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

Thread Closed

Philco 46-480 Replacing Field Coil w/ Perm Mag (I know I know)
#9

Hi Retrorev,

Sounds like your wiring is correct. make some voltage readings. All of the Radio's current goes through that resistor. This is a somewhat strange setup in that the field coil was in the B Power Supply return. That wsa done years ago by RCA to keep the field coil voltage above (or below) chassis ground as low as possible. To troubleshoot:
- With all tubes in place, carefully check the voltage between the Audio Output transformer red wire B+ and Chassis Ground. DANGER!!! This is high voltage. Voltage should be around 250V. Check across the 100 0Ohm Resistor and note the voltage. - Check across C59 (Between Rectifier Cathode and center tap of HV Secondary). The sum of the B+ Voltage and the voltage across the resistor should equal the voltage across C59, which will likely be between 300 and 350 Volts DC.

If this is all good, inject an audio signal from a CD, MPE, etc. Headphone jack through a 47K Resistor between the junction of C47, r26, C42 and R20, and chassis ground. Clean audio should be heard from the speaker. If so, the power supply and Audio Section are good. troubleshoot the RF, IF and Detector section.

Hope this helps.

Best Regards,

John, MrFixr55

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
RE: Philco 46-480 Replacing Field Coil w/ Perm Mag (I know I know) - by MrFixr55 - 09-13-2022, 03:09 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
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
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM

[-]
Who's Online
There are currently 1540 online users. [Complete List]
» 1 Member(s) | 1539 Guest(s)
Avatar

>