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: 1,411
Threads: 71
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: 1,411
Threads: 71
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: 16,533
Threads: 573
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: 4,908
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: 4,460
Threads: 423
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
|
|
Philco 42-345 Restoration/Repair
|
| Hi, all the caps I order, other than the electrolytics, are of the 630V rating. No worries on it being too high, and no ...gary rabbitt — 05:46 PM |
|
Philco 42-345 Restoration/Repair
|
| Hi, there's a lot to consider when designing these circuits so you shouldn't have a lot of concern when replacing caps. ...RodB — 02:03 PM |
|
Philco 42-345 Restoration/Repair
|
| I have ordered and received new caps for this radio and hope I've ordered the correct ones. I tried matching them to the...osanders0311 — 11:35 AM |
|
Philco newbie with P-1891-WA console questions
|
| Hello Jeff ,
Far as the Electrolytic capacitors go here is a list of parts.
that will work . I like using Nichicon and...radiorich — 09:50 PM |
|
Philco newbie with P-1891-WA console questions
|
| Well, I've been stumped at trying to get the first of 11 electrolytic capacitors. I got a schematic and have a list of t...Jeffcon — 07:54 PM |
|
Model 80 Antenna Issue?
|
| Thanks Gary and Rod.
I also found an article in the Philco Repair Bench under Service Hints and Tips, about installi...Hamilton — 12:32 PM |
|
Model 80 Antenna Issue?
|
| Hello Hamilton, here is a little information found in our Philco Radio Library at the bottom of the Home page. Hope it ...GarySP — 11:28 AM |
|
Model 80 Antenna Issue?
|
| I did as you suggested and touching the middle of the volume control did nothing so the coil has to be rewound. Any idea...Hamilton — 10:19 AM |
|
1949 Motorola 5A9M
|
| This would be the second portable in the "other radios" forum where I have a similar one in my collection. I h...Arran — 12:41 AM |
|
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
|
| Hi PittsburgTost.
The record changer looks like a Garrard or BSR (Likely Garrard). The spindles just pull out and pu...MrFixr55 — 11:57 PM |
|
Who's Online
|
| There are currently no members online. |
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
