I knew not that the speaker was re-coned....you've all given me things to look into and try...
and I certainly want to come to K-town, thanks for the invite! Not sure I can or can't this time. It starts today, and I gotta work!
-Simon
If I am tight and it was re-coned it is a good thing: new cones sound better than the original, especially those from 20 as it used the solid spider instead of the 45RPM flexible one.
Radioroslyn,
I connected to a ground, (a lab cart which is connected to electrical ground), and most noise went away, but still 60 cycle.
Then, I checked resistance between tuning cap stator and ground, and got 4.5 ohms with VOM, and 4.2 ohms with VTVM. That's not "20-50 ohms" so something amish there?
Now for the good stuff. I disconnected the .09 across the filter choke, and NO HUM! hear video:
https://youtu.be/ps6rPDlPOzM
The wire I disconnected went to the Mershon positive terminal.
SO, just one more question (as Columbo would say, but then leads to even more); will this thing run ok on the 120 volts ok without burning up the tubes etc., or what is a good check on that?
Chas,
You were spot on with your "fix the radio first, then clean it up" sage advice for the greenhorn, and I appreciate that.
-Simon
The resistance is right on the money so you're good there.
I would have no problem w/leaving the cap across the choke out.
The simple answer to the line voltage question is to measure the 2.5v heater voltage and use that as a guide the to determine the proper line voltage. If it's say 2.7v then maybe but if it's 3v or higher then use a variac to adjust the line to 2.5v and see what the line voltage is. Then if you like you can use a bucking transformer to drop the line down a bit.
GL
Very good Radioroslyn!
It looks like we are getting lucky here: on 120v line voltage the 80 tube heater measures 5.AC (+ a needle) on the VOM, and the rest, including the 45’s, measure 2.4. I’ve been running it on 110v thru a variac, but won’t need that anymore I reckon.
We did find original knob for the on/off switch (well, Ben did)
So, looks like we are good to go!
OK Ben, time for the cabinet! (No pressure haha!) -This is a Father/Son project, and it’s going to turn out ok, I think.
NEXT UP? We just won a local auction on a 19B, and it’s painted white.....I’m going to go pick it up
Thanks,
Simon
Thanks, morzh! May this thing live for another 88 years! And me too- lets see, that would make me 154 yrs old....
Should you live that long, you will start collecting and restoring iPhones.