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

Thread Closed

I Need To Clarify CT Connection
#1

This is on a 40-190.
http://www.nostalgiaair.org/PagesByModel...013339.pdf
I believe someone wired this set wrong and I need to clarify the connection of the CT of the high voltage output from the power transformer. Originally when I got this set the CT was connected to chassis ground. My notes and pictures verify this. I don't know if this is why the rectifier was blown and the power transformer was fried but I don't believe this CT goes to ground in this set. I believe it's B-.

The CT should be isolated from ground and connected to part #60, 150 ohm 1 watt resistor, neg. side of the 12ufd filter cap and on from there. Is this statement correct?

Thanks,
Pepper

"It's Nice To Be Nice To The Nice"
Major Frank Burns Mash 4077th
#2

Yes you are right if this is the correct schematic. Looks like an 'expert' was in there. Hope the power transformer isn't fried. Have a look at all the speaker, field coil, voltage dividers and add a fuse to the set.
#3

Thanks! Someone was in here alright and the power supply that's on it now is not original. This was discussed in another post. It's high voltage output is 250-0-250 and the 84 rectifier was changed to a 5Y3. Even though the 5Y3 has a plate rating of 350-0-350 I'm told the 5Y3 should be fine and same for this transformer. All my filaments add up to 2 amps and this transformers 6.3Vac output is rated at 2.5 amps. Find out when she smokes.

Audio output transformer was fried. Got another on order. Everything else you mentioned looks okay but I'm overhauling the whole set anyway. Except for in a Zenith, I've never seen this much dried and cracked wiring. Maybe the set was dinked with so bad that all the wiring got hot, dried and cracked. Icon_lol

Johnny

"It's Nice To Be Nice To The Nice"
Major Frank Burns Mash 4077th
#4

Nah its a problem with all the rubber coated wiring from the late 30's and 40's. It's funny some color of wiring is fine and other colors are so bad just looking at them seems to make the coating fall off.

-Keith
#5

I need more clarification but this time on the connection of the + side of the 12ufd filter cap #61. The radio was altered and is running a 5Y3 rectifier instead of the 84. The 84 had the indirectly heated cathode but the 5Y3 doesn't have a cathode. I've looked at other radios that are running a 5Y3 and it looks like the + side of my 12ufd will connect to the field coil as shown on the schematic but also connect to one leg of the 5Y3 filament. Is this correct? Here is the NA copy of this 40-190.
http://www.nostalgiaair.org/PagesByModel...013339.pdf

Thanks,
Pepper

"It's Nice To Be Nice To The Nice"
Major Frank Burns Mash 4077th




Users browsing this thread:
[-]
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 no members online.

>