08-14-2009, 11:34 PM
Hi Randal, Ron and everyone
Thanks for the tips.
I have been having fits with this set the last few days.
<<EDITED>> I have just read the Philco from He** text about a cantakerous model 89, symptoms sounded like this one.
I had already tried the heating of the coil a few days ago with no luck.
A little history and my current situation.
(Even though this is the AM/SW set which is a code 123, I am using the early diagram for the AM only using the # 36 tube. The bakelite blucks match up with that set, I have recapped according to their original part content.)
OK I was able to receive stations, but only on the high end. Took the grid cap off the 36 tube and it would receive all the way across the band! Ooooo K.
After about 10 minutes it would just stop receiving at all. I have a sig generator and when it was receiging It aligned very well. Tuning cap is very clean. Mica sheets in the trimmers look clean.Receiving lots of stations at night.
Ok, next day, fired it up, received half the band again. (I reconnected the grid cap)After messing with it as far as looking for a loose connection which I didn't find, the thing would oscillate on the high end of the band! Receive well below about 900khz. Tuning higher it would start to squeal. Grounds good, tube shields in place the works.
Today squeal still there, tried to realign, no change.
What could be next? This afternoon for some reason, the set stopped working totally. The stages past the IF was ok, audio had strong buzz when tube cap touched.
Last resort, I pulled the oscillator coil that is widely known to cause issues.
Now I am not positive, but I think that one of the hair wire leads was broken near the terminal. No problem. But when tested for continutiy it showed open.
I connected one lead to one end of the winding (This is the small winding on the outside of the coil) and I probed on the wires that were wound. It had continuity until I got about halfway across, then it was open. (See photos)
So, the break in in the winding itself. Time to do a rewind I guess.
Here are the questions I am dealing with right now.
***Is this the winding that needs to be rewound after the "baking in the oven" procedure? As seen in the photo it's the smallest winding.
***How many turns should it have? I believe I have the same diameter wire on hand.Looks like about 29 to 32 turns.
*** Is the winding just one layer?
I assume there are no taps on this winding. The diagram shows just a small coil on the Cathode of the 36 tube.
NOTE: I had measured this winding when I first started and it measured 150 Ohms. The spec says 5.25 Ohms.
Probably part of my original problem.
Here's the pics.
[Image: http://antiqueradios.com/gallery/d/91130-1/Phil89a.JPG]
[Image: http://antiqueradios.com/gallery/d/91132-1/Phil89b.JPG]
I really hate to give up on any set, but this one is getting the best of me. It's for a customer/friend and I like to get it out of here ASAP.
Thanks for everyone's help.
Gary.
Thanks for the tips.
I have been having fits with this set the last few days.
<<EDITED>> I have just read the Philco from He** text about a cantakerous model 89, symptoms sounded like this one.
I had already tried the heating of the coil a few days ago with no luck.
A little history and my current situation.
(Even though this is the AM/SW set which is a code 123, I am using the early diagram for the AM only using the # 36 tube. The bakelite blucks match up with that set, I have recapped according to their original part content.)
OK I was able to receive stations, but only on the high end. Took the grid cap off the 36 tube and it would receive all the way across the band! Ooooo K.
After about 10 minutes it would just stop receiving at all. I have a sig generator and when it was receiging It aligned very well. Tuning cap is very clean. Mica sheets in the trimmers look clean.Receiving lots of stations at night.
Ok, next day, fired it up, received half the band again. (I reconnected the grid cap)After messing with it as far as looking for a loose connection which I didn't find, the thing would oscillate on the high end of the band! Receive well below about 900khz. Tuning higher it would start to squeal. Grounds good, tube shields in place the works.
Today squeal still there, tried to realign, no change.
What could be next? This afternoon for some reason, the set stopped working totally. The stages past the IF was ok, audio had strong buzz when tube cap touched.
Last resort, I pulled the oscillator coil that is widely known to cause issues.
Now I am not positive, but I think that one of the hair wire leads was broken near the terminal. No problem. But when tested for continutiy it showed open.
I connected one lead to one end of the winding (This is the small winding on the outside of the coil) and I probed on the wires that were wound. It had continuity until I got about halfway across, then it was open. (See photos)
So, the break in in the winding itself. Time to do a rewind I guess.
Here are the questions I am dealing with right now.
***Is this the winding that needs to be rewound after the "baking in the oven" procedure? As seen in the photo it's the smallest winding.
***How many turns should it have? I believe I have the same diameter wire on hand.Looks like about 29 to 32 turns.
*** Is the winding just one layer?
I assume there are no taps on this winding. The diagram shows just a small coil on the Cathode of the 36 tube.
NOTE: I had measured this winding when I first started and it measured 150 Ohms. The spec says 5.25 Ohms.
Probably part of my original problem.
Here's the pics.
[Image: http://antiqueradios.com/gallery/d/91130-1/Phil89a.JPG]
[Image: http://antiqueradios.com/gallery/d/91132-1/Phil89b.JPG]
I really hate to give up on any set, but this one is getting the best of me. It's for a customer/friend and I like to get it out of here ASAP.
Thanks for everyone's help.
Gary.
