Model 60 volume and no frequency - Printable Version
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RE: Model 60 volume and no frequency - Roger Cole - 04-09-2014
Rich,
This is the best photo I have on hand right now. To be honest, this was the most confusing part of the recap. I tried to label the parts, and I pray I didn't make a mistake. I have my detailed notes at home, and I will double check later.
Make sure the right bakelite capacitor bank is restuffed correctly. The physical layout seems backwards compared to the layout on the schematic.
I find it helpful to make an enlarged copy of the schematics and trace everything out with colored pencils. As a verify each connection, I highlight it. That gives me some confidence that I have things wired correctly.
RE: Model 60 volume and no frequency - winston763 - 04-10-2014
Thank you again guys. I am very appreciative that you give me this help. My ebay book is on the way. I need to absorb the last 2 posts especially. it can't be today but hopefully tomorrow. It says a lot about you and this site that you'd give me this much help with nothing to offer you back. for one, I am going to open up that block capacitor to 42 and 75 and if I didn't do something wrong there. Thanks! Rich
RE: Model 60 volume and no frequency - winston763 - 04-11-2014
Roger/Steve, well I had wired the bakelite cap 8035-D wrong and the illustration showed me the correct way. Now I have volume control but it only plays the putt-putt of motorboating. I had the tuning capacitor at 460 hz and found I could "tune" the motorboating on the back 2nd I.F. to higher frequencies and faster or no sound. I still cannot inject a audio signal but I put the alligator clip on my am test radio and the tone is loud and clear. I have Joseph Carr's Old Time Radios and I see there are several possibilities. At least I have sound and something resembling a "known" problem. I think that's progress thanks to you. Thanks, Rich
RE: Model 60 volume and no frequency - Roger Cole - 04-11-2014
Rich,
Yes, that is definitely progress.
If you still can't inject audio, you still have some issues on the audio section. Take a close look at the tone control. The 0.01 uF should always bypass to ground, and the 0.015 uF is a switchable bypass to ground. If the wiring is off, you may be grounding out your audio signal here.
This may be a stupid suggestion, but when you are trying to inject audio, what "modulation percentage" do you have dialed in on your signal generator?
One quirk of your signal generator is that the output power switches on the right only apply to RF output. The audio output power is controlled by "AF MOD/OUTPUT" control. Just for kicks, if you have a cheap AM radio laying around, try injecting some audio into the speaker and output transformer to make sure it is working the way you expect.
Roger
RE: Model 60 volume and no frequency - winston763 - 04-12-2014
the eico 324 is a recent buy that I recapped and made a cord from a cable and connected red/black alligator clips to the end with one side having the .022 cap in series. the signal comes out loud and strong but I believe only thru the Eico not the cord. Clipping it to the working radio seems to make the signal stronger but it maybe only because I ground it. I can tune out the motorboating but I can't find any frequencies adjusting the trimmers. i'm sure that exercise is just a random stab in the dark. I received the book How to Repair Old-time radios and I really like the approach. this will help me with missing background information. I've reviewed the possible "open" capacitors and can't find any. I checked the tone wiring and it think it's correct in that it grounds for both settings and the tone works. I am getting "radio air" but no stations. Maybe one of my resistors was replaced with the wrong value? Rich
RE: Model 60 volume and no frequency - Roger Cole - 04-13-2014
Rich,
If you are certain that the tone control is wired properly and there are no obvious problems in the audio section, the next place to look is the power supply. Make sure the polarities are correct for the electrolytics and that all of the connections are correct. You really should be able to feed some audio signal into the audio section of the receiver.
If all else fails, make a clean copy of the schematic, get out your colored pencils, and trace the entire thing. As I go through a radio I mark each section of the schematic as I verify that it is connected as it should be. I also check values for every resistor, capacitor and inductor and mark the schematic accordingly. It helps enormously to be compulsive, patient and systematic. If you have a wrong resistor, you should be able to find it.
I wouldn't play too much with the trimmers until you are ready to align the set. It only takes a small turn to really mess up the alignment and make life more difficult down the road. The only way to align the set is to be able to feed RF and IF into the circuit, and it doesn't sound like you are at that stage yet. Don't worry. Trace out the schematic, verify each connection and component, and you will be there soon enough.
My Philco 60 was rather touchy with the alignment. First, the tuning capacitor on my set is quirky. You can turn the dial and move the plates past the point at which the capacitance actually changes. To avoid this, I had to make sure that the dial pointer hit 1500 kHz before the capacitor reached the plateau point. Once I did that, I could align the RF section without much difficulty. Second, it made a big difference to clip a lead to the AVC line and use that voltage as my adjustment point. I usually attach my oscilloscope across the secondary of the audio output transformer and adjust from there, but it wasn't giving great results. After some reading, I saw where several people had better luck using the AVC line for alignment, and I had much better success with this method as well. This may become my new standard protocol.
