[gary rabbitt]

Hi all,
It's been a while since I've posted here. I need to catch up on all these threads.
I do have a current problem, perhaps it's a simple fix. Working on a Philco 60, run 3. Rebuilt the blocks, and filters.
Replaced a couple out of spec resistors.
Serviced the tuning cap, no shorts. Tubes test fine.
I do notice that someone had possibly rewound the OSC coil. I have not taken it out to inspect yet, nor have I replaced he mica cap inside the coil form.
Here is the issue: Set receives fine from the AM low end , then tuning up the band, will quickly be silent about 1200kc. I have to tune back to about 1000kc, then can tune up to 1200 again- cuts out. It is not shorting at tuner plates. It doesn't abruptly cut off, but drops very fast at a certain point.

Would a poorly wound OSC coil cause reception to drop off? Too many, or too little turns?
I have tweaked the trimmer caps by ear, but have not done a proper alignment yet due to time.
If the IF is off, would that case the issue? It receives very well otherwise.
SW band sounds dead, maybe an alignment issue. (Not worried about SW at the moment). If I get free tonight, I will do a quick check of the IF. Anything thoughts of what might cause this would be appreciated.
Thanks!!! Gary.

[Phlogiston]

You are on the right track. Having to drop down in freq. to get it started again is a symptom of the osc. shutting down.

[morzh]

Also a bad 6A7 tube. Had that on my 38-15 on SW band.

[Radioroslyn]

If you don't have enough turns on the feedback winding you will loose the hi end of the band. I'd say replace the 6A7 and check the coil.
Terry

[Ed Locker]

If the tickler coil was wound backwards, the high end will drop out.
Try reversing that winding.

Ed

[Steve Davis]

+1 to what Terry said. Try another 6A7, if that doesn't help, add a few turns to the feedback coil.

Steve

[gary rabbitt]

Thanks everyone, I'll check everything you mentioned. I did find that the part of the antenna coil was open. The little .7 Ohm section to ground. I tried bypassing that to gnd, with no help, other than a louder signal. Another thing to repair.
As far as the OSC coil I have not removed it yet to inspect. I may go ahead and rewind it properly while it's out.
I did align the set last night as far as I could, and it was tuning across the band. But if I am on a feq of say 1400, turn the bandswitch to SW then back, nothing on AM until I tuned downward and tuned back up.
I see a bad soldering job on the coil lugs, and looks like masking tape where the rewind is. If I get some time this evening, I'll pull the coil and have a look.
Thanks as always for your ideas, and I will report back.
Take care, Gary.

[Ed Locker]

Excerpt from the Master :

The outer winding must be made counterclockwise. The oscillator will not work properly if the outer winding is made clockwise.

I do not remember the correct number of turns at present; that information is downstairs, I am upstairs, it is bedtime and I'm not going to look tonight.

You should use 38 gauge wire on that outer winding.

--------------------------------------------------------------------------------
--
Ron Ramirez
Ferdinand, IN

Ed

[gary rabbitt]

Thanks Ed,
First, I rewound the small antenna coil as it was open. Stronger signals now, but no change in the dropoff symptom.

I have rewound about 5 osc coils already. I just pulled this one out, someone already has attempted a rewind. There's about 14 turns on the outer winding, I believe Ron says 18T of #38 wire.
Going to do the rewind and see what happens. I am deciphering the previous work, and it appears it may have been wound CW instead of CCW.
Would the set still work somewhat (it is sensitive, and sounds ok otherwise, except for the dropoff on the high end) if it was wound backwards?
Looking from the bottom, starting at terminal 3, it is wound CW going to term. 2. So I' am going to make it, right and a much cleaner rewind. I use old strips from photogaphic film as an insulator.
Swapped out the 6A7 tube, no change.

Will check back later this evening. Thanks!

[morzh]

Try first the same direction.

The oscillator would not work AT ALL if it were backwards. If it works in part the direction is likely correct. Unless the oscillator does not oscillate but acts as RF amp and ...but this should not work either as your dial will be totally screwed up.

[Ron Ramirez]

Actually, in my experience, the oscillator in Model 60 sets will sometimes "sort of" work when the outer winding has been rewound in the wrong direction.

Rewinding the outer winding CCW rather than CW cured the problem and restored proper operation.

A note for those who may not have had the pleasure (?) of rewinding a Philco coil - There are guys out there who say you can use any size wire you want. That is pure bravo sierra. The wire gauge ideally should be the same as original; yes, you can use a gauge that is -slightly- off larger or smaller, but not significantly larger or smaller.

A cheap micrometer from Harbor Freight will be an excellent investment for rewinding these coils. Measure the diameter of the original wire with the micrometer and compare the reading to a wire table; then buy a small spool of magnet wire that is as close as possible to your measurement.

And my sincere thanks to Ed Locker for the "blast from the past."

[gary rabbitt]

Hi guys!
Success! The (outer) coil was rewound in the wrong direction. (See photo) Cruddy job they did, put the tape right over the original plastic insulator.
I not only have BC, but the SW band too. The lower part of the ant coil was open, so I did that one also.
What is really odd, some mentioned that the BC band would not receive at all, or the dial would be way off. Well, when it was backwards, the dial was very accurate, and except for the dropoff around 1300kc, seemed fine.

So the chassis is going back into it's home cabinet.
Next set.... another model 60. I did remove the Osc coil on that one, looked pretty good, except for a slight amount of "green" on one of the wires. I am going to rewind it as long as it's out.
Thanks to all again for the help.
Gary.
   

[morzh]

Great.

Do the alignment anyway.

[gary rabbitt]

Yes, I always do the alignment, would never let one go back without it.
My point was, that if the coil was wound so poorly (and backwards), it is strange that it was still receiving, and pretty much accurately.
Now, on to the customer's second model 60, which should be a lot less troublesome.
Thanks to all.

[morzh]

It probably acted as a TRF set. Though I am not 100% sure how.