06-17-2015, 05:17 PM
Thanks for the advice on the cabinet earlier. I'm pretty sure how I want to go there, now. I've done my cleaning, desoldering, and measuring on the set itself. The rheostats check out good, and the RF coils as well. The three tuning condensers turn great and I show no shorts on the plates. I replaced the grid leak resistor, grid resistors, and the .3 mfd capacitor. Oddly, the primaries on both interstage transformers were bad, so I ordered the p-t156 transformers from AES and they came in today. I put the transformer cases in the freezer overnight and the old transformers popped right out with no problem and no damage to the cases. So far all is well. I'm a bit terrified of putting the transformers in wrong since this is my first time to attempt it. My issue is I'm puzzling over the right way to hook up the transformers. The transformers each have a red and a blue wire on one side, and on the other side is a black wire, and two green wires. AES sent the transformers without a schematic drawing.
I'm sure I can disregard the black wire as a center tap, but what are the correct primary and secondary coil wires? I looked up color coding and found this:
From the ARRL Radio Amateur's Handbook:
Plate finish lead (pri.) ------- blue
B+ (power supply) lead --------- red (whether center tap or not)
Plate start lead (pri.) -------- brown
Grid finish (sec.) ------------- green
speaker return (sec.) ---------- black (whether center tap or not)
Grid start (sec.) -------------- yellow
http://www.atwaterkent.info/TechData/Dra...640sch.pdf
Am I correct in thinking on the first transformer the blue goes to the plate of the detector, the red goes to the power switch, green should go to the grid of the 1st audio tube but there are two green wires?
The connection points for that transformer should be the power switch and the grid of the 1st audio tube across the primary winding, and the 22v post and the plate of the detector tube across the secondary winding.
The connection points on the second transformer should be the 90v post and the plate of the 1st audio tube across the primary winding, and the power switch and the grid of the 2nd audio tube across the 2ndary winding.
So if I figure out which wire pairs constitute which windings, and how to keep them in phase (probably not the right term), I should be good?
I'm sure several of you guys have done this many times and could just tell me which colors go where, but I'd like to learn from it. Perhaps someone knows where I can find a color code guide for the wires, although from the code above it looks like blue is plate, red is B+, and green is grid...or do I ignore one of the green wires and use the black? As you can see, I'm a little lost in this.
I'm sure I can disregard the black wire as a center tap, but what are the correct primary and secondary coil wires? I looked up color coding and found this:
From the ARRL Radio Amateur's Handbook:
Plate finish lead (pri.) ------- blue
B+ (power supply) lead --------- red (whether center tap or not)
Plate start lead (pri.) -------- brown
Grid finish (sec.) ------------- green
speaker return (sec.) ---------- black (whether center tap or not)
Grid start (sec.) -------------- yellow
http://www.atwaterkent.info/TechData/Dra...640sch.pdf
Am I correct in thinking on the first transformer the blue goes to the plate of the detector, the red goes to the power switch, green should go to the grid of the 1st audio tube but there are two green wires?
The connection points for that transformer should be the power switch and the grid of the 1st audio tube across the primary winding, and the 22v post and the plate of the detector tube across the secondary winding.
The connection points on the second transformer should be the 90v post and the plate of the 1st audio tube across the primary winding, and the power switch and the grid of the 2nd audio tube across the 2ndary winding.
So if I figure out which wire pairs constitute which windings, and how to keep them in phase (probably not the right term), I should be good?
I'm sure several of you guys have done this many times and could just tell me which colors go where, but I'd like to learn from it. Perhaps someone knows where I can find a color code guide for the wires, although from the code above it looks like blue is plate, red is B+, and green is grid...or do I ignore one of the green wires and use the black? As you can see, I'm a little lost in this.
Charlie in San Antonio
