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

Troubles With FM Alignment On 46-480
#1

AM aligned beautifully. FM has no reception at all to begin with. Steps 1 and 2 of FM alignment go well but in step 3 C32 is very unstable, or maybe eratic is a better word, and just by touching it with my alignment tool increases reception slightly. When I am able to get a somewhat stable reading and proceed to step 4, I'm seeing no changes at all throughout this step of the procedure. I guess pull the trimmer can out and check trimmer C32 to start with? Other ideas would be greatly appreciated.
#2

sometimes, I have found the pushbutton contacts were not making good connections in some cases. Also, sets that use the loctal-type tubes & sockets were notorius for not making good connections unless the pin connections are all cleaned really,really well. I usually scrape the loctal tube pins carefully with a exacto knife to make sure they get good connections all around the tube sockets (bright shiny clean). Just tryin to help with a couple suggestions of sometimes overlooked culprit-probs in sets that use the local-type tubes. Icon_wink
#3

Icon_biggrin Thanks Tex. When I put this thing together I cleaned all the Loctal sockets along with the tube pins themselves. Well today I pulled the tubes and cleaned the sockets again with a small wire brush. Similar to a gun barrel cleaning brush but smaller. I also took a piece of emery cloth to the tube pins. Still didn't work but when I wiggled the tubes it would work again. So I took the tubes and actually bent the pins out just a hair and reinstalled them. Seems to have good FM now. Who ever invented the Loctal and what good is it if they weren't dependable. I've had trouble with them on another radio. Anyway I aligned the radio and it works great now. Thanks!
#4

...glad you bent those tube pins for good connection! I forgot to mention that! The best way to "clean" the tube pins on loctal tubes, is by actually hand-scraping each individual pin with a exacto-knife blade till "shiny".
Most usually, wire brushes, emory cloth, dont have enough cleaning power when dealing with those type tubes! It takes "force" to get those pins clean(scraping) again for proper contact with the loctal-sockets! It is also a good idea to spray WD-40 on both the tube pin tips , and sockets to keep the loctals-connections (all) from corroding again in the near future, or they will in high-humidity type climates! You bet, bad tube design invention from the get-go,period!!
Anytime you have a prob with any radio using loctal-type tubes after full re-cap, most usually, the residual probs of alignment or etc, can be traced back to the loctal tube design!
Ive been told by several WW2 USAF radio-techs, that the loctal-type tubes were originally designed by "JAN" ( IE: joint Army/NAVY) to be used in the WW2 era aircraft Radar systems,etc, and lots of them failed at very in-opportune times of warfare!! Im sure lots of Radio mfgrs of that era snapped the leftover JAN type loctal type tubes up to be used in "receivers" only for a very modest/ quantity price back in those days to be used in home type radio receivers! Zenith also used lots of the loctal type Govt leftovers in their production runs of tube radios also, as well as most other mfgrs! Now, all us vintage radio techs get to deal with them!! Icon_wink




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
New member
Love the pic! I'm southern IL, so wouldn't be much help and Bob Anderson is very good on those, but lives in Chicago are...TV MAN — 05:25 PM
Philco 40-120C Filament Wiring
:thumbup:klondike98 — 04:56 PM
Philco 40-120C Filament Wiring
With these values I think you are OK; the Cmax for this tube is 40uF. Your Vbb could rise a bit, but probably not too mu...morzh — 04:53 PM
Philco 40-120C Filament Wiring
BTW, someone had replaced the original 20uF/20uF filter cap with a 47uF/33uF cap. Do you think these values are safe on ...bluecap — 04:33 PM
Philco 40-120C Filament Wiring
You're correct. I was misinterpreting the key position. I now know where it is, and things are making sense. I appreciat...bluecap — 04:29 PM
Philco 40-120C Filament Wiring
I think Morzh has a good thought. Check the key position. The under chassis diagram in the Philco info shows an “H” for ...klondike98 — 04:25 PM
Philco 630csx power cord
Yes, the third wire goes to the stud on the side and is separate from the other two. I've usually used cloth covered ...Tynwald — 03:09 PM
New member
Have you tried Alabama Historical Radio Society? They possibly could recommend someone. I remember a name of Dee Hanes...morzh — 03:08 PM
Philco 46-480 Electronic Restoration
Nope, he can’t tell me the dimensions. Looks like I won’t be buying it.jrblasde — 02:38 PM
Philco 46-480 Electronic Restoration
Hello Joseph , It sounds like you found a good seller and yes shipping is really expensive ! Sincerely Richardradiorich — 02:16 PM

[-]
Who's Online
There are currently 4023 online users. [Complete List]
» 1 Member(s) | 4022 Guest(s)
Avatar

>