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

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

39-30 chassis work
#6

Not to hijack your thread.  But I have a 39-30, and I'm just sort of curious if yours has the same factory changes as mine did.

I've seen at least 2 other threads describing this change (picture below).  Basically it seems Philco took AVC off the IF grid.  They disconnected the secondary of the 2nd IF from the AVC line, and instead tied it in to the CT bias voltage resistor via a 490k resistor and they added a .05uF bypass cap.  If you look at the schematic for the 39-36 (which is almost the exact same circuit/chassis, but shoved into a console), the schematic documents this circuit from the factory.

The other 2 changes are in the tone circuit.  I've seen one other post about R25 (hanging off the tone tap).  It's listed as 32k.  But in the radio it was 51k from the factory, as was mine.

And the other change is also in the tone circuit, but I haven't seen anyone mention.  C39 on the tone control is listed as .006 uF, but was .008 uF from the factory.  Although, that is probably such a small difference, it doesn't matter much.   Edit: Actually, I now see this was the cap that someone put a bumble bee in on yours.

As for my 39-30, I'm chasing down a distortion issue.  There is a thread over at ARF that some people have been helping me with, but no luck so far.  I had a thread here too earlier in the year, but never got much traction.  I'd love to compare some notes with you when you finish yours up to see if I can find any discrepancies on mine.


Attached Files Image(s)
   


Messages In This Thread
39-30 chassis work - by klondike98 - 11-13-2015, 03:17 PM
RE: 39-30 chassis work - by klondike98 - 11-15-2015, 09:42 PM
RE: 39-30 chassis work - by Ron Ramirez - 11-16-2015, 08:42 AM
RE: 39-30 chassis work - by sam - 11-16-2015, 12:53 PM
RE: 39-30 chassis work - by klondike98 - 11-16-2015, 01:08 PM
RE: 39-30 chassis work - by Nick3092 - 11-16-2015, 11:37 PM
RE: 39-30 chassis work - by klondike98 - 11-17-2015, 01:39 AM
RE: 39-30 chassis work - by klondike98 - 11-17-2015, 04:50 PM
RE: 39-30 chassis work - by klondike98 - 11-30-2015, 09:46 PM
RE: 39-30 chassis work - by klondike98 - 12-01-2015, 01:26 PM
RE: 39-30 chassis work - by sam - 12-01-2015, 01:37 PM
RE: 39-30 chassis work - by Nathan Slingerland - 12-01-2015, 03:50 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Philco 610B oscillator wiring
Some info from Beitmans says late production. David   David — 06:06 PM
Restoring Philco 96
Oh wow! Just found this thread.  Brings me back to early days on this phorum.  I did a 96 back in 2017.  Thread here: ...rfeenstra — 06:05 PM
Philco 610B oscillator wiring
Thanks for the replies. It's not the really the hum that I am after. Just trying to understand why only the shortwave ba...Tubester — 04:01 PM
Restoring Philco 96
70 and 90 are Superhets, but at least the 2x45 model of 90 uses the Plate detector (and so does 70). Also the Atwaters,...morzh — 03:28 PM
Restoring Philco 96
Morzh, Prayers for your mom. I am sure that there was enough pain living through the Holocaust as a child. I pray dail...MrFixr55 — 02:19 PM
Philco 610B oscillator wiring
Hi Dan, Divide and conquer. First off trry to differentiate between 60Hz and 120 Hz hum. 120 Hz hum has a higher pit...MrFixr55 — 01:49 PM
Restoring Philco 96
Yes, other than takin a toll on your back, they are undeed way more repair friendly than many other Philcos. To me, som...morzh — 01:04 PM
Philco 610B oscillator wiring
If the wires look like they were this way from the factory (very neat and very dull soldering joints), I'd leave them be...morzh — 12:58 PM
My Philco 37-116 Restore
I managed to open up the Expander Unit and replace the grid cap wires. Tested the connections found they looked good and...dconant — 12:19 PM
610B Oscillator Questions
I've included a picture of the 'actual' schematic I created. I double checked several times and it appears to be accur...Tubester — 09:26 AM

[-]
Who's Online
There are currently 2486 online users. [Complete List]
» 2 Member(s) | 2484 Guest(s)
AvatarAvatar

>