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

Thread Closed

Philco 40-165
#16

Once again your expertise is invaluable.
The power transformer secondary resistance reads a little low.  The schematic has half the secondary at 420 ohms and the other half at 400 ohms.  I get about 300 ohms on one side and about 345 ohms on the other.  The primary reads 18 ohms just as the schematic says it should and the filament windings read <.1 ohm.  Should it be replaced or is it within tolerance?

Einstein once said, "I have no special talents, I am only passionately curious."

Jim
#17

Wouldn't lose any sleep over it. Would measure the ac voltage @ the rectifier plates (without the rectifier in place) to see if it's close. Then leave it on for a little while to see if the transformer get hot.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#18

I have searched for a 270 ohm resistor the schematic calls shows, however, no matter how many times I trace the old wiring I come back to a 470 ohm resistor that looks as if it was put in after manufacture.  The soldering on the leads is shiny and sloppy.  The after market notes I have do not indicate a change however my notes are probably incomplete.  Should I replace the 470 with a 470 or replace it with a 270 the schematic indicates?
Thanks...Jim
#19

For now I'd leave it. What it does is set the - bias voltage for the 41 and 7C6. THe important part is when you get it working measure the - voltage on pin 4 of the 41. RCA sez you need about -15vdc there. If you lower the resistance you will low the amount of bias voltage. If you do change it you'll need a 3-5watt job to replace it.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
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
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

[-]
Who's Online
There are currently 1366 online users. [Complete List]
» 1 Member(s) | 1365 Guest(s)
Avatar

>