Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
I'm at the point where everything I touch turns to s**t! 
I've got a simple Airline model 4705 . Just a simple 6 tube AM radio. Replaced all caps. Tubes and resistors checked OK. Alignment done. Everything is fine except I only get one station . It is WGN, 720 from Chicago (about 40 miles away). It comes in on any dial position.  It is just as strong at 55khz as it is at 1600khz.
Any clues as to where to start?
Thanks guys,
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 1,412
Threads: 72
Joined: Oct 2007
City: Linn Creek, MO
Sounds like the oscillator is not working. Have you tried placing another radio near it to see if you can pick up the oscillator?
Steve
M R Radios C M Tubes
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Well Steve, I just checked it. The oscillator is working, but now WGN is gone and the only thing I can pick up is my SSTRAN set at 1500khz. This would be a step in the right direction except that it is coming in at about 700khz no matter what I do to the osc trimmer on the tuning cap!
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 1,412
Threads: 72
Joined: Oct 2007
City: Linn Creek, MO
Eric, when you listen to the oscillator on the other radio and adjust the trimmer, does it move up and down the dial?
Steve
M R Radios C M Tubes
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Eric, do you have a signal generator? A very nice piece to have to troubleshoot these problems.
jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Sure do, Jerry. I was able to do the IF alignment.
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Great Eric, now use it to run AM frequencies into the antenna input but please use an Iso trans on the radio. As you know, this has a potentally hot chassis depending on the plug orientation. Steve is much smarter and there is something wrong in the RF/OSC section. See what you find for a "tone" across the AM band.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
Posts: 1,562
Threads: 56
Joined: Nov 2008
City: Sedona, AZ/Placentia/CA
Sorry, Dup. And sorry Eric if I didn't realize and recognize your experience and knowledge. Best, Jerry
A friend in need is a pest! Bill Slee ca 1970.
(This post was last modified: 09-22-2015, 09:48 PM by jerryhawthorne.)
Posts: 16,510
Threads: 572
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
>>>I'm at the point where everything I touch turns to s**t!
Eric, go save Midas 
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 4,896
Threads: 54
Joined: Sep 2008
City: Sandwick, BC, CA
Schematic linked to is an Air King 4705, not an Airline, or is your set actually an Air King? If so try replacing the 22k Ohm resistor on pin #1 of the 12SA7 tube. The 22K resistor, or R3, may test fine cold, but may not when the set is powered up.
Regards
Arran
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
Yes Arran, it is an Air King. The 22k ohm resistor is on pin #3 of the 12SA7 tube. It goes from pin #3 to ground. I replaced it. No change, except now it is motor boating.
No big deal. It is time to put it on the punishment shelf  and go on to something else.
Thanks for your help,
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 4,442
Threads: 419
Joined: Jun 2011
City: Boston
State, Province, Country: Massachusetts
I think as a kid I wound up on that shelf. I read a story/interview with a guy who worked at Air King, trouble shooter and supervisor on the line and while they did make some decent stuff they did cut some corners. It may be that some manufacturing may not be to spec or done well to begin with. Sometimes taking a break is good, think about it, work on something else for a change.
Good luck.
Paul
Tubetalk1
Posts: 825
Threads: 113
Joined: Aug 2012
City: The Villages
State, Province, Country: Florida
I think we all ended up on that shelf at one time or another  It's just that if this keeps up it looks like I'm going to need more shelves!
Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org
Posts: 2,353
Threads: 92
Joined: May 2010
City: Clayton, NC
This could be the result of an alignment mis-adjusted to an harmonic of the frequency vice the frequency itself. Also, how do you verify that the F is what it should be.
Posts: 2,353
Threads: 92
Joined: May 2010
City: Clayton, NC
What I mean is do you verify the frequency from your sig gen with a frequency counter?
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Model 70 Cabinet Trim
|
| musar ,
Well if you have any more questions feel free to post away .
Sincerely Richardradiorich — 08:56 PM |
|
Model 70 Cabinet Trim
|
| Although I have not made any cabinets or cabinet parts for a couple of years, I still have some parts left over, includi...Steve Davis — 06:26 PM |
|
philcorepairbench.com - shadow-meter
|
| Thanks Ron.fenbach — 02:43 PM |
|
Model 70 Cabinet Trim
|
| Thank you, Gary. Before making my original post, I had clicked on "Steve Davis Cabinets" only to find that it...musar — 02:25 PM |
|
philco predicta
|
| Welcome to the Phorum, cgl18! I am not your resource for television repair, but lots of friendly help is available here...GarySP — 02:12 PM |
|
Model 70 Cabinet Trim
|
| Welcome to the Phorum, musar! You can send Steve Davis a private message (PM). The site is at the top of the Home page...GarySP — 02:09 PM |
|
Model 70 Cabinet Trim
|
| How do I contact him? The only contact information for him I could find when searching online was a telephone number th...musar — 10:38 AM |
|
philco predicta
|
| Hello, good afternoon, I would like to ask what the possible problem could be if I don't have an image on the screen. I ...cgl18 — 10:19 AM |
|
Philco model 38 code 121 not receiving signal.
|
| So one last question before I finish this radio. Regarding the speaker and output transformer. I salvaged the original o...Stormlord5500 — 09:31 AM |
|
462ron
|
|
It’s on the bottom of the homepage of our Philcoradio.com homepage!
Ron462ron — 07:20 AM |
|
Who's Online
|
There are currently 1071 online users. [Complete List]
» 1 Member(s) | 1070 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
