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Im a little further along on this.
Tube 42 was no good, After replacing tube 42 I had a low hum then touching the screen cap got a loud buzz.
I bought a EICO 320 on E Bay I had to do some work to it. When setting up the signal generator I was able the get a tone from 6A7 screen cap.
Question here is it gave me tone no matter where the generator dial was.
All the coils check out except IF transformer I get 49 Ohms instead of 85 Ohms
Any ideas what I should be looking for? It's a run 7 the last run made.
Thanks, Ralph
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Hi Ralph,
Looked up a EICO 320 schematic. I see it's a tube model. Personally, all my test equipment is newer, transistor based as opposed to tube based. A little bit more reliable.
1st off, turn the output of the RF gen way way down, then feed the signal to the grid cap of the 6A7.
2nd, according to Rider's book on how to align Philco radios, if your RF Gen has a cap in line with the output of the generator you should place a 500 ohm across the output of the generator to provide DC bias to the tube.
Also, what kind of test equipment do you have? do you have an oscilloscope? a Frequency Counter? a high Z meter to monitor the audio output tone?
I was lucky when I recently restored my Run 7 Model 60, I had bought a second one off of ebay for parts, funny thing was it was in better shape than the unit I was planning to restore! LOL, so scrapped it cause the chassis and cabinet were shot. Those transformers in the metal cans have mica caps in them, both had open coils so I swapped them out and replaced the hidden mica caps. I am not sure if I wrote down what I measured on those coils, will have to look when I get home.
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Hi Ralph. First, lets make sure the Eico sig gen is working well. I, myself, use an Eico 324 Signal Generator...
[Image: https://64.media.tumblr.com/a5460038db65...867b95.jpg]
They are great for this kind of work, far more forgiving than the modern transistorized ones. First let's check it on the AM broadcast band. If you have a modern radio with a digital frequency dial, which you know is pretty accurate, this will be very easy, if not, use the analog radio you have which has the most accurate dial. Take a piece of wire about 10 feet long and wrap it around a small cardboard tube leaving about a foot free. Strip the end of this free part. attach the signal line (inner conductor) of the RF OUT cable to this stripped end. If yours is original it should have something like an alligator clip on both this and the braid (outer conductor) of this cable. Now, let's check the accuracy of your signal generator first.
Turn on the sig gen and let it warm up for at least 15 minutes. Set both the audio attenuator and the RF attenuator about halfway. Set the range switch to range B. Tune your radio to a station whose frequency you know down near the low end of the dial, below 700 KC if possible. Now tune the sig gen to that frequency and above and below it, and see how close it is. Do the same up near the high end of the dial, just below 1500 KC. This will allow you to verify if the sig gen is working, and how accurate it is.
Once you determine that it is accurate, set the radio dial for 920 KC. This is exactly double the IF frequency used in the model 60. Now, switch the range on the sig gen to A, and tune it to around 460 KC. Go up and down a little but until you get the strongest signal through the radio. Now you know the signal generator is putting out a sound modulated 460 KC signal, and can then align the IF on your model 60. I generally work my way backwards, feeding the signal into the IF amp tube first and aligning the 2nd IF transformer, then going to the mixer tube, and sending the signal in there to align the first IF transformer. I leave it there, and go back and forth a couple of times to make sure they are both peaked.
I use a good, accurate digital readout radio which covers from the AM broadcast band up through 30 MC to double check frequencies the signal generator is putting out every time when I am doing an alignment. When connecting to the grid cap of a tube I use a 100 mmF condenser in between the signal generator center conductor and the grid cap.
I hope these suggestions are of help. I'll keep an eye out for this thread and do my best to help if I can.
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Hi Guys,
I tested the EICO 320 from what I can tell is working fine.
On all of these tests below it did not matter what station the radio was on.
On tube #78 I got tone @ 155KC, 233KC, and 445KC
On tube #75 Hum on all of A band 150-445KC
No sound on 6A7. I'm still rookie at this and not sure what to look for next. I understand there are a couple of mica caps ( can I replace mica caps with an axial capacitor) under one of the can's I haven't figured out how to disassemble this can.
Thanks, Ralph
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OK, first connect up the signal generator to put out just an AUDIO signal, cable connected to the AUDIO OUT Jack. Turn it on. put a .1 MFD cap on the center lead of the cable, and ground the braid to the radio chassis. touch the other end of the cap to the plate terminal of the #75 tube socket (pin 2). With the radio on and warm, this should inject an audio signal into the circuit at that point. This will let you check the #42 tube and audio output circuits. You should hear the audio tone from the signal generator.
Next touch this end of the cap to the cap of the #75 tube. Again you should hear the tone.
Now switch the probe connection to the RF out. Set the sig gen to 460KC with AF modulation. Change the cap on the output of the probe to a .001 MFD. Leave the shield connected to chassis.
Connect the other end of the .001 cap to the plate terminal of the #78 tube (pin 2). You should hear the tone. Adjust cap #26 until tone is at its loudest. This sets the 2nd IF transformer.
Next switch the capacitor connection to the plate of the 6A7 tube (pin 2). Adjust capacitors #18 and #16 for the loudest tone output. This should align your IF.
I find the Rider's information actually better for aligning these receivers, so here is a link to those pages on Nostalgia Air. This is a pretty good scan, and you should find the information it gives on alignment useful, so read all the pages.
http://www.nostalgiaair.org/PagesByModel...013793.pdf
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Ralph, If you are hearing the IF signal when you connect your signal generator to the cap of the 78 tube but not when connected to the cap of the 6A7, there must be a problem between those stages. You should hear a loud 460 kc IF signal when connected to the 6A7 grid cap.
I would first check the IF transformer between the 6A7 plate and 78 grid for continuity. Both the primary and secondary windings should read less than 100 ohms. If the primary is open, you will have no plate voltage on the 6A7 and therefore hear no signal. Check the voltages on the 6A7 tube pins and compare to the typical readings given in the service info.
Don't worry about replacing mica caps until you have checked the other possibilities. Micas are pretty reliable and rarely need replacement.
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Today nothing is happening with the radio. I decided to take a close look at #25 second IF transformer and found nothing wrong. After putting it back together I still had no sound not even static.
So I jumped the gun and replaced mica cap #13 blue, brown, yellow the parts list names it .00011uf so I replaced it with 100pf. Then I got a shock from resistor#10 (forgot to discharge electrolytics) 51K That's when I see the resistor has been cooking. Is that because of the 100pf or I have a short someplace?
Thank you for all your help, Ralph
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Well I have it running really good on 1 station 2 others come in faintly. Thanks for the help I'm good with the 1 station. Its the one I listen too.
I bought an old Superior Instruments TV-II tube tester I can't find a Schematic for it. There is a Philco 34-8003-10 condenser in it. Does anyone know what it is?
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WOW that was quick. It's a great help. At the same show I picked up a Philco G681-124 I don't have a schematic for that either. Do you have a way to get that?
Thanks again for the promptness, Ralph
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