I picked up this old guy at the auction.
http://www.flickr.com/photos/53710524@N06/10141888325/ It's a 1924 Crosley Trirdyn. Three tube that do the work of five. The circuit is a regenerative reflex. Anyway it seem like a interesting project and I think the price was about what the three good 01A's cost.
When I got it home I gave it a cursory checkout and found that both audio transformers are open. After a little research I found that AES sells the winding part of the transformer without the lamination. So the repair of the transformer just requires disassemble the laminations slip on the new core reassemble and it's done.
Also one of the tube sockets was broken. I used some epoxy to fix it. I do have a backup plan if the epoxy doesn't hold up, one of the Phorum member was kind enough to make one available to me.
Tomorrow I'm going to order the parts to rebuild the audios in this old guy. It also needs some serious cleaning!!
Here's the info on this set:
http://www.crosleyradios.com/battery-sets/TRIRDYN-1.pdf
Terry
Neat!! Will be interesting to see how it goes tuning your set once it is working. I have never owned a regen set but understand that you are always close to making your set go into oscillation and turning it into a transmitter.
I think that regens offer the best bang for the buck. That's what Powell Crosley was all about. You will be amazed how well a little two or three tube regen will pull in the signals. The little Crosley 51 two tube set will give good volume with a speaker on local stations and plug in the fones and listen to the DX stations.Just using 6v,22v,and 45v batteries. A lot of the performance is do to good design.
Terry
That is really cool! .. One day I hope to be good enough at repair to fix a set like that. You guys amaze me sometimes. Any shot you could post some photos of the job and explain it to us newer guys?
Actually generally the older battery sets are simpler to repair. Most are TRF sets (tuned radio frequency). A series of RF amps usually 2 or 3 ( these are all tuned to the same frequency amplifying the signal from the antenna), a detector stage, (turns rf signal to an audio signal) and two stages of audio amplification (take a weak audio signal and makes it loud enough to drive a speaker).
There's no frequency conversion, no lo, no IF stages. Much easier to align. The Trirdyn is a little tricky as it uses 3 tubes. 1st tube is the rf amp, 2nd tube is the regenerative detector, and the 3rd tube is the audio amp. Now for the tricky part reflex. If you look at the schematic you will see audio transformer #6 that is feeding the audio signal back to the 1st tube the rf amp.What is happening is the audio signal is being amplified again by the rf amp tube. One tube working as two tubes pretty tricky!!!
More later when I dig into this set.
Terry
Ordered parts a week ago but haven't seen them yet. Will post when I'm working on it.
Terry
Hi Guys
The parts came in the other day but I've been busy. Did get a little done on it.I took one of the audio transformer off the chassis and then took it apart.
http://www.flickr.com/photos/53710524@N0...otostream/ It's very important to mark the connections so you know whats what. Once I got it apart I realized a couple of things. 1. The original winding was pretty corroded and was green.
http://www.flickr.com/photos/53710524@N06/10390923294/ 2. The replacement winding was much smaller than the original.
http://www.flickr.com/photos/53710524@N0...otostream/ It was about half the length but the important part is the hole in the center(the window) It was just right at 1/2x1/2" 3. The core comes apart very easily and I wouldn't have to take lamination's apart one by one the E and I plates.
http://www.flickr.com/photos/53710524@N0...otostream/
Replacing the winding itself was very easy once I got it apart. Really just slide the old one off and the new one on. The only thing I had to think about was making the proper connection to the screw terminals. Will take some pics of it all together didn't have my camera handy when I do the second one.
Tnx for your interest
Terry
Keep 'em coming. This is very interesting. It's great to see one of these old sets being worked on.
Well both transformers are repaired and reinstall into the set. I measured the resistance of the windings though out the set and it all looks good. This thing is really dirty! It has this black crap on it that seems the make for bad connections. I may have to take this thing apart and clean it all to get it to work well. Anyway the only other thing I found that needs to be replaced is the grid leak resistor. Pretty common problem on older sets.
Terry
Grid is probably the only thing where leak is a good thing to have
Placing a modern 1-3 meg resistor in place of the original grid leak should be an adequate fix until an original item can be obtained.
Well I did a little cleaning on the set the other night. Most of the time after work I'm kinda bushed and crapout in the recliner. Took off the strip that has connections for the batteries and gave it a little scrub and add some white to the lettering to make it a bit more readable.
Today I got home early from work about 2pm. I was thinking my little Trirdyn need a power source. Am thinking of using batteries at some point but for testing and servicing I like an AC supply. You have to be concerned about the batteries going weak while you are working on it. Dug around and found a few of the basic parts. Two hours later I had this:
http://www.flickr.com/photos/53710524@N06/10464766754/ And
http://www.flickr.com/photos/53710524@N06/10464765725/
Still in the testing stages, it's making about 215vdc So I think I going to add a little series resistor to drop voltage down a bit. I only need 90v and 22v. I used a power resistor with a slider so I can pick off any voltage I need by just moving the slider. It's like a pot. Actually it has two sliders, very handy so I can pick off the 90 and the 22vdc. Still have to mount up a off/on switch an a terminal strip on the back for the wires to terminate to. Have to run to the store to get a few parts. When I get this done I can put power to the Crosley and is what's what.
More Later
Terry
ps Here's the Diagram for the Power Supply:
http://www.flickr.com/photos/53710524@N0...otostream/
It's pretty basic!! PS. was on pain killers and drew the diodes backwards!!
That black wire coming on the left that is stripped and almost touching the metal.....is it 110V?
I put in a little time in the power supply tonight. Mounted and wired up the line cord and off/on switch. Added a regulator to the filament supply. Mounted and wired that too but need to find a 5K pot for the voltage adjustment and a terminal strip.
Terry