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: 1 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
Sorry. The test points are as follows: 1 - 0v 2 - 0v 3 - 0v 4 - 12v 5 - 0v 6 - 11.9v 7 - 12v 8 - 12v 9 - 12v...R3Sons — 02:09 PM
6TPZ and 5TPO Radio Help
OK, so 18 and 19 as they should be. What is "everything else?" Try to be more specific in your descriptions:...morzh — 12:44 PM
6TPZ and 5TPO Radio Help
Yeah, I'm still on 5TPO. Sorry, my bad, points 1 and 2 should be points 18 and 19 (easy mistake  :think: )  X7 is shown ...R3Sons — 11:42 AM
Philco 40-120C Filament Wiring
Hi folks, I'm in the process of restoring a Philco 40-120C and I'm finding the wiring to be a bit puzzling. According to...bluecap — 11:28 AM
462ron
Hi Levi, here’s just a thought. Most radios run the oscillator higher than the dial setting. Say you set your radio to 1...462ron — 10:10 AM
1930s Stewart-Warner Tombstone Radio need help identifying model number
Another Update: I found a couple of damaged coils inside this radio that might have something to do with why this radio ...captainclock1988 — 10:51 PM
6TPZ and 5TPO Radio Help
If you are still on 5TPO, you lost me there. What X7? What Points 1 and 2?morzh — 08:37 PM
6TPZ and 5TPO Radio Help
Quick progress report: X7 is broken. Only one leg soldered, the other missing and the diode is cracked. I've replaced...R3Sons — 05:05 PM
6TPZ and 5TPO Radio Help
Oh...and you have electrolytic caps there. All need to go and be replaced.morzh — 04:36 PM
6TPZ and 5TPO Radio Help
Thanks, will do.R3Sons — 01:25 PM

[-]
Who's Online
There are currently 5273 online users. [Complete List]
» 1 Member(s) | 5272 Guest(s)
Avatar

>