07-28-2007, 06:14 PM
Well, the audio problem was something incredibly stupid. After all of this time rechecking my recap job, wiring changes, etc. I decided to inject a signal into the grid of the 75 tube, and it worked fine, but not with the external grid wire attached. so, I removed the tube shield for the 10th time and examined the grid wire, and someone had passed it through the tube socket eyelet and it finally shorted out when I had put in the new 75 tube and slid the shield down for the 10th time!
Now, back to my squealing or heterodyning problem on the AM band. I checked again and I must have the newer IF can types as well as the proper compensating trimmers too, so I can now say that all of the newest mods are in place for this model. It is more sensitive for sure, but now I really do need help with finding the cause of my squealing only on certain stations, all of which are below 1000 KHZ on the AM band. Changing the length of the antenna affects this issue some, but does not correct it. I can adjust the antenna trimmer and it has a similar effect, of course. Any suggestions would be appreciated as now I can focus on this one remaining problem. I'm wondering if not using the wavetrap that Philco calls for is causing this issue? This is where I need someone with experience with this chassis to advise. Maybe someone can actually respond this time, I feel dumb talking to myself here!
Now, back to my squealing or heterodyning problem on the AM band. I checked again and I must have the newer IF can types as well as the proper compensating trimmers too, so I can now say that all of the newest mods are in place for this model. It is more sensitive for sure, but now I really do need help with finding the cause of my squealing only on certain stations, all of which are below 1000 KHZ on the AM band. Changing the length of the antenna affects this issue some, but does not correct it. I can adjust the antenna trimmer and it has a similar effect, of course. Any suggestions would be appreciated as now I can focus on this one remaining problem. I'm wondering if not using the wavetrap that Philco calls for is causing this issue? This is where I need someone with experience with this chassis to advise. Maybe someone can actually respond this time, I feel dumb talking to myself here!
