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

48-1270 alignment
#1

I've recently recapped a 48-1270. Its working pretty well but I want to fine tune it to improve reception - I'm a little distant from good stations. The Philco service manual has pretty good instructions for alignment of the 48-1270, but I need a little more elaboration on the first alignment step for AM. The manual instructions for attaching the signal generator for step one reads as follows "Through a .1-mf condenser to aerial section of tuning gang." I am familiar with the stator section of the tuning gang, but I am having difficulty determining which part is the aerial section. I've tried to determine through schematic but can't be sure. So, I've tried this: There are two lugs on top of the condenser - one over each tuning section. When I touch the lug farthest from tuning cord with my finger the signal for a strong AM station gets considerably stronger. When I touch the lug closest to the tuning cord the signal disappears. Does this help discriminate between aerial and oscillator sections. I am guessing the first lug (farthest from tuning cord) is the aerial section. I sure would appreciate some help on this - don't want to mess this up really bad. Thanks.
#2

On the sch there are 3 sections shown. Top to bottom, the middle one (next to R411) I think is the Aerial.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

Thanks morzh for redirecting my attention to the schematic. I was having a little trouble mapping the schematic to the physical tuning condenser. However, I noticed in schematic that WS2(F) pin 7 connects the aerial to the condenser. So, I "followed" that wire with a continuity check to the proper lug. I think I am good to go.
#4

AM alignment went well. Set performs pretty well with built-in loop antenna. Will work on FM alignment later.




Users browsing this thread:
[-]
Recent Posts
Philco Model 38-7: what caps & resistors do fail typically?
Since you stated earlier, you have a console 38-7XX.  They also had a 38-7T (table), and 38-7CS (chairside).  A very nic...GarySP — 01:18 PM
Part numbers to model cross
That I wouldn't know, but sometimes the radio document itself shows one, same as the capacitor cans' etc pinouts.morzh — 12:46 PM
Part numbers to model cross
Thank you morzh, that is exactly what I was looking for. Now , is there some where that shows pinouts for Philco power ...Jim Dutridge — 11:37 AM
Restoration of the Canadian General Electric A-87
Thanks for your help Michael. In fact, this video is only an intermediate result. Later I had to apply another tinting l...RadioSvit — 09:01 AM
Restoration of the Canadian General Electric A-87
Great job on the cabinet. PS. In the US notation, "kenotron" refers to specific type of tubes; we call re...morzh — 08:24 AM
Part numbers to model cross
This document has at least some tables of models and parts used. Example: Choke 32-7572, used in 604 radio. Search f...morzh — 08:19 AM
Restoration of the Canadian General Electric A-87
I also checked all the radio tubes on my Hickok 530 tube tester. The 5Z3 kenotron turned out to be faulty, all the other...RadioSvit — 08:02 AM
Restoration of the Canadian General Electric A-87
Well... While the varnish is drying up, I started repairing the chassis... Of course I started by replacing the pa...RadioSvit — 07:12 AM
Philco Model 38-7: what caps & resistors do fail typically?
Hello Martin, Welcome aboard our little community what great Model 38-7 Sincerely Richardradiorich — 12:30 AM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum Martin. I count about 9 paper caps, the 3 electrolytic caps and 2-Y2 safety caps to replace th...RodB — 09:44 PM

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

>