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

Thread Closed

Philco 42-380X Reception problems
#8

To adjust the IF can compensators you would inject the signal though a cap into terminal 4 of the antenna terminal strip in the back of the radio. Terminal 1 goes to the output xformer, so use that one to connect a high impedance meter (also through a capacitor) to measure signal strength while you move the compensators. (You can also listen to the speaker volume.) Underneath the parts list, the Riders page gives a table and some notes to explain all of this, but I'd still advise reading the chapter on alignment in Elements of Radio Servicing before tackling it.

Edited to add:

I went back and read your original questions about the functions of the compensator adjustments. As near as I can tell, they are as follows:

29A, 29B, 31A, and 34A on the IF cans are to adjust the resonance of the interstage transformers to exactly the intermediate frequency of 455 KHz. If any one of these is off, it will reduce your sensitivity by filtering out the intermediate frequency.

4A, 4B are to tune the antenna for the broadcast band and shortwave band, respectively.

4, 4C, 4D, and 4E are to adjust the tracking of the oscillator for the various bands so that the dial pointer will show the right frequency at every point. If these are out of adjustment, you can adjust the pointer to one station's frequency on the dial, but it will point to the wrong frequencies as you track above and below the one station you set.

Except for the IF cans, these adjustments should be made with the chassis in the cabinet and the loop antenna connected, injecting the signal generator frequency indirectly by making a loop of a few turns of wire and setting it up close to the radio's loop antenna. Then follow the instructions in the Rider's manual in the table and the notes under it. Elements of Radio Servicing Explains this loop antenna connection in Chapter 22, page 415.

Edited to add: Antique Electronic Supply has 41 tubes ST style 50% off until September 30. I'd replace those bad ones you have ASAP.

John Honeycutt


Messages In This Thread
Philco 42-380X Reception problems - by David B - 09-14-2008, 09:51 AM
Re: Philco 42-380X Reception problems - by Raleigh - 09-16-2008, 11:14 AM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
hello david, I have a similar generator in my collection that features a cast iron, single-cylinder Briggs & Stratt...radiorich — 01:00 AM
under chassis parts locator diagram for 1938 Zenith 9s262
Has anyone gone to the trouble of creating an under chassis parts locator image?  Yes, I can identify components by foll...bobloney — 08:57 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Try looking at this site the book mark is for a old generator that I was given. David    https://radionerds.com/index.ph...David — 08:36 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Hello Everyone, I am looking for voltage identification for all the pin positions on the socket of a CRV-20130 power su...Tonym4704 — 08:16 PM
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM

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

>