37-690 Alignment - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: 37-690 Alignment (/showthread.php?tid=25386)

---

37-690 Alignment - Radiodial - 11-16-2024

The IF's aligned easily, except for this step where it appears you are expected to get two peaks on either side of the IF freq. That just doesn't  happen, and I'm not sure how it ever would unless I'm misunderstanding the instructions. My interpretation: "adjust signal generator back and forth between 460 and 480, you should get equal 2 signal peaks, one at 465 and one at 475.  If you don't, adjust the primary padder of 94 left and right of peak until you do".  I can wrench on that padder all day long and never get anything other than a single peak at the 470 IF.  Any thoughts as to what I'm doing wrong?
           

---

RE: 37-690 Alignment - radio1 - 11-18-2024

The coils have probably degraded, holding corrosion and moisture and your won't get that double high fidelity peak. Make sure your sig gen and hookups are in good shape and not causing it. Old test leads that have bad connections in the alligator clips can mess it up, leading you down the wrong path. Clean the fidelity contriol also.

---

RE: 37-690 Alignment - Radiodial - 11-18-2024

I got the double peak alignment part to work by:
1- Discovered that "Fidelity control in expanded position" means turn the Selectivity/Treble control Counter-Clockwise.
2- Wearing hearing protection and increasing the volume to full and setting the signal generator output to high.
The other key was all it takes is minuscule adjustments on the 94P coil, and sure enough, you are able to get dual peaks 5khz eeither side of the 470 khz IF.

---