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Philco 46-480 Schematics
#46

That advice really helped. I ordered some of that paper. For now, the AM and SW work great. I am now battling one issue and I think it is related to the previous person's mods they made. They had tried to open the secondary of Z301 (from ground) and inject the signal bypassing Z300 and the primary of Z301. I have the FM now working even though it is very low in magnitude and a big loss of signal at the low end. I did find a loose solder connection on L401C, maybe there are more issues in those tuned circuits. The one issue that I face now: I can tune Z301 to peak off line by signal injecting but..... when I apply power the voltage on C314 drives really hard (in the order of -50 vdc). There may be self oscillations happening (?). When I do tune this transformer off-line, then I knock out my AM, so then I adjust Z301 for AM - works great but now it's like a dog chasing his tail. So I basically can't do a full FM Alignment because of this C314 voltage issue - I've convinced myself that these tuned circuits are the reason the FM is not working correctly. Maybe I need to pull out the can again and check for shorts (?). I think this was the problem the last guy faced. Maybe I'll step back and completely go through the FM checks - it seems like on 7F8, from the FM checks, I should read a negative voltage ( I think it was pins 1 to 4). I'm really hoping that is not the problem area because it's pretty tight in that area with the band switch and socket right below it. I ordered a set of fly-legs just so I could reach under the band-switch to take measurements. This unit was going to be a gift to my son so I am not ready to throw in the towel. Any advice or suggestions from the experts would really be appreciated.


Messages In This Thread
Philco 46-480 Schematics - by HarryWeatherford - 08-15-2026, 05:15 PM
RE: Philco 46-480 Schematics - by klondike98 - 08-15-2026, 08:12 PM
RE: Philco 46-480 Schematics - by jrblasde - 08-16-2026, 02:53 PM
RE: Philco 46-480 Schematics - by David - 08-16-2026, 03:13 PM
RE: Philco 46-480 Schematics - by Arran - 08-16-2026, 07:42 PM
RE: Philco 46-480 Schematics - by jrblasde - 08-16-2026, 10:06 PM
RE: Philco 46-480 Schematics - by jrblasde - 08-17-2026, 07:39 AM
RE: Philco 46-480 Schematics - by RodB - 08-17-2026, 10:36 AM
RE: Philco 46-480 Schematics - by Arran - 08-17-2026, 12:57 PM
RE: Philco 46-480 Schematics - by Arran - 08-17-2026, 02:45 PM
RE: Philco 46-480 Schematics - by jrblasde - 08-17-2026, 03:48 PM
RE: Philco 46-480 Schematics - by jrblasde - 08-17-2026, 03:54 PM
RE: Philco 46-480 Schematics - by klondike98 - 08-19-2026, 12:17 AM
RE: Philco 46-480 Schematics - by MrFixr55 - 08-19-2026, 08:45 AM
RE: Philco 46-480 Schematics - by jrblasde - 08-19-2026, 08:46 AM
RE: Philco 46-480 Schematics - by MrFixr55 - 08-19-2026, 09:14 AM
RE: Philco 46-480 Schematics - by RodB - 08-19-2026, 10:32 AM
RE: Philco 46-480 Schematics - by Arran - 09-01-2026, 06:04 PM
RE: Philco 46-480 Schematics - by jrblasde - 09-19-2026, 06:24 PM
RE: Philco 46-480 Schematics - by jrblasde - 09-19-2026, 10:29 PM
RE: Philco 46-480 Schematics - by jrblasde - 09-19-2026, 10:36 PM
RE: Philco 46-480 Schematics - by jrblasde - 09-20-2026, 06:10 PM
RE: Philco 46-480 Schematics - by jrblasde - 09-24-2026, 05:23 PM
RE: Philco 46-480 Schematics - by radiorich - 09-24-2026, 06:45 PM
RE: Philco 46-480 Schematics - by DaleHCook - 09-25-2026, 06:08 AM
RE: Philco 46-480 Schematics - by HarryWeatherford - 09-27-2026, 07:00 AM
RE: Philco 46-480 Schematics - by RodB - 10-01-2026, 03:39 PM



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