to everything, but connecting an output transformer to the proper connections gave no love. So, I had to open up the tuner chassis to see what was up with the output section. When I did, I got a big surprise... the ugliest kludge of power resistors and lytics I've ever seen... all just hanging there in midair. :/ I have no idea what all that carp is, I'll have to try to figure it out. I couldn't find my shop camera tonight, so I'll have to post some pics of the mess tomorrow.
I did find the reason there was no audio out of the transformer: This tuner has a huge transformer mounted on the back of it. I had no idea what it was for till I opened the bottom, but once I had done that, I saw that it was a high fidelity audio output transformer. I had thought it to possibly have something to do with the phono input, but nope. It's connected to the 6L6's. Connecting a speaker to it gave me sound, but very distorted sound. Replacing the coupling caps to the driver stage cleaned it up, and it sounds great. I still want to try to put it all back to stock if I can, but at least I know it does make radio noises.
Work to do.. total recap.
Additional work to do: SW is virtually deaf, likely in need of a front end alignment, though everything seems to come in on the proper frequencies.
FM isn't deaf, but neither does it track properly. It tracks high on the low end, and low on the high end, and that with the LO trimmer set to minimum capacitance. So, gotta figure that out, too. Also, though it's not deaf, the RF amp section does zilch. This could be a dead tube, since it seems to be an odd tube, and isn't used in any other bands.
AM... that's fantastic. I hear stations I've never heard before on there, and the fidelity/bandwidth switch is great. Gonna love it when I get this thing all up and running. Once I do, I'll have to get to work on that 45MHz FM transmitter I promised Ron I'd design, so I have something to listen to on the FM.
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