Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Philco 39-7 not tracking
#2

Jim,

I do not "know" this radio...

The schematic gives me a clue and your description, something is not working correctly in the oscillator circuit .

Check the DC resistance of the oscillator coil, please use a VOM. It should closely agree to the published values. Lift one side of the 110pf mica cap #5 attempt to measure if you can looking for +-5 pf. Or, sub in a new 110pf dipped silver mica. Do not twist the old cap to measure. Cross check your cap measuring device with a new mica cap. Trust the new cap when comparing the old.

Any alignment adjustment that does not have an effect has a problem in its associated resonant circuitry, Bad coil(s) leaking condensers, dramatically changed resistors.

Any corrective work in the oscillator or RF, even pushing a wire out of the way, will affect alignment.

If there is a altered value of resistance in the oscillator coil AND there is a celluloid liner between the primary and the secondary, quite possibly there is corrosion to the coils...
 From A. H. Ghirardis Radio Troubleshooter manual, note, does not address calibration errors...

Sorry, it is a snip of a poor PDF. Download and open in an image processor to enlarge.

   


If the tuning condenser is mounted on grommets, if these sag will that effect calibration?

Chas

Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”


Messages In This Thread
Philco 39-7 not tracking - by Jimradio - 09-25-2023, 03:20 PM
RE: Philco 39-7 not tracking - by Chas - 09-25-2023, 09:46 PM
RE: Philco 39-7 not tracking - by Jimradio - 09-26-2023, 02:23 PM
RE: Philco 39-7 not tracking - by Chas - 09-26-2023, 04:24 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

[-]
Who's Online
There are currently no members online.

>