Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Output transformer question.
#1

Wondering if anyone can give me some information about an output transformer on an AA5 that uses a 50C5 power output tube. The radio im working on is a Silvertone catalog number 6 radio. I've completed the recap and changed several of the out of tolerance resistors. When I checked the output transformer windings, the primary measures 336 ohms and the secondary measures .6 ohms. According to the schematic,  the primary should be 185 ohms and the secondary .6 ohms. Was wondering,  can output transformers go up in value like resistors do when they get old or could this be a change in the transformer specs when the radio was made. Sometimes manufacturers change specs and they don't make it into an updated schematic; I could be wrong here. Anyway, can I use this transformer or should Iook for a replacement? Don't want to burn up a tube or something. Thanks for any suggestions.
#2

I wouldn't loose any sleep over it.
The dc resistance doesn't mean a whole lot as a number to verify  the the ac impedance of the primary. As for burning up something the worst that could (but unlikely) is  that the primary could open up do to excessive current flow. This would have to do with the rating of the transformer and not the set itself. If there was a mismatch between the tube and transformer you would have low volume and distortion. The ratings for many of the tubes used in ac/dc sets are the same so a transformer that was used with a 50C5 could be used with a 50B5, 50L6, 35L6, 35C5, 35B5, 25B6, and 25L6 there probably a few more. Transformers from an ac set using tubes like 2A5, 47, 42, 41, 6F6, 6V6, and 6F6 aren't a good match as these tube have a higher plate load impedance.
OBTW to answer your question no. Just like wire wound resistors they don't drift like carbon counterparts.

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!

Terry
#3

Wirewound resistors and anything wirewound do not just go up in value.
If your transformer measures twice the value written this possibly could mean two things: 1) error in the sch. 2) the xfmr was replaced at some point.
If it works it is a good transformer. Is it original - can't tell you. Maybe not.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
PT-6 antenna connections
Hi Bridcarl +1 on the others.  Pin 6 of the 7C6 is the AVC Diode so it is appropriate that that pin 4 of the coil con...MrFixr55 — 07:30 AM
462ron
Joseph, this is beyond awesome. A lot of thought and engineering went into this and you hit a home run! Now I must save ...462ron — 07:27 AM
Cannot Adjust an IF Transformer’s cores
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM
Cannot Adjust an IF Transformer’s cores
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM
PT-6 antenna connections
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM
Cannot Adjust an IF Transformer’s cores
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM
PT-6 antenna connections
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4. Yes, pin 6 of the 7C6 is...RodB — 07:34 PM
bridkarl
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM
Cannot Adjust an IF Transformer’s cores
Joseph, now you are an engineer!!RodB — 06:37 PM
PT-6 antenna connections
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM

[-]
Who's Online
There are currently 3632 online users. [Complete List]
» 3 Member(s) | 3629 Guest(s)
AvatarAvatarAvatar

>