41-608 with BOL changer - 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: 41-608 with BOL changer (/showthread.php?tid=22286)

---

RE: 41-608 with BOL changer - RodB - 06-26-2021

Gary, good find on the BOL light. All the times I took a computer service call to find a light source askew from the sensor. You might try rectifying the 6.3 v into a 27 ohm resistor then 4 1N4002 diodes in series. Each diode has about .7 volts drop, should give you 2.8 - 3 volts constant. Oh, you'll probably need an electrolytic before the resistor, maybe 100 mfd 16 volts.

---

RE: 41-608 with BOL changer - GHMueller - 06-26-2021

Hi Rod, Thanks for the advice.

I've done some further testing and found out that I can get the exciter light to illuminate. I had to turn the compensator (part 11B on the schematic) all the way up as far as I can get it without forcing it. It still isn't quite as loud as using 2 @1.5 vdc batteries = 3v. Close however. Maybe the compensator is going bad. When I am adjusting it without the lamp connected, but connected to a volt-ohm meter, I seem to be able to adjust the ac voltage well past 3 vac, but it seems a bit inconsistent. But under load conditions with the meter I get about, maybe 2 volts.

It looks like a tuning capacitor on the schematic. Unfortunately I do not have and specs on this component.

---