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

Philco 38-3 alignment
#1

Completely following the instructions for aligning the Philco 38-3 on the schematic and completely getting nowhere.  Performing the IF align first, then moving to the RF.  The mag tuning switch is closed.  I have a digital frequency counter in line with my signal generator.  I connect the signal gen lead to the cap of the  6A8G, and have tried it with and without the usual lead also attached. Negative for the sig gen is attached to the chassis.  Once I think I've lined up the IF circuit, I can hear the tone continue as I turn the dial to the first position for starting the RF alignment.
The closest I'm able to get is about 60 KC away from where a station should be.  IE, 1080 is coming in at 1020, 650 is coming in at 590, etc.
When the rotary dial is fully closed, it's in line with the tuning gang, so I know it's not off.

I'm getting plenty of clear stations, they are just not in the right place!!!!! Icon_crazy
#2

So, the oscillator seems to be working OK, just at the wrong frequency. You should be able to adjust trimmer 27 to move the oscillator frequency. Try tuning to a station then tweek the trimmer slightly to see if the station moves up or down the dial. With so many trimmers, you could be on the wrong one.
#3

Thanks Rod, I'll give that a try.  I am watching on a multimeter and also listening as I go through the alignment process to get the highest peaks possible.
I just can't turn the volume all the way up - it kills my ears!!!   (and the cat has put out a contract on my life)
#4

Rod, that closed the gap by half, but I'm out of room to adjust 27 any farther...




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
trying to identify this wire type
Thanks to all for the feedback. As Arran said, it is probably an older replacement and yes it has a grid cap so I will ...georgetownjohn — 09:32 PM
trying to identify this wire type
It's possible that the red wire, actually a grid cap lead, is a very old replacement, I can't remember seeing a pre 1939...Arran — 09:18 PM
Gilfillan Brothers Car Radio?
Hi everyone,  Special thanks to Joe Rossi for tracking down this obscure radio and thanks to others who took up the hun...Antipodal — 08:15 PM
trying to identify this wire type
Here's one source for your wire of many. Take care and BE HEALTHY! Gary P.S. Can't get the right color you need? I ...GarySP — 06:40 PM
trying to identify this wire type
...and modern wire of the appropriate gauges and insulation V-rating (300V minimum, usually shown right on the wire) is ...morzh — 05:47 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
I have a question about this radio, is there anyone that has access to this radio that has an intact unmolested speaker ...captainclock1988 — 04:28 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
Well what makes me confuse all of those companies is that all three of those companies (Setchell-Carlson, Stromberg-Carl...captainclock1988 — 04:21 PM
trying to identify this wire type
The red wire is rubber covered wire. The others are cotton braid over rubber often in colors or a tracer, also strand...Chas — 02:43 PM
trying to identify this wire type
Greetings Phorum members, Hope you can help me identify this type of wire in the photo I have attached.  I am not sure ...georgetownjohn — 01:53 PM
Philco 60 Squealing
All correct shields must be in place, all tubes correct no subs of any kind. Check any soldered, riveted ground conne...Chas — 01:24 PM

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

>