Keep plugging away at it, and don't get discouraged. There will come a point where music will come out of your set, and believe me, it will be some of the sweetest music you have ever heard.
Roger
RE: Model 60 volume and no frequency - winston763 - 04-19-2014
Roger thanks for the encouragement. I hope you're reaching the end of your 60 adventure. This radio had the electrolytic capacitors with both negatives going to the wire wound resistor (47). I see different wiring for nearly every example I find on the internet. I checked my Eico on a Firestone and it worked fine. Somehow I must be grounding the audio as you said - although I can tap the 1 meg resistor and the block capacitors and hear the tapping loud and clear. another thing I did was rewire the antenna - I probably did that wrong. I saw on one of your posts where you wired it correctly. I have followed the resistors and checked my recaps and I can't find the problem there. Maybe I should stay in the 40s and 50s where it's much simpler but I sure like these cathedrals. You are correct, when I hear a station from this radio I will yell loud enough for you to hear in in your living room! Rich
RE: Model 60 volume and no frequency - winston763 - 05-02-2014
Help, I tried the forum's tuning method but my cheap analog multimeter doesn't work on the speaker. I can clip my signal generator to the end of my antenna line and tune it to a station. The signal generator frequency is tuned to the same station as a modern AM radio. I turn off signal generator and nothing is on the air. The speaker is loud when i accidently touch my multimeter to the wrong point. I don't own an oscilloscope and i've been over the schematic for weeks. Anyone have a hint at what i'm missing. I must be close? Thanks, Rich
RE: Model 60 volume and no frequency - TV MAN - 05-03-2014
You need to have to get a more sensitive meter to read anything off your speaker. When I am aligning and testing, I use my Fluke 77 digital meter. It reads less than .5 volt depending on the setting of the volume control and generator. I find about .150 or so A/C is about what I can stand without going insane listening to it. I ususally set the gen and volume control to about that level, then you can adjust from there. I didnt used to think the meter was that important, I had ears, ok... Yes, well, that meter can see flutcuations and things that my ears cant hear. It is a good help. If you are going to do this kind of work, I reccomend a decent digital meter. My preference is a Fluke. They are easy to use and forgiving of user error.
Dont feel too bad - I am fighting an intermittant. Read the last page or so of my post on the 70 rebuild. You are blessed in that you have a definate problem rather than one that comes and goes. Hang in there.
RE: Model 60 volume and no frequency - Roger Cole - 05-05-2014
Try aligning it to the DC voltage on the AVC line. Using my cheap Radio Shack voltmeter I ended up with better results than using my oscilloscope at the speaker when I aligned my 60. That was my first attempt at using the AVC voltage for alignment, and it worked really well. Just be sure you are in DC mode, and be aware that the voltage should be negative. Adjust so that the voltage is as big a negative number as possible.
If you think you are way off, start by feeding audio on a 460 kHz carrier into the cap electrode of the 78 tube and adjust the trimmers for the second IF transformer. You should be able to get a reasonable amount of tone out. If that works, move the signal input to the cap electrode of the 6A7 and adjust the trimmers of the 1st IF transformer. From that point on, you can go back to Ron Ramirez's procedure.
Roger
RE: Model 60 volume and no frequency - winston763 - 05-08-2014
Roger and Tim, I tried the AVC method. I maximize the negative DC then tried to find a station, nothing. I went and bought a Fluke 87 from an electrician. He was kind enough to give me pointers. I used the Ron Ramirez's procedure. I got sound and values so high I had to keep turning down the volume. when I tried to get a station, nothing. This has been my money pit and I've spent late night's for nothing. I feel like I have to put this on the self as I'm out of options right now. Maybe I have to take a fresh look at it later. I don't know why I can get so much sound at 460 Hz but nothing else. Thanks for all the help and patience but I need a break from this one. Rich
RE: Model 60 volume and no frequency - TV MAN - 05-09-2014
Dont give up on it. Sometimes if you set it aside and think about things a little, you get a fresh start, but dont let it go too long or your may forget what you have or havent done. Notes are real nice. I have been fighting an intermittent since last march. I think I finally have it found, but if it decides to work, then you dont really know for sure.
I am asuming you are talking about the IF alignment. If you are injecting the signal at the beginning of the IF stage, then that means that part forward is working. Connect the gen to the antenna, can you set your generator to a station signal, such as 800kc, and tune it. Do you get anything?
RE: Model 60 volume and no frequency - Roger Cole - 05-09-2014
You're getting close, but sometimes it helps to set things aside for a little while and then come back to it.
Stupid thought here. One detail I ran into was the adjustment on the variable capacitor. There is a small bolt which comes up from the bottom and has a nut soldered to the thread end of the bolt. This lets you turn the bolt by turning the nut. Mine was old and hard to turn, and before I knew it, the nut had come loose from the screw and instead of actually moving the trimmer cap, it was just moving the nut up and down the bolt. I doubt this is the issue, but it was a complication I hadn't seen before.
Don't give up. You will eventually get it working.